Electrician installed a whole installation RCD

[Toby]

Hi,

In a small commercial office that was covered by a 12 way Wylex fuse
consumer unit (that had been "upgraded" with MCB's), an electrician
installed a whole installation 30mA RCD recently.

This installation covers about 10 rooms, which includes a total of 8
PC's and associated IT kit.

We are getting this RCD tripping randomly, he came out today, and I
asked if he could firt an 100mA RCD for now, but as he didn't have one
with him, and we need people to be able to work, he is going to replace
the RCD with an isolator "At our request"

My question is, is it against the regs to install this whole
installation RCD in this situation in the first place?

He said it was done because he fond one of the lighting circuits
upstairs didn't have any earth, and this was the easiest way to protect
this.

I basically want to know if we should use him to replace the CU with a
new 17th edition one, probably with RCBO's, or we need to find another
electrician.

Thanks!

--
Toby...
Remove your pants to reply

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[John Rumm]

On 09/11/2015 10:57, Toby wrote:
> Hi,
>
> In a small commercial office that was covered by a 12 way Wylex fuse
> consumer unit (that had been "upgraded" with MCB's), an electrician
> installed a whole installation 30mA RCD recently.
>
> This installation covers about 10 rooms, which includes a total of 8
> PC's and associated IT kit.
>
> We are getting this RCD tripping randomly, he came out today, and I
> asked if he could firt an 100mA RCD for now, but as he didn't have one
> with him, and we need people to be able to work, he is going to replace
> the RCD with an isolator "At our request"
>
> My question is, is it against the regs to install this whole
> installation RCD in this situation in the first place?

Its certainly a deprecated way of designing things, and probably not
really meeting the requirement to maintain discrimination (i.e. limiting
the effects of a fault in one part of an installation on other unrelated
circuits)

> He said it was done because he fond one of the lighting circuits
> upstairs didn't have any earth, and this was the easiest way to protect
> this.

Easiest for him perhaps...

> I basically want to know if we should use him to replace the CU with a
> new 17th edition one, probably with RCBO's, or we need to find another
> electrician.

Assuming his quality of workmanship is ok, then he ought to be able to
do an all RCBO install since there is not much in the way of decision
making ;-)


--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

[Dave Plowman (News)]

In article <n1ptuk$6iu$1...@dont-email.me>,

Toby <ne...@altyourpantsphuk.co.uk> wrote:
> In a small commercial office that was covered by a 12 way Wylex fuse
> consumer unit (that had been "upgraded" with MCB's), an electrician
> installed a whole installation 30mA RCD recently.

> This installation covers about 10 rooms, which includes a total of 8
> PC's and associated IT kit.

> We are getting this RCD tripping randomly, he came out today, and I
> asked if he could firt an 100mA RCD for now, but as he didn't have one
> with him, and we need people to be able to work, he is going to replace
> the RCD with an isolator "At our request"

Just how much office equipment is there in this small office? Things like
computers and peripherals?

But the most likely things to trip an RCD are water heaters or anything
with a 'solid' heating element. These can leak to ground.

> My question is, is it against the regs to install this whole
> installation RCD in this situation in the first place?

> He said it was done because he fond one of the lighting circuits
> upstairs didn't have any earth, and this was the easiest way to protect
> this.

> I basically want to know if we should use him to replace the CU with a
> new 17th edition one, probably with RCBO's, or we need to find another
> electrician.

I'd certainly not fancy having the one RCD protecting everything. Whether
you'd need to go to the expense of RCBOs, I dunno. Being commercial
premises the regs may be different.

--
*A clear conscience is the sign of a fuzzy memory.

Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.

[Tim Watts]

On 09/11/15 13:52, Chris Hogg wrote:

> On Mon, 9 Nov 2015 10:57:44 +0000, Toby <ne...@altyourpantsphuk.co.uk>
> wrote:
>
>> Hi,
>>
>> In a small commercial office that was covered by a 12 way Wylex fuse
>> consumer unit (that had been "upgraded" with MCB's), an electrician
>> installed a whole installation 30mA RCD recently.
>>
>> This installation covers about 10 rooms, which includes a total of 8
>> PC's and associated IT kit.
>>
>> We are getting this RCD tripping randomly, he came out today, and I
>> asked if he could firt an 100mA RCD for now, but as he didn't have one
>> with him, and we need people to be able to work, he is going to replace
>> the RCD with an isolator "At our request"
>>
>> My question is, is it against the regs to install this whole
>> installation RCD in this situation in the first place?
>>
>> He said it was done because he fond one of the lighting circuits
>> upstairs didn't have any earth, and this was the easiest way to protect
>> this.
>>
>> I basically want to know if we should use him to replace the CU with a
>> new 17th edition one, probably with RCBO's, or we need to find another
>> electrician.
>>
>> Thanks!
>

> IANA electrician, but following advice from various better-qualified
> contributors to this NG, when I had my CU upgraded from wire fuses to
> a split way unit with MCP's, I also had a 100A, 100mA time-delayed
> whole-house RCD fitted at the front end, i.e. whole house. This was
> because we have a TT supply, i.e. overhead cables, and apparently with
> a TT supply this level of protection is implied by the regs, if not
> actually spelled out in as many words.
>
> Having a 100mA time-delayed unit does two things: it doesn't trip when
> experiencing small current imbalances, where a 30mA trip would trip,
> and being time-delayed, it allows the 30mA RCD in the CU to trip
> first, isolating the ring mains, which is where the current-imbalance
> fault is most likely to occur, but leaving the light circuit still
> live, so you can still see where you're going at night. Cooker,
> immersion, lights etc. are not on the 30mA RCD, but do have MCB's (as
> do the ring mains on the 30mA RCD).
>

But it will not actually qualify as a device offering protection against
accidental contact on the non 30mA RCD circuits, so you still need
either a split way board with twin RCDs or RCBOs if you wish all the
circuits to be protected.

In either case the delayed RCD has no value outside of TT systems.

[Toby]

On 09/11/2015 13:38, Dave Plowman (News) wrote:
> In article <n1ptuk$6iu$1...@dont-email.me>,
> Toby <ne...@altyourpantsphuk.co.uk> wrote:
>> In a small commercial office that was covered by a 12 way Wylex fuse
>> consumer unit (that had been "upgraded" with MCB's), an electrician
>> installed a whole installation 30mA RCD recently.
>
>> This installation covers about 10 rooms, which includes a total of 8
>> PC's and associated IT kit.
>
>> We are getting this RCD tripping randomly, he came out today, and I
>> asked if he could firt an 100mA RCD for now, but as he didn't have one
>> with him, and we need people to be able to work, he is going to replace
>> the RCD with an isolator "At our request"
>
> Just how much office equipment is there in this small office? Things like
> computers and peripherals?

9 x PC's (I forgot one)
2 servers (via a UPS)
13 monitors (1 is an old CRT)
1 x MFD (Copier)
2 x Printers
1 x Fax
1 x PoE Network switch
2 x desktop Ethernet switches
2 x Routers
1 x Firewall
1 x Wireless Access point
1 x Time attendance RFID reader
1 x Phone System
1 x Shredder
1 x Franking machine
1 x Intruder alarm
1 x Fire alarm
1 x Boiler with an external pump and a wireless thermostat receiver
2 x Small over-sink hot water boilers (Stored water, 13A connections)
1 x Dishwasher

>
> But the most likely things to trip an RCD are water heaters or anything
> with a 'solid' heating element. These can leak to ground.

I will get the hot water boilers checked, I think only one is on anyway.

>> My question is, is it against the regs to install this whole
>> installation RCD in this situation in the first place?
>
>> He said it was done because he fond one of the lighting circuits
>> upstairs didn't have any earth, and this was the easiest way to protect
>> this.
>
>> I basically want to know if we should use him to replace the CU with a
>> new 17th edition one, probably with RCBO's, or we need to find another
>> electrician.
>
> I'd certainly not fancy having the one RCD protecting everything. Whether
> you'd need to go to the expense of RCBOs, I dunno. Being commercial
> premises the regs may be different.
>

Ta.

[Fredxxx]

On 09/11/2015 10:57, Toby wrote:

> Hi,
>
> In a small commercial office that was covered by a 12 way Wylex fuse
> consumer unit (that had been "upgraded" with MCB's), an electrician
> installed a whole installation 30mA RCD recently.
>
> This installation covers about 10 rooms, which includes a total of 8
> PC's and associated IT kit.
>
> We are getting this RCD tripping randomly, he came out today, and I
> asked if he could firt an 100mA RCD for now, but as he didn't have one
> with him, and we need people to be able to work, he is going to replace
> the RCD with an isolator "At our request"
>
> My question is, is it against the regs to install this whole
> installation RCD in this situation in the first place?
>
> He said it was done because he fond one of the lighting circuits
> upstairs didn't have any earth, and this was the easiest way to protect
> this.
>
> I basically want to know if we should use him to replace the CU with a
> new 17th edition one, probably with RCBO's, or we need to find another
> electrician.
>
> Thanks!

I think a single RCD protection is ok as long as you have emergency
lighting.

Given your setup and the potential loss of data etc when a trip occurs,
I wouldn't have any hesitation to have a full RCBO setup.

In theory he should be able to test insulation of your boiler, and a PAT
check on your other items if need be.

I have known PC PSUs to cause nuisance trips. In reality after
investigating and ruling out the obvious boiler, it could be anything!

[dennis@home]

On 09/11/2015 14:43, Toby wrote:

>> But the most likely things to trip an RCD are water heaters or anything
>> with a 'solid' heating element. These can leak to ground.
>
> I will get the hot water boilers checked, I think only one is on anyway.

Unless its a double pole isolator a leak from the neutral can trip a
RCD. Most fused spurs are only single pole.

[spuorg...@gowanhill.com]

On Monday, 9 November 2015 10:55:27 UTC, Toby wrote:
> He said it was done because he fond one of the lighting circuits
> upstairs didn't have any earth, and this was the easiest way to protect
> this.

He could have put a RCD FCU on the supply to the lighting circuit if that was all he was worried about.

And I think the fire alarm panel (if it's a commercial panel system) MUST NOT be on an RCD circuit but should be on a protected cable like MICC or Fireproof which does not need RCD protection, connected as close as possible to the origin of the installation.

If he's taken your fire alarm installation out of its BS compliance then there may be costs to correct this at the next annual inspection, and insurance implications meantime.

Anyone putting a single RCD on an installation with 12 circuits these days needs their understanding of the Regs questioned.

Owain

[Peter Parry]

On Mon, 9 Nov 2015 14:43:01 +0000, Toby <ne...@altyourpantsphuk.co.uk>
wrote:

>On 09/11/2015 13:38, Dave Plowman (News) wrote:
>> In article <n1ptuk$6iu$1...@dont-email.me>,
>> Toby <ne...@altyourpantsphuk.co.uk> wrote:

>> Just how much office equipment is there in this small office? Things like
>> computers and peripherals?

>9 x PC's (I forgot one)
>2 servers (via a UPS)
>13 monitors (1 is an old CRT)
>1 x MFD (Copier)
>2 x Printers
>1 x Fax
>1 x PoE Network switch
>2 x desktop Ethernet switches
>2 x Routers
>1 x Firewall
>1 x Wireless Access point
>1 x Time attendance RFID reader
>1 x Phone System
>1 x Shredder
>1 x Franking machine

That should be more than enough noise filters to make an RCD wobbly.

[harry]

On Monday, 9 November 2015 10:55:27 UTC, Toby wrote:

You can determine the cause by leaving items turned off one by one until the problem stops.
Start with stuff that only runs intermittently.

All your portable equipment should be PAT tested anyway.

[charles]

In article <eec32be8-2b49-4308...@googlegroups.com>,

However, a PAT test won't necesarily show up a fault which is either
intermittent or takes time to develop.

--
Please note new email address:
cha...@CandEhope.me.uk

[The Natural Philosopher]

On 09/11/15 13:52, Chris Hogg wrote:
> On Mon, 9 Nov 2015 10:57:44 +0000, Toby <ne...@altyourpantsphuk.co.uk>
> wrote:
>

>> Hi,
>>
>> In a small commercial office that was covered by a 12 way Wylex fuse
>> consumer unit (that had been "upgraded" with MCB's), an electrician
>> installed a whole installation 30mA RCD recently.
>>
>> This installation covers about 10 rooms, which includes a total of 8
>> PC's and associated IT kit.
>>
>> We are getting this RCD tripping randomly, he came out today, and I
>> asked if he could firt an 100mA RCD for now, but as he didn't have one
>> with him, and we need people to be able to work, he is going to replace
>> the RCD with an isolator "At our request"
>>
>> My question is, is it against the regs to install this whole
>> installation RCD in this situation in the first place?
>>
>> He said it was done because he fond one of the lighting circuits
>> upstairs didn't have any earth, and this was the easiest way to protect
>> this.
>>
>> I basically want to know if we should use him to replace the CU with a
>> new 17th edition one, probably with RCBO's, or we need to find another
>> electrician.
>>
>> Thanks!
>

> IANA electrician, but following advice from various better-qualified
> contributors to this NG, when I had my CU upgraded from wire fuses to
> a split way unit with MCP's, I also had a 100A, 100mA time-delayed
> whole-house RCD fitted at the front end, i.e. whole house. This was
> because we have a TT supply, i.e. overhead cables, and apparently with
> a TT supply this level of protection is implied by the regs, if not
> actually spelled out in as many words.
>
> Having a 100mA time-delayed unit does two things: it doesn't trip when
> experiencing small current imbalances, where a 30mA trip would trip,
> and being time-delayed, it allows the 30mA RCD in the CU to trip
> first, isolating the ring mains, which is where the current-imbalance
> fault is most likely to occur, but leaving the light circuit still
> live, so you can still see where you're going at night. Cooker,
> immersion, lights etc. are not on the 30mA RCD, but do have MCB's (as
> do the ring mains on the 30mA RCD).
>

I think this is in many ways the best solution, A 100mA slo blo is good
for the hole house as some gross issues will cause it to trip, but RCBOs
on specialised mains - stuff that goes outside, or maybe kicthen and
workshop - is well worth it


--
the biggest threat to humanity comes from socialism, which has utterly
diverted our attention away from what really matters to our existential
survival, to indulging in navel gazing and faux moral investigations
into what the world ought to be, whilst we fail utterly to deal with
what it actually is.

[Tim Watts]

On 09/11/15 16:59, Chris Hogg wrote:

> When you say it won't qualify as a device offering protection against
> accidental contact on the non 30mA RCD circuits, do you man according
> to the regs?

Yes - 30mA, 40mS trip time or lower/faster. I can't quote the reg number
off the top of my head.

Try electrical.theiet.org/wiring-matters/15/insp-test-rcd.cfm?type=pdf

which has a list of regs against RCD types.

> As it offers whole-house protection, it must offer some
> protection to the non 30mA RCD circuits, although it will obviously be
> a bit less sensitive.

It offers ADS (automatic disconnection of supply) fault protection
(which is why you have it with a TT installation as your Live-Earth loop
impedance is not low enough to trip a breaker or the main fuse in the
required times because it cannot generate a high enough fault current.

>
> As the items connected to the non 30mA RCD circuits are permanently
> wired in, they're less likely to be a hazard than items plugged into
> ring-main sockets, that are frequently plugged/unplugged and moved
> around. At least, that was the thinking (not mine) for having the
> set-up as I have. Probably not appropriate for the OP though, given
> his particular situation.
>

Please note that I am NOT saying a 30mA RCD is required on all circuits
in a commercial installation. What I am saying is: please don't confuse
a 100mA RCD as offering " slightly less" protection than a 30mA/40mS RCD
as regards protection against accidental (human) contact. It provides no
recognised protection. So it is effectively pointless (unless you have a
TT earth).

Cheers,

Tim

[Dave Plowman (News)]

In article <5640bed5$0$37718$b1db1813$abf...@news.astraweb.com>,

dennis@home <den...@nowhere.invalid> wrote:
> Unless its a double pole isolator a leak from the neutral can trip a
> RCD.

> Most fused spurs are only single pole.

Really? How far back are you going?

--
*I didn't like my beard at first. Then it grew on me.*

[ARW]

"dennis@home" <den...@nowhere.invalid> wrote in message
news:5640bed5$0$37718$b1db1813$abf...@news.astraweb.com...

Are you making this up?



--
Adam

[ARW]

"Toby" <ne...@altyourpantsphuk.co.uk> wrote in message
news:n1ptuk$6iu$1...@dont-email.me...

> Hi,
>
> In a small commercial office that was covered by a 12 way Wylex fuse
> consumer unit (that had been "upgraded" with MCB's), an electrician
> installed a whole installation 30mA RCD recently.

Then he is either a prick, a cowboy or just following instructions from the
client for the cheapest possible job (lets assume the later is not true).

An all RCBO or High integrity CU is the the way forward.

http://wiki.diyfaq.org.uk/index.php/17th_Edition_Consumer_Units

may help - you will have to juggle the circuits from the domestic approach
given to those setups to suit your needs (eg the computers need to be on
their own RCBO).

--
Adam

[Tim Watts]

I'll just add that all the refurbs in universities seem to regard RCD
protected power circuits as "undesirable". The trend there seems to be
no RCD protection at circuit level and sockets with inbuilt RCDs in
certain vulnerable places - eg seminar rooms were students are likely to
jack in.

[dennis@home]

On 09/11/2015 17:56, Dave Plowman (News) wrote:
> In article <5640bed5$0$37718$b1db1813$abf...@news.astraweb.com>,
> dennis@home <den...@nowhere.invalid> wrote:
>> Unless its a double pole isolator a leak from the neutral can trip a
>> RCD.
>
>> Most fused spurs are only single pole.
>
> Really? How far back are you going?
>

Well most of the trade packs on screwfix don't say they are DP.
Only the crabtree and MK do.
Which ones do you think the electrician is going to buy if the customer
doesn't specify?

[ARW]

"dennis@home" <den...@nowhere.invalid> wrote in message

news:5640f9d9$0$27908$b1db1813$5240...@news.astraweb.com...

Give a link to one that you think is single pole.

--
Adam

[ARW]

"harry" <harry...@btinternet.com> wrote in message
news:eec32be8-2b49-4308...@googlegroups.com...

That's what all the PAT testers tell you.

PAT testing is a con.


--
Adam

[charles]

In article <n1r0dv$ikh$1...@dont-email.me>, ARW

PAT testing - because one year is up since the last test IS a con. PAT
testing on a proper risk assessed basis can show up faults - but most are
seen on the visual bit for which you don't need a meter. I have some RED
stickers and I have used them. Once on a piece of brand new kit.

[John Rumm]

We are probably talking about a pre 17th edition install, where no
direct contact protection on lighting circuits etc would have been the
norm.

> In either case the delayed RCD has no value outside of TT systems.

There are times where you want fire and installation protection and
cascaded RCDs - so they still have their uses.

[John Rumm]

With that much IT kit, you probably ought to consider high integrity
earthing as well on the computer circuits, since all those mains input
filters will likely contribute to a high non fault leakage current.

[Dave Plowman (News)]

In article <1a67hc-...@squidward.sv.dionic.net>,

Tim Watts <tw_u...@dionic.net> wrote:
> I'll just add that all the refurbs in universities seem to regard RCD
> protected power circuits as "undesirable". The trend there seems to be
> no RCD protection at circuit level and sockets with inbuilt RCDs in
> certain vulnerable places - eg seminar rooms were students are likely to
> jack in.

Fine if you have an unlimited budget, as so many of these places seem to.
IMHO, totally unnecessary for a small office.

--
*"I am " is reportedly the shortest sentence in the English language. *

[spuorg...@gowanhill.com]

On Monday, 9 November 2015 18:47:05 UTC, Tim Watts wrote:
> I'll just add that all the refurbs in universities seem to regard RCD
> protected power circuits as "undesirable". The trend there seems to be
> no RCD protection at circuit level and sockets with inbuilt RCDs in
> certain vulnerable places - eg seminar rooms were students are likely to
> jack in.

Perhaps partly because they have older distribution boards for which RCBOs aren't available and changing the boards would be A Big Job involving lots of disruption to other users (and a cost to the estates budget rather than the seminar room budget).

Depending on the age of the building universities are more likely to have been properly wired in the first place in steel conduit or in dado trunking systems, ie no buried unprotected cables.

Owain

[Tim Watts]

On 10/11/15 11:13, Dave Plowman (News) wrote:
> In article <1a67hc-...@squidward.sv.dionic.net>,
> Tim Watts <tw_u...@dionic.net> wrote:
>> I'll just add that all the refurbs in universities seem to regard RCD
>> protected power circuits as "undesirable". The trend there seems to be
>> no RCD protection at circuit level and sockets with inbuilt RCDs in
>> certain vulnerable places - eg seminar rooms were students are likely to
>> jack in.
>
> Fine if you have an unlimited budget, as so many of these places seem to.
> IMHO, totally unnecessary for a small office.
>

What on earth are you on about?

The sum total of RCD sockets in my place is a few % at most of all sockets.

I did say: certain common/accessible areas. I did not say every office,
lecture room, corridor.

It's certainly cheaper to do what they did than upgrade the circuit
(bearing in mind then they'd have to test the circuit possibly with
dozens of sockets, and these are commercial breaker panels so I expect
RCBOs will cost a little more than domestic ones).

[Tim Watts]

That too...

[Dave Plowman (News)]

In article <70c9hc-...@squidward.sv.dionic.net>,

Tim Watts <tw_u...@dionic.net> wrote:
> On 10/11/15 11:13, Dave Plowman (News) wrote:
> > In article <1a67hc-...@squidward.sv.dionic.net>,
> > Tim Watts <tw_u...@dionic.net> wrote:
> >> I'll just add that all the refurbs in universities seem to regard RCD
> >> protected power circuits as "undesirable". The trend there seems to be
> >> no RCD protection at circuit level and sockets with inbuilt RCDs in
> >> certain vulnerable places - eg seminar rooms were students are likely to
> >> jack in.
> >
> > Fine if you have an unlimited budget, as so many of these places seem
> > to. IMHO, totally unnecessary for a small office.
> >

> What on earth are you on about?

> The sum total of RCD sockets in my place is a few % at most of all
> sockets.

Then you must have many with no RCD protection. To give the same degree of
protection, they'd all have to be RCD outlets. And have you looked at the
cost of them? At least four times that of a non RCD outlet.

> I did say: certain common/accessible areas. I did not say every office,
> lecture room, corridor.

It would be a very brave person who would guarantee there was never a need
for RCD protection on some sockets, while accepting it was needed on
others. In any form of public building.

--
*I am a nobody, and nobody is perfect; therefore I am perfect*

[Tim Watts]

On 10/11/15 15:14, Dave Plowman (News) wrote:

> Then you must have many with no RCD protection. To give the same degree of
> protection, they'd all have to be RCD outlets. And have you looked at the
> cost of them? At least four times that of a non RCD outlet.

If you read back, my point was that universities DON'T tend to have RCD
protection on all sockets - very few IME out of a small sample set.

>> I did say: certain common/accessible areas. I did not say every office,
>> lecture room, corridor.
>
> It would be a very brave person who would guarantee there was never a need
> for RCD protection on some sockets, while accepting it was needed on
> others. In any form of public building.

There'd seem to be a lot of brave people then... Remember, it's not a
domestic environment, nor one deemed to have vulnerable people.

[charles]

In article <5520654...@davenoise.co.uk>,

Dave Plowman (News) <da...@davenoise.co.uk> wrote:
> In article <70c9hc-...@squidward.sv.dionic.net>,
> Tim Watts <tw_u...@dionic.net> wrote:
> > On 10/11/15 11:13, Dave Plowman (News) wrote:
> > > In article <1a67hc-...@squidward.sv.dionic.net>,
> > > Tim Watts <tw_u...@dionic.net> wrote:
> > >> I'll just add that all the refurbs in universities seem to regard RCD
> > >> protected power circuits as "undesirable". The trend there seems to be
> > >> no RCD protection at circuit level and sockets with inbuilt RCDs in
> > >> certain vulnerable places - eg seminar rooms were students are likely to
> > >> jack in.
> > >
> > > Fine if you have an unlimited budget, as so many of these places seem
> > > to. IMHO, totally unnecessary for a small office.
> > >

> > What on earth are you on about?

> > The sum total of RCD sockets in my place is a few % at most of all
> > sockets.

> Then you must have many with no RCD protection. To give the same degree of
> protection, they'd all have to be RCD outlets. And have you looked at the
> cost of them? At least four times that of a non RCD outlet.

> > I did say: certain common/accessible areas. I did not say every office,
> > lecture room, corridor.

> It would be a very brave person who would guarantee there was never a need
> for RCD protection on some sockets, while accepting it was needed on
> others. In any form of public building.

Our local authority, in the case of village halls says "sockets on stage"
must be RCD protected.

[westom]

replying to charles , westom wrote:

> charles wrote:
> Our local authority, in the case of village halls says
> "sockets on stage" must be RCD protected.
> --

Nothing should fault at even 2 milliamps. If something is tripping a 100
ma RCD, then an appliance or some household wiring has a major defect.
Find and fix that serious human safety issue. Never cure symptoms - ie
blame an RCD. Find and fix a human safety defect.


--

[ARW]

"charles" <cha...@candehope.me.uk> wrote in message
news:55206b8b...@candehope.me.uk...

What do you mean by local authority?


--
Adam

[The Natural Philosopher]

work out what the leakage current of 30 PC RFI units with 15nF caps from
live and neutral to earth is.

Well over 30 mA IIRC

[westom]

replying to The Natural Philosopher , westom wrote:

> tnp wrote:
> work out what the leakage current of 30 PC RFI units with 15nF caps from
> live and neutral to earth is.

Maximum that any should leak is 100 microamps. PCs typically leak 60
microamps or less. That is 1.8 milliamps maximum. In other venues, an
RCDs trips on 5 ma - because no appliances all grouped together should
never leak even 5 milliamps.

That 100 milliamp RCD has detected a potentially serious human safety
problem.



--

[charles]

In article <n1toie$ap8$1...@dont-email.me>, ARW

Borough Council who are responsible for issuing licences to such premises.

[Dave Plowman (News)]

In article <n1trkk$3bj$1...@news.albasani.net>,

The Natural Philosopher <t...@invalid.invalid> wrote:
> On 10/11/15 21:44, westom wrote:
> > replying to charles , westom wrote:
> >> charles wrote:
> >> Our local authority, in the case of village halls says
> >> "sockets on stage" must be RCD protected. --
> >
> > Nothing should fault at even 2 milliamps. If something is tripping a 100
> > ma RCD, then an appliance or some household wiring has a major defect.
> > Find and fix that serious human safety issue. Never cure symptoms - ie
> > blame an RCD. Find and fix a human safety defect.
> >
> work out what the leakage current of 30 PC RFI units with 15nF caps from
> live and neutral to earth is.

> Well over 30 mA IIRC

But surely in good nick those present a balanced load to both line and
neutral?

--
*If you can't see my mirrors, I'm doing my hair*

[Dave Plowman (News)]

In article <33fd1$56426522$cf3aab60$29...@news.flashnewsgroups.com>,

Willing to bet in the OP's case it is one of his water heaters.

--
*Some days you're the dog, some days the hydrant.

[Peter Parry]

On Tue, 10 Nov 2015 23:44:01 +0000, westom
<caedfaa9ed1216d60e...@example.com> wrote:

>replying to The Natural Philosopher , westom wrote:
>> tnp wrote:
>> work out what the leakage current of 30 PC RFI units with 15nF caps from
>> live and neutral to earth is.
>
>Maximum that any should leak is 100 microamps. PCs typically leak 60
>microamps or less. That is 1.8 milliamps maximum. In other venues, an
>RCDs trips on 5 ma - because no appliances all grouped together should
>never leak even 5 milliamps.

Where do you get 100uA from? A class1 piece of equipment to IEC 950
(Information Technology Equipment), a PC for example, can have up to
3.5mA of earth leakage current. Moreover an RCD will eventually trip
if continuously subjected to a current imbalance of half its rated
value, so 15mA will eventually trip an RCD. Given a worse case but
compliant leakage it would require only 5 pieces of Class 1 (earthed)
IT equipment to eventually trip a 30mA RCD.

[westom]

replying to Peter Parry , westom wrote:

> peter wrote:
> On Tue, 10 Nov 2015 23:44:01 +0000, westom

> Where do you get 100uA from? A class1 piece of equipment to IEC 950
> (Information Technology Equipment), a PC for example, can have up to
> 3.5mA of earth leakage current.

We design this stuff. Maybe 1 milliamp is acceptable in some undeveloped
nations. But other standards demand well under 100 microamps.
Furthermore, leakage that low is easy. Some venues must have numerous
equipment on the same circuit that would trip at 5 milliamps. 3.5 mA
leakage from any appliance is a serious design or manufacturing flaw.
Especially when microamps are so easily achieved.

I have never seen a standard that permits a leakage that large. A PC
leaking 3.5 ma would cause circuit tripouts in many nations - completely
unacceptable when a computer must be designed for all world power systems.
Those milliamps approach currents that can kill. In many venues, a 5
milliamp leakage would trip RCDs.

If a 100 milliamp RCD is tripping, then the building contains a serious
human safety defect. Fix the defect. Many, instead, want to blame the
RCD.


--

[ARW]

"charles" <cha...@candehope.me.uk> wrote in message

news:5520ca1b...@candehope.me.uk...

Just wondered as I this year I have electrically tested a few village halls
for insurance purposes. The LA had no specific requirements other than a
NICIEC EICR saying the electrics were safe. BTW I would put a lack of RCD on
stage sockets as a code 1.

I failed all of them for various reasons - the main failure at two of them
was an incredibly high Ze to the properties. As they were both tested within
two days of each other I questioned the calibration of test case I was
using. Both were, when double checked, DNO faults.

--
Adam

[charles]

In article <n200t7$rjb$1...@dont-email.me>, ARW

In the case of Guildford, the requirement was a consequence of a
musician/singer peforming at th University being electrocuted when he took
hold of a microphone stand.

[John Rumm]

3.5mA was (is?) the EU legal limit for fixed IT equipment... About the
only thing that came close in the past were large CRT monitors (which
could do up to 2mA by themselves - possibly more on inrush when switched
on from cold).

These days modern kit should not come anywhere near that limit. If you
work on a budget of say 1mA per desk that might not be too unreasonable
given PC, screen and a few other IT gadgets powered.

[John Rumm]

I don't think anyone was suggesting otherwise. We were however
attempting to guide the OP to finding what was causing the problem
rather than just telling him to get it fixed!

[Fredxxx]

On 11/11/2015 16:44, westom wrote:
> replying to Peter Parry , westom wrote:
>> peter wrote:
>> On Tue, 10 Nov 2015 23:44:01 +0000, westom Where do you get 100uA
>> from? A class1 piece of equipment to IEC 950 (Information Technology
>> Equipment), a PC for example, can have up to 3.5mA of earth leakage
>> current.
>
> We design this stuff. Maybe 1 milliamp is acceptable in some undeveloped
> nations. But other standards demand well under 100 microamps.
> Furthermore, leakage that low is easy. Some venues must have numerous
> equipment on the same circuit that would trip at 5 milliamps. 3.5 mA
> leakage from any appliance is a serious design or manufacturing flaw.
> Especially when microamps are so easily achieved.
>
> I have never seen a standard that permits a leakage that large.

That is the most worrying statement someone who claims to be versed in
this subject can ever make.

If you would kind enough to state who you design for, so I can make a
special case of avoiding their equipment?

[Fredxxx]

I presume that means requiring immediate action, why not Code 2 for
requiring improvement?

> I failed all of them for various reasons - the main failure at two of
> them was an incredibly high Ze to the properties. As they were both
> tested within two days of each other I questioned the calibration of
> test case I was using. Both were, when double checked, DNO faults.

Was the Ze issue a supply issue or an earth spike issue?

[Peter Parry]

On Wed, 11 Nov 2015 16:44:02 +0000, westom
<caedfaa9ed1216d60e...@example.com> wrote:

>replying to Peter Parry , westom wrote:
>> peter wrote:
>> On Tue, 10 Nov 2015 23:44:01 +0000, westom
>> Where do you get 100uA from? A class1 piece of equipment to IEC 950
>> (Information Technology Equipment), a PC for example, can have up to
>> 3.5mA of earth leakage current.
>
>We design this stuff.

Oh dear.

> Maybe 1 milliamp is acceptable in some undeveloped
>nations.

You mean like the EU, the USA, Switzerland, Singapore etc?

>But other standards demand well under 100 microamps.

Which ones?

> 3.5 mA leakage from any appliance is a serious design or manufacturing flaw.
>Especially when microamps are so easily achieved.

Nope.

>I have never seen a standard that permits a leakage that large.

Try the one quoted - IEC 60950-1 (Information Technology Equipment)
(IEC 60950-1, 2nd Ed, 2005-12 to give the current version its full
title).

[Peter Parry]

On Wed, 11 Nov 2015 18:43:40 +0000, John Rumm
<see.my.s...@nowhere.null> wrote:

>
>These days modern kit should not come anywhere near that limit. If you
>work on a budget of say 1mA per desk that might not be too unreasonable
>given PC, screen and a few other IT gadgets powered.

I agree a milliamp is probably closer to reality - the one modern
exception seems to be these common plug in "Surge suppression"
plugs/sockets which seem to manage quite high leakage.

[Fredxxx]

On 11/11/2015 15:10, Peter Parry wrote:

A quick look at
http://uk.farnell.com

and
Home > Passive Components > EMC / RFI Suppression > Suppression
Filters - Power Line IEC

Suggests that leakage on an IEC filtered chassis mounted plug/socket is
a few 100uA, typically 300uA plus. That's without any additional "real"
filtering you might have in a piece of equipment.

[Peter Parry]

On Wed, 11 Nov 2015 21:33:26 +0000, Fredxxx <fre...@nospam.com> wrote:

>Suggests that leakage on an IEC filtered chassis mounted plug/socket is
>a few 100uA, typically 300uA plus. That's without any additional "real"
>filtering you might have in a piece of equipment.

And that is for some of the better quality items on the market, not
the average PC PSU.

[Johnny B Good]

On Wed, 11 Nov 2015 18:53:46 +0000, Fredxxx wrote:

> On 11/11/2015 16:44, westom wrote:
>> replying to Peter Parry , westom wrote:
>>> peter wrote:
>>> On Tue, 10 Nov 2015 23:44:01 +0000, westom Where do you get 100uA
>>> from? A class1 piece of equipment to IEC 950 (Information Technology
>>> Equipment), a PC for example, can have up to 3.5mA of earth leakage
>>> current.
>>
>> We design this stuff. Maybe 1 milliamp is acceptable in some
>> undeveloped nations. But other standards demand well under 100
>> microamps. Furthermore, leakage that low is easy. Some venues must
>> have numerous equipment on the same circuit that would trip at 5
>> milliamps. 3.5 mA leakage from any appliance is a serious design or
>> manufacturing flaw. Especially when microamps are so easily achieved.
>>
>> I have never seen a standard that permits a leakage that large.
>
> That is the most worrying statement someone who claims to be versed in
> this subject can ever make.

+1

>
> If you would kind enough to state who you design for, so I can make a
> special case of avoiding their equipment?

I doubt you'll get an answer to that question any time soon.

I suspect westom doesn't know the difference between insulation
breakdown leakage and the reactive leakage you see from the 47nF caps
typically used in the EMI filtering circuit of ATX PSUs.

If the leakage is due to failing insulation, that *is* a serious issue
which does need to be investigated and put right. Reactive leakage due to
EMI filtering otoh, is an altogether different kettle of fish
notwithstanding that enough PCs hooked up to a circuit where the CPC wire
has gone open circuit can present a human safety hazard (but one would
hope that someone would start to question the tingling sensation they get
every time they make contact with the case of the PC(s) in question).

One thing to consider with a single *un-earthed* PC is that the leakage
source is effectively a 120v supply with a leading reactive impedance of
33.863K ohms (voltage divider effect of a pair of 47nF caps in series
across a 240v supply with, effectively, a parallel connection to a very
low impedance 240v 50Hz ac supply).

Even the combined effect of ten such unearthed PCs is unlikely to pose
an electrocution hazard. It's the peripheral connections that are likely
to draw attention to a missing CPC on a UK ring main and a call to an
electrician to solve the mystery of why so many devices are getting fried
whenever they're plugged in or disconnected from the PC (both the
peripherals and the interfaces concerned).

Westom may well specialise in the design of equipment that calls for
such low leakage requirements (medical or specialist research equipment
springs to mind) but if this is the case, then he's specialised his
knowledge to just this subset, an extremely narrow field indeed.
Consequently, he's no longer qualified to comment on the wider field of
leakage currents from general every day kit without the benefit of a
refresher course in "Leakage 101".

Such specialisation to that extreme is very worrying. One such example
that comes to my mind is the case of all those early PCI based sound
cards (and the PCI based on-board sound chips) that started to appear
around the turn of the century which all, to a chip, clipped the line
(and CD analogue audio) inputs at -2dB FSD due to the sound card and MoBo
manufacturers blindly following the reference design offered by the sound
chips makers where the -6dB sensitivity option had been hardwired to
reduce the noise floor.

Basically, this was achieved by doubling the reference voltage for the
ADC but forgetting the need to double the line input buffer amp supply
rail voltage to raise the already marginal clipping level that was
otherwise sufficient when the more sensitive setting had been chosen.

I think it took a good (well, bad really) 5 or more years before the
penny finally dropped and the problem was properly addressed. You had to
be overly focussed (specialised) in the digital aspect and totally
ignorant of the fundamentals of audio circuitry design to miss that
particular "Schoolboy Howler" of design incompetence to make that mistake
(and worse still, perpetrate it for so damned long!).

--
Johnny B Good

[westom]

replying to Peter Parry , westom wrote:

For protection of human life, an RCD must trip at 5 milliamps. Higher
currents (ie 20 milliamps) are permitted if human protection only requires
'let-go' or ventricular fibrillation protection. One standard (that now
applies to North America and will eventually appear in the UK) is UL943.

More facts from design standards. Currents less than 0.5 milliamps are
considered safe. Current between 0.5 and 10 milliamps cause involuntary
muscle contraction resulting in injuries. Currents between 10 milliamps
and 100 milliamps can cause breathing difficulties or even fibrillation.
A 100 milliamp RCD is an inferior safety device. Any fault that trips a
100 milliamp RCD is well above human safety requirements.

How does one design equipment to operate without tripping RCDs that do
human safety (ie 5 milliamps)? That equipment leaks less than 100
microamps. One ANSI standard permits leakages up to 500 microamps. BS
standards will eventually adapt what has long been standard by UL, CSA,
IEEE, and others. Many BS upgrades eventually use phrases directly taken
from those other, older, and safer standards. Apparently you need not
meet international standard.

Properly designed equipment need not leak more than 100 microamps. Designs
typically target 60 microamps. JCAHO and NFPA 99 defines less than 50 and
10 microamps. Another standard permits up to 300 microamps from an
asssembly of many electronic devices. Another standard for small electric
motors with only one layer of insulation permits up to 100 microamp
leakage. All well below an obsolete 3.5 milliamp number that would cause
problems with current technology 5 milliamp RCDs. Even in the days of
vacuum valves (tubes) did not leak that much.

Now back to the OP's problem. If a 100 milliamp RCD trips, then a serious
and troubling human safety issue exists. Above numbers say why that is
dangerous. Fault can be in appliances or in household wiring. Or even a
combination of both.

An informed engineer would not hype on the irrelevant - badly designed
hardware that leaks 3.5 milliamps. As if obsolete standard are good
enough. Microamp leakages numbers were standard and routinely achieved
even 40 years ago. If a fault does not exist, then even 5 milliamps
combined from many appliances would not exist.

A design engineer would target the topic rather than promote obsolete
safety standards. The OP's tripping RCD indicates a serious human safety
issue.

In one case, that fault (that was in building wiring) did not exist until
an appliance was powered by that circuit. It was a more interesting
problem.



--

[Tim Watts]

On 12/11/15 05:44, westom wrote:

> A design engineer would target the topic rather than promote obsolete
> safety standards. The OP's tripping RCD indicates a serious human safety
> issue.

Or just a leaky heating element in a cooker.

[Dave Plowman (News)]

In article <9prdhc-...@squidward.sv.dionic.net>,

Or one of the water heaters he has.

--
*I brake for no apparent reason.

[John Rumm]

On 12/11/2015 05:44, westom wrote:
> replying to Peter Parry , westom wrote:

> For protection of human life, an RCD must trip at 5 milliamps. Higher

Nonsense.

Firstly you need to understand that shock hazards are related not just
to current flow, but also duration.

The shock hazard curves are shown here:

http://wiki.diyfaq.org.uk/index.php/File:RCDShockHazardCurve.png

Secondly keep in mind that RCDs to not limit the current flow in a shock
situation anyway.

> currents (ie 20 milliamps) are permitted if human protection only requires
> 'let-go' or ventricular fibrillation protection. One standard (that now
> applies to North America and will eventually appear in the UK) is UL943.

The UK requirement for direct contact shock protection specifies 30mA
devices for general use. 10mA threshold devices are available for
specialist applications, but are not in general use.

Generally they will operate within two mains cycles (40ms). Its this
quick operating time that is the actual protection mechanism, not the
trip current.

> A 100 milliamp RCD is an inferior safety device. Any fault that trips a
> 100 milliamp RCD is well above human safety requirements.

No one was suggesting otherwise, so you can stop repeating yourself.

[John Rumm]

I suspect that Johnny B may have hit the nail on the head, that
westom[1] is talking about actual insulation leakage from a product and
not reactive coupling from the RFI filter.

[1[ any relation to w_tom one wonders?

[Peter Parry]

On Thu, 12 Nov 2015 05:44:01 +0000, westom
<caedfaa9ed1216d60e...@example.com> wrote:

>replying to Peter Parry , westom wrote:
>For protection of human life, an RCD must trip at 5 milliamps.

Pity that all domestic ones trip at 30mA then.

>Higher
>currents (ie 20 milliamps) are permitted if human protection only requires
>'let-go' or ventricular fibrillation protection. One standard (that now
>applies to North America and will eventually appear in the UK) is UL943.

BS 7671:2008+A3:2015 IET Wiring Regulations Seventeenth Edition came
into effect in July 2015. Residual Current Devices must meet the
standards in BS EN 61008-1:2012.

You are suggesting that these will in some way be replaced by UL943
(Class A, single- and three-phase, ground-fault circuit-interrupters
intended for protection of personnel, for use only in grounded neutral
systems in accordance with the National Electrical Code (NEC)), dated
2006?

You do realise a GFCI and an RCD are functionally identical?. However
a GFCI incorporates an over current trip so is closer to a Residual
Current Breaker with Overload (RCBO) than a RCD. There will normally
be 1 GFCI per socket outlet (Often incorporated into the socket
itself) or small group of radial wired sockets rather than the RCD
covering a ring main which will have many sockets.

Under present UK rules all sockets must have residual current
protection, under the somewhat more lax American NEC rules only those
for use in wet areas need residual current detection.

What on earth makes you think the older UL943 will replace more modern
standards?

>More facts from design standards.

Which design standards?

> Currents less than 0.5 milliamps are
>considered safe. Current between 0.5 and 10 milliamps cause involuntary
>muscle contraction resulting in injuries. Currents between 10 milliamps
>and 100 milliamps can cause breathing difficulties or even fibrillation.
>A 100 milliamp RCD is an inferior safety device.

No it isn't, it has a perfectly valid role to play in TT earthed
circuits.

>Any fault that trips a
>100 milliamp RCD is well above human safety requirements.

That's probably why those installed for protection of the users are
rated at 30mA.

>How does one design equipment to operate without tripping RCDs that do
>human safety (ie 5 milliamps)?

If you are referring to the US wiring system of having one GFCI per
socket - this will allow for the maximum 3.5mA leakage current from
your computer.

>That equipment leaks less than 100
>microamps. One ANSI standard permits leakages up to 500 microamps. BS
>standards will eventually adapt what has long been standard by UL, CSA,
>IEEE, and others. Many BS upgrades eventually use phrases directly taken
>from those other, older, and safer standards. Apparently you need not
>meet international standard.

Do you actually understand the standard naming conventions and the
hierarchy of standards? National standards specify the requirements
for application in the particular country. British Standard – BS
denotes Britain's National Standards which are controlled by the
British Standards Institute (BSI). EN denotes a Standard which is
adopted by the European community and is controlled by the European
Committee for Standardisation (CEN). European standards are aimed at
facilitating commerce between the countries of the European community.
Once a European Standard has been agreed it supersedes any existing
national standard and becomes the new national standard. In Britain
these Standards are then prefixed with BS EN. ISO denotes a worldwide
standard issued by the International Organisation for Standardisation.
Once an International Standard has been adopted as a European Standard
it supersedes the existing European standard. In Britain these
Standards are then prefixed with BS EN ISO.

>Properly designed equipment need not leak more than 100 microamps. Designs
>typically target 60 microamps. JCAHO and NFPA 99 defines less than 50 and
>10 microamps.

Why on earth would you make all domestic equipment conform to medical
equipment standards when there is no advantage in doing so and a
considerable cost increase?

> Another standard permits up to 300 microamps from an
>asssembly of many electronic devices. Another standard for small electric
>motors with only one layer of insulation permits up to 100 microamp
>leakage. All well below an obsolete 3.5 milliamp number that would cause
>problems with current technology 5 milliamp RCDs. Even in the days of
>vacuum valves (tubes) did not leak that much.

You have obviously never worked on an old USA design TV.

However, here is a clue. Old valve equipment didn't use switched mode
power supplies and didn't have to meet any RF emission standards.
Indeed many TV['s were quite effective jammers of short wave radio
bands).

>Now back to the OP's problem. If a 100 milliamp RCD trips,

It is a 30mA RCD which is tripping.

>An informed engineer would not hype on the irrelevant - badly designed
>hardware that leaks 3.5 milliamps. As if obsolete standard are good
>enough.

The "obsolete" standard is several years younger than the American one
you quote.

>Microamp leakages numbers were standard and routinely achieved
>even 40 years ago.

40 years ago switched mode power supplies (SMPSU) were uncommon and
radio frequency interference wasn't an issue. With SMPSU you need
noise filtering to meet the EMC requirements and that introduces
leakage paths.

>A design engineer would target the topic rather than promote obsolete
>safety standards.

.
The standard you are referring to was only published 3 years ago.

I am rather concerned that someone claiming to be involved in the
design of electronic devices seems to never have heard of the
appropriate International standards.

Next thing you will be telling us to switch to 110V because it is
"safer".

[westom]

replying to Peter Parry , westom wrote:

> peter wrote:
> On Thu, 12 Nov 2015 05:44:01 +0000, westom

> You do realise a GFCI and an RCD are functionally identical?. However
> a GFCI incorporates an over current trip so is closer to a Residual
> Current Breaker with Overload (RCBO) than a RCD. There will normally
> be 1 GFCI per socket outlet (Often incorporated into the socket
> itself) or small group of radial wired sockets rather than the RCD
> covering a ring main which will have many sockets.

Again ignorance of what must be done all over the world so that equipment
will work in regions with better safety standards. For example,
everything on a circuit (ie some 20 devices operate on one 5 milliamps
RCD) without tripping it. Because that is found in North American venues
and therefore in major facilities throughout the world. No problem since
electrical equipment must leak typically less than 100 microamps. Even
construction sites must have many equipment on one 5 milliamp GFCI without
tripping. Any equipment that leaks 3.5 ma would cause consternation on
job sites. Same 'less than 5 millampss' applies to secure facilities all
over the world because that equipment is also used in and must also
operate on North American's much safer GFCI standards.

Return to the point; to what is relevant. A tripping 100 mA RCD means a
serious human safety issue. Move on to what the OP must do to have human
safety.

You are arguing nonsense using standards that are considered insufficient
in many venues and for human safety. Relevant numbers for human safety
were for faults of less than one second. 30 milliamp protection is too
high for what are normally one circuit powering 20 appliances. Everything
you have posted demonstrates only local knowledge; insufficient for
international design requirements. And is irrelevant to the OP's problem.

Apparently you want to argue safety standards that are inferior to what
is found elsewhere; rather than address the purpose of this thread. A
useful engineer would address reasons for RCD tripping either due to
appliance failure, interior wiring faults, or a combination of both. And
yes, we have seen where an RCD would only trip due to a combination of
both - which can make solutions challenging. Nuisance tripping happens in
venues with safe wiring when appliances leak an excessive 3.5 mA. But
that is not the OP's problem. OP has a much worse fault that exceeds what
is required for human safety. Move on to what is relevant here.


--

[Peter Parry]

On Thu, 12 Nov 2015 14:44:01 +0000, westom
<caedfaa9ed1216d60e...@example.com> wrote:

>replying to Peter Parry , westom wrote:
>> peter wrote:
>> On Thu, 12 Nov 2015 05:44:01 +0000, westom
>> You do realise a GFCI and an RCD are functionally identical?. However
>> a GFCI incorporates an over current trip so is closer to a Residual
>> Current Breaker with Overload (RCBO) than a RCD. There will normally
>> be 1 GFCI per socket outlet (Often incorporated into the socket
>> itself) or small group of radial wired sockets rather than the RCD
>> covering a ring main which will have many sockets.

>Again ignorance of what must be done all over the world so that equipment
>will work in regions with better safety standards. For example,
>everything on a circuit (ie some 20 devices operate on one 5 milliamps
>RCD) without tripping it.

You have extension leads with 20 things plugged in to them from one
socket!

>Because that is found in North American venues
>and therefore in major facilities throughout the world.

One thing most of the world didn't follow the USA on was, very wisely,
their dire and rather primitive electricity installations.

>No problem since
>electrical equipment must leak typically less than 100 microamps.

Which standard mandates that for IT equipment?

>Even
>construction sites must have many equipment on one 5 milliamp GFCI without
>tripping.

That might explain why electrocution is the second leading cause of
death on American construction sites. 15% of traumatic deaths in the
US construction industry are due to electrocution compared with 1.5%
in the UK.

>Any equipment that leaks 3.5 ma would cause consternation on
>job sites. Same 'less than 5 millampss' applies to secure facilities all
>over the world because that equipment is also used in and must also
>operate on North American's much safer GFCI standards.

The population of the USA is about 6 times that of the UK. In the
year 2009 about 100 Americans died due to electrocution in the home
from consumer products alone.

In the UK in the same year the number of people who died from
electrocution in the home from all causes was 5.

I hope you don't feel offended if we stay with our "inferior" system.

>Return to the point; to what is relevant. A tripping 100 mA RCD means a
>serious human safety issue.

We all agree that a 100mA RCD does not provide adequate personal
protection but we are not talking about that but a 30mA one.

>Apparently you want to argue safety standards that are inferior to what
>is found elsewhere;

You mean the USA having an electrocution death rate at least 3 times
higher than the UK is because of their "superior standards"?

[ARW]

"Fredxxx" <fre...@nospam.com> wrote in message
news:n2031u$4vm$1...@dont-email.me...

That was NICIEC advice.

>> I failed all of them for various reasons - the main failure at two of
>> them was an incredibly high Ze to the properties. As they were both
>> tested within two days of each other I questioned the calibration of
>> test case I was using. Both were, when double checked, DNO faults.
>
> Was the Ze issue a supply issue or an earth spike issue?

Supply issue - both were PME.

--
Adam

[Chris French]

In message <ecf69$5644a5b1$cf3aab60$32...@news.flashnewsgroups.com>,
westom <caedfaa9ed1216d60e...@example.com> writes

>replying to Peter Parry , westom wrote:
>> peter wrote:
>> On Thu, 12 Nov 2015 05:44:01 +0000, westom You do realise a GFCI and
>>an RCD are functionally identical?. However a GFCI incorporates an
>>over current trip so is closer to a Residual Current Breaker with
>>Overload (RCBO) than a RCD. There will normally be 1 GFCI per socket
>>outlet (Often incorporated into the socket itself) or small group of
>>radial wired sockets rather than the RCD covering a ring main which
>>will have many sockets.
>

<snip>

>Return to the point; to what is relevant. A tripping 100 mA RCD means a
>serious human safety issue. Move on to what the OP must do to have human
>safety.

How about reading what the OP wrote.

He doesn't have a tripping 100mA RCD, he has 30 mA RCD that is tripping
>
>You are arguing nonsense

Ahem......

>OP has a much worse fault that exceeds what
>is required for human safety. Move on to what is relevant here.

Really, how do you know that?
--
Chris French

[Adam Funk]

On 2015-11-12, Peter Parry wrote:

> On Thu, 12 Nov 2015 14:44:01 +0000, westom
><caedfaa9ed1216d60e...@example.com> wrote:

>>Again ignorance of what must be done all over the world so that equipment
>>will work in regions with better safety standards. For example,
>>everything on a circuit (ie some 20 devices operate on one 5 milliamps
>>RCD) without tripping it.
>
> You have extension leads with 20 things plugged in to them from one
> socket!

Not directly, of course: you daisy-chain the extension leads. Have
you never seen a meeting where 20+ people have laptops plugged in at
the same time.

[westom]

replying to Peter Parry , westom wrote:
> peter wrote:
> You have extension leads with 20 things plugged in to them from one socket!

Again, your knowledge is only of local wiring standards using inferior
protection.

20 appliances on many receptacles can and must be powered by one RCD that
will trip on 5 milliamps. You should have known that long before denying
and posting. Many appliances on one 5 milliamp RCD is routine in venues
where human safety is better.

Informed engineers routinely design equipment to leak less than 100
microamps. A 3.5 milliamp leakage is unacceptable in venues where better
safety exists. Properly designed equipment must work without tripping any
RCD anywhere in the world - even on construction sites. 20 items, each
leaking 3.5 milliamps, is unsafe, unacceptable, and routinely avoided by
simple and proven designs.

You again subvert this thread with what is totally irrelevant. OP has a
fault so serious as to even trip a 100 milliamp RCD. Can you concentrate
on the topic rather than posting feeling and myths generated by ignorance?
Why do you routinely and repeatedly ignore the OP's problem? Why do you
subvert this thread by promoting unacceptable designs and obsolete
standards? Can you assist the OP?


--

[Fredxxx]

Fair do's. Is that published advice because you said "you would put a
lack of RCD on stage sockets as a code 1" rather than saying that you had?

>>> I failed all of them for various reasons - the main failure at two of
>>> them was an incredibly high Ze to the properties. As they were both
>>> tested within two days of each other I questioned the calibration of
>>> test case I was using. Both were, when double checked, DNO faults.
>>
>> Was the Ze issue a supply issue or an earth spike issue?
>
> Supply issue - both were PME.

I was intrigued - thanks. What was the result, a rapid change to TT?

[Fredxxx]

On 12/11/2015 19:44, westom wrote:
> replying to Peter Parry , westom wrote:
>> peter wrote:
>> You have extension leads with 20 things plugged in to them from one
>> socket!
>
> Again, your knowledge is only of local wiring standards using inferior
> protection.

You sound unemployable.

> 20 appliances on many receptacles can and must be powered by one RCD that
> will trip on 5 milliamps. You should have known that long before denying
> and posting. Many appliances on one 5 milliamp RCD is routine in venues
> where human safety is better.

Nonsense. No "must" about it.

> Informed engineers routinely design equipment to leak less than 100
> microamps. A 3.5 milliamp leakage is unacceptable in venues where better
> safety exists. Properly designed equipment must work without tripping any
> RCD anywhere in the world - even on construction sites. 20 items, each
> leaking 3.5 milliamps, is unsafe, unacceptable, and routinely avoided by
> simple and proven designs.
>
> You again subvert this thread with what is totally irrelevant. OP has a
> fault so serious as to even trip a 100 milliamp RCD. Can you concentrate
> on the topic rather than posting feeling and myths generated by ignorance?
> Why do you routinely and repeatedly ignore the OP's problem? Why do you
> subvert this thread by promoting unacceptable designs and obsolete
> standards? Can you assist the OP?

This thread is subverted by you when the OP was asking about a 100mA
RCD. Do keep up rather than showing your ignorance, or even a lack of
comprehension skills.

[spuorg...@gowanhill.com]

On Thursday, 12 November 2015 18:30:23 UTC, Peter Parry wrote:
> The population of the USA is about 6 times that of the UK. In the
> year 2009 about 100 Americans died due to electrocution in the home
> from consumer products alone.

And that's just in the home.

Prisons in Alabama, Florida, South Carolina, Virginia, Kentucky, Tennessee, Arkansas and Oklahoma are also rather high risk.

Owain

[spuorg...@gowanhill.com]

On Thursday, 12 November 2015 19:30:09 UTC, Adam Funk wrote:
> > You have extension leads with 20 things plugged in to them from one
> > socket!
> Not directly, of course: you daisy-chain the extension leads.

No need to daisy-chain; up to 20 sockets here:

http://www.olson.co.uk/left_right_cables.htm

Owain

[John Rumm]

On 12/11/2015 19:44, westom wrote:

> replying to Peter Parry , westom wrote:
>> peter wrote:
>> You have extension leads with 20 things plugged in to them from one
>> socket!
>
> Again, your knowledge is only of local wiring standards using inferior
> protection.

No, we are well aware that wiring in the US is generally crap. Crap
electrical accessories, use of Ali cables, wire nuts etc... shudder!

> Informed engineers routinely design equipment to leak less than 100

Please try and get a clue. Go look at the specification of a typical RFI
suppressor and explain how you are going to design your equipment to
have a leakage of less than zero!

> You again subvert this thread with what is totally irrelevant. OP has a
> fault so serious as to even trip a 100 milliamp RCD. Can you concentrate

Is readin not your strong point? The OP said (and I quote verbatim):

"an electrician installed a whole installation 30mA RCD recently"

That is what is tripping, not a 100mA RCD.

> Why do you routinely and repeatedly ignore the OP's problem? Why do you
> subvert this thread by promoting unacceptable designs and obsolete
> standards? Can you assist the OP?

Because we can read.

[Peter Parry]

On Thu, 12 Nov 2015 19:44:01 +0000, westom
<caedfaa9ed1216d60e...@example.com> wrote:

>replying to Peter Parry , westom wrote:


>20 appliances on many receptacles can and must be powered by one RCD that
>will trip on 5 milliamps.

Why?

>You should have known that long before denying
>and posting. Many appliances on one 5 milliamp RCD is routine in venues
>where human safety is better.

Better than what? The US standards are dire. Very few are
International standards because no one is willing to downgrade to meet
them.

If they are so good why do so many more people in the USA (as a
proportion of population) die of electrocution than in the UK?

I presume the "venues" you are wittering on about are Wally's burger
bar?

>Informed engineers routinely design equipment to leak less than 100
>microamps. A 3.5 milliamp leakage is unacceptable in venues where better
>safety exists.

Name some (and when you do, remember how many more people are
electrocuted at work and at home in the USA than in the UK).

>Properly designed equipment must work without tripping any
>RCD anywhere in the world - even on construction sites. 20 items, each
>leaking 3.5 milliamps, is unsafe, unacceptable, and routinely avoided by
>simple and proven designs.

There are no documented cases of anyone being killed or injured by a
circuit protected by a 30mA RCD.

>You again subvert this thread with what is totally irrelevant. OP has a
>fault so serious as to even trip a 100 milliamp RCD.

No it doesn't, as you have been told several times by others. He
hasn't fitted a 100mA RCD.

[Adam Funk]

I haven't seen those before, but I've seen plenty of situations where
they would have been useful!

[Adam Funk]

On 2015-11-13, Huge wrote:

> Olson stuff is awesome. It's often available on ebay, and I have 4 large
> strips in my study, totalling 76 sockets ...

Your RCDs must be tripping all the time.... ;-)

[Fredxxx]

Thankfully much equipment is double insulated associated with leakage
currents only Mr Westom can dream about.

I doubt the sockets will be fully populated!

[ARW]

"Fredxxx" <fre...@nospam.com> wrote in message

news:n22tag$7fn$1...@dont-email.me...

Either from the Connections mag or similar. Backed up by my manager.

>>> Was the Ze issue a supply issue or an earth spike issue?
>>
>> Supply issue - both were PME.
>
> I was intrigued - thanks. What was the result, a rapid change to TT?

Fuck no. Roads dug up at 11pm the same night on one of them:-) Took them 3
day to fix that one as it also affected quite a few houses.


--
Adam