Mains changeover switch to generator backup

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David

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Dec 3, 2021, 3:51:47 PM12/3/21
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Prompted by the power cut thread.

As far as I can tell if you want to be able to power your home from a
generator if the mains power goes off then you need a changeover switch to
isolate the mains before you fire up the generator.

A quick and nasty search of Amazon suggests that these may not be very
expensive - perhaps around £100.

You would presumably then need an approved installation to provide a feed
in from the generator and a guaranteed isolation from the mains.
I assume a competent electrician could do this.

Any feeling for the cost of this installation?

Dodgy calculation suggests that a 60A mains feed would require roughly 13
kW of generator power to maintain supply, but I am assuming that this
would not be the aim.
Target to be able to run the fridge and freezer, lights, and central
heating pump and controls.

Electric fires, electric cookers etc. not catered for.

If power is out then the internet is presumably out as well, and probably
mobile phones, so basic amenities only required.

Cheers


Dave R



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Brian

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Dec 3, 2021, 5:04:27 PM12/3/21
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David <wib...@btinternet.com> wrote:
> Prompted by the power cut thread.
>
> As far as I can tell if you want to be able to power your home from a
> generator if the mains power goes off then you need a changeover switch to
> isolate the mains before you fire up the generator.
>
> A quick and nasty search of Amazon suggests that these may not be very
> expensive - perhaps around £100.
>
> You would presumably then need an approved installation to provide a feed
> in from the generator and a guaranteed isolation from the mains.
> I assume a competent electrician could do this.
>
> Any feeling for the cost of this installation?
>
> Dodgy calculation suggests that a 60A mains feed would require roughly 13
> kW of generator power to maintain supply, but I am assuming that this
> would not be the aim.
> Target to be able to run the fridge and freezer, lights, and central
> heating pump and controls.
>
> Electric fires, electric cookers etc. not catered for.
>
> If power is out then the internet is presumably out as well, and probably
> mobile phones, so basic amenities only required.
>
> Cheers
>
>
> Dave R
>
>
>

To run just ‘essentials’ ( keeping fridges / freezers going - although the
latter will be ok for a reasonable time- lights, ch pump, perhaps a tv,
computer etc, you don’t need a huge generator. Remember, not everything
needs to be run at once. You can even have the generator converted to run
on gas. I run mine on propane but I could run it on natural gas.

As for change over switches. They are easily available - manual and
automatic. Some motorhome people fit them either to use with generators or
inverters.

Owain Lastname

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Dec 3, 2021, 5:23:33 PM12/3/21
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On Friday, 3 December 2021 at 20:51:47 UTC, David WE Roberts (Google) wrote:
> As far as I can tell if you want to be able to power your home from a
> generator if the mains power goes off then you need a changeover switch to
> isolate the mains before you fire up the generator.

The difficulty is arranging load shedding so that unnecessary circuits are locked out when in generator mode.

And during a power cut you cannot rely on the supplier's earth so you may have to add a TT earth in conjuction with TN-S or TN-C-S (PME) from the supplier.

Owain

ARW

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Dec 4, 2021, 2:17:54 AM12/4/21
to
On 03/12/2021 20:51, David wrote:
> Prompted by the power cut thread.
>
> As far as I can tell if you want to be able to power your home from a
> generator if the mains power goes off then you need a changeover switch to
> isolate the mains before you fire up the generator.
>
> A quick and nasty search of Amazon suggests that these may not be very
> expensive - perhaps around £100.
>
> You would presumably then need an approved installation to provide a feed
> in from the generator and a guaranteed isolation from the mains.
> I assume a competent electrician could do this.

I used

https://www.screwfix.com/p/abb-32a-2p-e-inlet-250v/9071x

outside on the last domestic genny supply I fitted and used 6mm T&E from
it to the changeover switch.

I them made up an appropriate lead using arctic flex (with a NE link in
it and fitted an earth rod.

Customer would then wheel the genny out the garage and plug it in when
required. It could run their oven or a ring or two on the cooker.
Electric fires not needed as the gas CH should still be on

--
Adam

Theo

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Dec 4, 2021, 4:43:10 AM12/4/21
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Owain Lastname <spuorg...@gowanhill.com> wrote:
> On Friday, 3 December 2021 at 20:51:47 UTC, David WE Roberts (Google) wrote:
> > As far as I can tell if you want to be able to power your home from a
> > generator if the mains power goes off then you need a changeover switch to
> > isolate the mains before you fire up the generator.
>
> The difficulty is arranging load shedding so that unnecessary circuits are
> locked out when in generator mode.

It would be possible to put the changeover downstream of the CU, so you're
only feeding a specific circuit rather than all of them. But the problem is
often that the circuits aren't laid out nicely, and there will be some loads
on them that might cause issues - for example heaters or hot water on
timers, as well as inrush current to SMPSUs. Those might trip a generator
if they weren't locked out. Also there may be standby loads you don't want
to power.

Another option would be to run a separate circuit for loads that want to be
run in generator mode, but that would be disruptive. I wonder if you could
do something instead with smart switches?

Theo

Brian Gaff (Sofa)

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Dec 4, 2021, 5:33:02 AM12/4/21
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I see no o reason not to keep the internet router and a low power computer
of some kind. Hardly high wattage compared to heating and cooking. You might
dedicate a separate ring for such devices and only have to switch that so
there is no problem with needing some huge switch.
I think I'd stick to a manual switch system, obviously break before make is
needed.
Brian

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Nick Odell

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Dec 4, 2021, 5:38:39 AM12/4/21
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On Sat, 4 Dec 2021 09:14:02 -0000 (UTC), Jethro_uk
<jeth...@hotmailbin.com> wrote:
>Don't forget to check and test it ... monthly ? Weekly ?
>
>Back in the 70s, my Dad rigged up a series of car batteries that drove
>the gas CH and some 12V workshop lights through the house. I remember him
>reminding my Mum to keep them charged when the power was on.

I'm not your dad am I?

Back in the 70s when power cuts were almost daily occurences I had to
rewire our house and so I took the opportunity to put in a parallel
12v system powered by car batteries stored under the floor in the
cupboard-under-the-stairs.

I like to think that I single-handedly solved the UK energy problem
because once the 12v system was up and running we didn't have another
power cut for years.

Nick

ARW

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Dec 4, 2021, 11:44:01 AM12/4/21
to
On 04/12/2021 09:43, Theo wrote:
> Owain Lastname <spuorg...@gowanhill.com> wrote:
>> On Friday, 3 December 2021 at 20:51:47 UTC, David WE Roberts (Google) wrote:
>>> As far as I can tell if you want to be able to power your home from a
>>> generator if the mains power goes off then you need a changeover switch to
>>> isolate the mains before you fire up the generator.
>>
>> The difficulty is arranging load shedding so that unnecessary circuits are
>> locked out when in generator mode.
>
> It would be possible to put the changeover downstream of the CU, so you're
> only feeding a specific circuit rather than all of them.


How? I cannot visualise this at all. Enlighten me please.

--

Adam

Mark Carver

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Dec 4, 2021, 11:53:29 AM12/4/21
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By killing all the breakers on the CU, and connecting the generator to a
13A socket (or whatever) on just a single circuit ?

The breakers would need to be double pole, or it could get 'tricky' ?

(None of that would be regs compliant of course)

ARW

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Dec 4, 2021, 12:03:32 PM12/4/21
to
On 04/12/2021 09:43, Theo wrote:

> Another option would be to run a separate circuit for loads that want to be
> run in generator mode, but that would be disruptive.

That is sort of what I did at my parents for there pure sine wave inverter.

There is a 12V car battery that they keep charged in the garage powers
the inverter. The then connect the extension lead I made and run it
across the garden to an inlet as in my earlier post. On the inside of
the house at the back of the inlet is a socket that only becomes live
when this is done.

There is then another extension lead to run out from this socket with
sockets on it at appropriate places such as a couple of table lamps, TV
and finally the boiler that I swapped it's supply from a switched fused
spur to a unswitched socket.

It gives them light, TV, heat (and as it's a combi HW) and just enough
juice to power a travel kettle or the microwave on a 700W setting for
long enough to make a brew or hot meal. The battery will of course not
last long - however they can recharge it from their cars in the garage.

The idea of this one was not for long term power cuts with 24/7 power
but to heat the house have a cup of tea and something warm to eat and if
Emley Moor is still broadcasting watch shit on the TV.

The main thing in their case was to keep the house warm and keep the
lights on. It could also probably give the freezers a boost if needed.

--

Adam

Rod Speed

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Dec 4, 2021, 12:04:44 PM12/4/21
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ARW <adamwa...@blueyonder.co.uk> wrote
> Theo wrote
>> Owain Lastname <spuorg...@gowanhill.com> wrote
>>> David WE Roberts (Google) wrote

>>>> As far as I can tell if you want to be able to power your home from a
>>>> generator if the mains power goes off then you need a changeover switch
>>>> to
>>>> isolate the mains before you fire up the generator.
>>>
>>> The difficulty is arranging load shedding so that unnecessary circuits
>>> are
>>> locked out when in generator mode.
>>
>> It would be possible to put the changeover downstream of the CU, so
>> you're
>> only feeding a specific circuit rather than all of them.
>
>
> How? I cannot visualise this at all. Enlighten me please.

Have the changeover on one of the circuits after the CU.

You are having a brain fart.

Rod Speed

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Dec 4, 2021, 12:06:49 PM12/4/21
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Mark Carver <mark....@invalid.invalid> wrote
> ARW wrote
>> Theo wrote
>>> Owain Lastname <spuorg...@gowanhill.com> wrote
>>>> David WE Roberts (Google) wrote

>>>>> As far as I can tell if you want to be able to power your home from a
>>>>> generator if the mains power goes off then you need a changeover
>>>>> switch to
>>>>> isolate the mains before you fire up the generator.
>>>>
>>>> The difficulty is arranging load shedding so that unnecessary
>>>> circuits are
>>>> locked out when in generator mode.
>>>
>>> It would be possible to put the changeover downstream of the CU, so
>>> you're
>>> only feeding a specific circuit rather than all of them.
>>
>>
>> How? I cannot visualise this at all. Enlighten me please.
>>
>
> By killing all the breakers on the CU, and connecting the generator to a
> 13A socket (or whatever) on just a single circuit ?
>
> The breakers would need to be double pole, or it could get 'tricky' ?

Just have the changeover after the breaker.

> (None of that would be regs compliant of course)

His way would be.

ARW

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Dec 4, 2021, 12:15:56 PM12/4/21
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I was thinking of regs compliant!


--

Adam

Peeler

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Dec 4, 2021, 1:47:54 PM12/4/21
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"Rod Speed is an entirely modern phenomenon. Essentially, Rod Speed
is an insecure and worthless individual who has discovered he can
enhance his own self-esteem in his own eyes by playing "the big, hard
man" on the InterNet."

https://www.pcreview.co.uk/threads/rod-speed-faq.2973853/

--
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"You are an insecure blathermouth with an inferiority complex."
MID: <j08dic...@mid.individual.net>

Peeler

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Dec 4, 2021, 1:51:08 PM12/4/21
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On Sun, 5 Dec 2021 04:04:37 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

<FLUSH the abnormal trolling senile cretin's latest trollshit unread>

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Mike Humphrey

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Dec 4, 2021, 3:47:27 PM12/4/21
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That's quite straightforward. Disconnect the circuit from its circuit
breaker, and wire it instead to the output of the changeover switch. Wire
one input of the changeover switch back to the breaker in the CU. Wire
the other input to the generator.

When the power goes off, move the switch over. That circuit is now
connected to the generator (and not the mains). Everything else is still
connected to the mains (only) and so is dead until power is restored.
There's no cross-connection as the mains input of the switch is isolated
from the generator input.

Perfectly regs compliant as long as you remember:
- provide a local earth rod
- RCD on the generator circuit (you're now running TT earthing)
- MCB suitable for the circuit on the generator feed (or an RBCO to also
address the point above)
- the required warning label about multiple supplies.

You could also go for an in-between option - split the supply to two CUs.
One is fed direct from the mains, the other via the changeover switch.
This allows you to have lights on a separate circuit to the boiler etc
while still having both fed from the generator when needed.



Mike

Fredxx

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Dec 5, 2021, 5:40:13 AM12/5/21
to
On 04/12/2021 20:47, Mike Humphrey wrote:
> On Sat, 04 Dec 2021 16:43:56 +0000, ARW wrote:
>> On 04/12/2021 09:43, Theo wrote:
>>> It would be possible to put the changeover downstream of the CU, so
>>> you're only feeding a specific circuit rather than all of them.
>
>>
>> How? I cannot visualise this at all. Enlighten me please.
>
> That's quite straightforward. Disconnect the circuit from its circuit
> breaker, and wire it instead to the output of the changeover switch. Wire
> one input of the changeover switch back to the breaker in the CU. Wire
> the other input to the generator.
>
> When the power goes off, move the switch over. That circuit is now
> connected to the generator (and not the mains). Everything else is still
> connected to the mains (only) and so is dead until power is restored.
> There's no cross-connection as the mains input of the switch is isolated
> from the generator input.
>
> Perfectly regs compliant as long as you remember:
> - provide a local earth rod

Is this still necessary where the incomer is TN* variety? As long as the
earth is experted to the generator.[1]

> - RCD on the generator circuit (you're now running TT earthing)

Most Consumer units will be wholly RCD protected, or even RCBO. Does the
generator need another?

> - MCB suitable for the circuit on the generator feed (or an RBCO to also
> address the point above)
> - the required warning label about multiple supplies.

> You could also go for an in-between option - split the supply to two CUs.
> One is fed direct from the mains, the other via the changeover switch.
> This allows you to have lights on a separate circuit to the boiler etc
> while still having both fed from the generator when needed.

I might at least suggest a visual means of knowing power had been restored.

[1] In the case of a known neutral fault then obviously this won't work.
and the earth will need to be isolated from the network.

Dave Plowman (News)

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Dec 5, 2021, 7:01:56 AM12/5/21
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In article <sog5sc$mfs$1...@dont-email.me>,
It's what I've done with the inverter which only feeds the boiler radial.

Used a changeover relay which disconnects it from the CU, and connects to
the inverter output.

--
*Laugh alone and the world thinks you're an idiot.

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

Rod Speed

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Dec 5, 2021, 10:30:40 AM12/5/21
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Fredxx <fre...@nospam.co.uk> wrote
> Mike Humphrey wrote
>> ARW wrote
I normally find that I can hear the mains return when various stuff starts
up when the mains comes back even when that happens in daytime.

Don’t even need that at night given that the room lights come back then.

Bigger problem with the broadband dropping out for hours given that
I have been using the phone as a hotspot while the broadband is down.

With my current config, I normally turn the router off because
the desktop PC running Win7 gets confused when it has the
router running with no broadband and the hotspot visible.

Andrew

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Dec 5, 2021, 11:16:52 AM12/5/21
to
On 04/12/2021 20:47, Mike Humphrey wrote:
> On Sat, 04 Dec 2021 16:43:56 +0000, ARW wrote:
>> On 04/12/2021 09:43, Theo wrote:
>>> It would be possible to put the changeover downstream of the CU, so
>>> you're only feeding a specific circuit rather than all of them.
>
>>
>> How? I cannot visualise this at all. Enlighten me please.
>
> That's quite straightforward. Disconnect the circuit from its circuit
> breaker, and wire it instead to the output of the changeover switch. Wire
> one input of the changeover switch back to the breaker in the CU. Wire
> the other input to the generator.
>

>

Just use these :-)

https://en.wikipedia.org/wiki/Knife_switch

Peeler

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Dec 5, 2021, 12:08:13 PM12/5/21
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On Mon, 6 Dec 2021 02:30:33 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

<FLUSH the abnormal trolling senile cretin's latest trollshit unread>

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John J

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Dec 6, 2021, 3:59:19 AM12/6/21
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Maybe it would be an option (granted more work involved) to have a second consumer unit serving only critical circuits such as boiler, lights and a suitably placed socket(s) for kettle, and IT equipment? A changeover switch of sufficient rating between this and the primary consumer unit would enable easy connection of an alternative supply in the event of a power cut.
I used to have an old 30 Amp 3 pole MEM ironclad changeover switch lying about in the shed but it went missing years ago.
Our oil boiler and controls are connected by a 13A plug so I have the option of dragging out the generator to outside the window and feeding the oil heating via an extension lead if a power cut looks like dragging on for an extended period. Being sans mains gas we've currently got a propane gas fire and gas hob for cooking if required as my geny is only 1 kW so an electric kettle wouldn't be practical unless I bought a bigger geny.
I've not looked into the inverter options but oil boilers do take a brief higher current demand during the ignition phase which might be more than cheap inverters can handle?

John Rumm

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Dec 6, 2021, 9:04:36 AM12/6/21
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On 05/12/2021 10:40, Fredxx wrote:
> On 04/12/2021 20:47, Mike Humphrey wrote:
>> On Sat, 04 Dec 2021 16:43:56 +0000, ARW wrote:
>>> On 04/12/2021 09:43, Theo wrote:
>>>> It would be possible to put the changeover downstream of the CU, so
>>>> you're only feeding a specific circuit rather than all of them.
>>
>>>
>>> How? I cannot visualise this at all. Enlighten me please.
>>
>> That's quite straightforward. Disconnect the circuit from its circuit
>> breaker, and wire it instead to the output of the changeover switch. Wire
>> one input of the changeover switch back to the breaker in the CU. Wire
>> the other input to the generator.
>>
>> When the power goes off, move the switch over. That circuit is now
>> connected to the generator (and not the mains). Everything else is still
>> connected to the mains (only) and so is dead until power is restored.
>> There's no cross-connection as the mains input of the switch is isolated
>> from the generator input.
>>
>> Perfectly regs compliant as long as you remember:
>> - provide a local earth rod
>
> Is this still necessary where the incomer is TN* variety? As long as the
> earth is experted to the generator.[1]

With TN-C-S and a loss of supply, it is possible to lose the combined
Neutral and Earth as well (imagine a tree bringing down a LV overhead
wire). That could leave your main earth terminal floating.

(typically they use PME with multiple earth connections along the route
to try an ensure this never happens)

Likewise a TN-S setup could get cut and you lose the separate earth
connection to the substation. (although depending on where the cut is,
the cable sheath alone might make a reasonable TT earth if it's an old
metal clad cable)

>> - RCD on the generator circuit (you're now running TT earthing)
>
> Most Consumer units will be wholly RCD protected, or even RCBO. Does the
> generator need another?

Not necessarily... unless you need to protect the main feed from the
generator against earth faults.

>> - MCB suitable for the circuit on the generator feed (or an RBCO to also
>> address the point above)
>> - the required warning label about multiple supplies.
>
>> You could also go for an in-between option - split the supply to two CUs.
>> One is fed direct from the mains, the other via the changeover switch.
>> This allows you to have lights on a separate circuit to the boiler etc
>> while still having both fed from the generator when needed.
>
> I might at least suggest a visual means of knowing power had been restored.
>
> [1] In the case of a known neutral fault then obviously this won't work.
> and the earth will need to be isolated from the network.

Earth connections should not generally be "switchable". If going the
separate CU route then making that whole CU TT might be an option (if
possible - it can be tricky when you introduce main bonds to water
supplies etc if they are in metal pipes - you might just find you have
got a defacto TN-C-S earth again via someone else's TN-C-S neutral earth
bond).

--
Cheers,

John.

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

tony sayer

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Dec 6, 2021, 1:14:14 PM12/6/21
to
In article <soe497$rkv$1...@dont-email.me>, Brian <no...@lid.org> scribeth
thus
Https://www.tlc-direct.co.uk/Products/CGM125CS.html

or

https://www.tlc-direct.co.uk/Products/CGCS1004P.html

JFK Electrical have them on Amazon cant do a link;(..
07962109794
137 Bush Road
coalisland
Dungannon
Tyrone
BT71 6QQ
GB


--
Tony Sayer


Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.


ARW

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Dec 6, 2021, 5:11:04 PM12/6/21
to
On 06/12/2021 08:59, John J wrote:
> On Saturday, 4 December 2021 at 16:44:01 UTC, ARW wrote:
>> On 04/12/2021 09:43, Theo wrote:
>>> Owain Lastname <spuorg...@gowanhill.com> wrote:
>>>> On Friday, 3 December 2021 at 20:51:47 UTC, David WE Roberts (Google) wrote:
>>>>> As far as I can tell if you want to be able to power your home from a
>>>>> generator if the mains power goes off then you need a changeover switch to
>>>>> isolate the mains before you fire up the generator.
>>>>
>>>> The difficulty is arranging load shedding so that unnecessary circuits are
>>>> locked out when in generator mode.
>>>
>>> It would be possible to put the changeover downstream of the CU, so you're
>>> only feeding a specific circuit rather than all of them.
>> How? I cannot visualise this at all. Enlighten me please.
>>

> Maybe it would be an option (granted more work involved) to have a second consumer unit serving only critical circuits such as boiler, lights and a suitably placed socket(s) for kettle, and IT equipment? A changeover switch of sufficient rating between this and the primary consumer unit would enable easy connection of an alternative supply in the event of a power cut.

Yes that is one option


> I used to have an old 30 Amp 3 pole MEM ironclad changeover switch lying about in the shed but it went missing years ago.
> Our oil boiler and controls are connected by a 13A plug so I have the option of dragging out the generator to outside the window and feeding the oil heating via an extension lead if a power cut looks like dragging on for an extended period. Being sans mains gas we've currently got a propane gas fire and gas hob for cooking if required as my geny is only 1 kW so an electric kettle wouldn't be practical unless I bought a bigger geny.
> I've not looked into the inverter options but oil boilers do take a brief higher current demand during the ignition phase which might be more than cheap inverters can handle?
>
https://www.tlc-direct.co.uk/Products/SK652104.html

And that has

Short circuit, overload and overheat protection

and

Please note: Ensure the device is well within the inverter output power
rating. We recommend using an inverter capable of supplying a minimum of
3 times the device's rated power to avoid damage to the inverter by any
current surge (especially for fridges and freezers which can surge up to
7 times the rated power)




Mike Humphrey

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Dec 6, 2021, 7:32:40 PM12/6/21
to
On Sun, 05 Dec 2021 10:40:08 +0000, Fredxx wrote:
> On 04/12/2021 20:47, Mike Humphrey wrote:
>> Perfectly regs compliant as long as you remember:
>> - provide a local earth rod
>
> Is this still necessary where the incomer is TN* variety? As long as the
> earth is experted to the generator.[1]

The regs say it is. After all, the power cut could be caused by the cable
being cut just outside your house, which would cut the earth as well. Or
even the cable being deliberately removed (to replace it, for example).

>> - RCD on the generator circuit (you're now running TT earthing)
>
> Most Consumer units will be wholly RCD protected, or even RCBO. Does the
> generator need another?

The setup I described had one circuit fed from the generator not passing
through the CU. In this case you would need another RCD (or RCBO). If the
generator supply passes through the CU RCD, then you don't need to add
another one. But you do need RCD protection on every circuit, as your
generator is TT earthing - if your CU only has RCDs on some circuits, you
either need to add more RCDs/RCBOs or put a time delay RCD in front of it.

> I might at least suggest a visual means of knowing power had been
> restored.

Yes, that's the downside of putting everything behind the changeover
switch - you can't see when the power comes back.

Mike

John J

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Dec 7, 2021, 3:32:26 AM12/7/21
to
Perhaps worth mentioning the input DC current (ignoring efficiency/losses) of a 12 supply from a battery will be around 20 times greater than that delivered to a 240 volt load - not something a typical battery will sustain for long. Hence my preference for a generator.

tony sayer

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Dec 7, 2021, 9:16:35 AM12/7/21
to
>The idea of this one was not for long term power cuts with 24/7 power
>but to heat the house have a cup of tea and something warm to eat and if
>Emley Moor is still broadcasting watch shit on the TV.
>
>The main thing in their case was to keep the house warm and keep the
>lights on. It could also probably give the freezers a boost if needed.
>
>--
>
>Adam

I've been told that the transmitters at Emley Moor are on fuck off size
UPS units to keep on air whilst the gennies start up!...

ARW

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Dec 7, 2021, 12:36:55 PM12/7/21
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On 07/12/2021 12:10, tony sayer wrote:

>
> I've been told that the transmitters at Emley Moor are on fuck off size
> UPS units to keep on air whilst the gennies start up!...
>

So are the essential circuits at Doncaster Royal Infirmary.

--

Adam

ARW

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Dec 7, 2021, 1:06:22 PM12/7/21
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On 07/12/2021 08:32, John J wrote:

> Perhaps worth mentioning the input DC current (ignoring efficiency/losses) of a 12 supply from a battery will be around 20 times greater than that delivered to a 240 volt load - not something a typical battery will sustain for long. Hence my preference for a generator.
>

My Dad would fork out for a 7/8kW genny with electric start and a
changeover switch tomorrow. The inverter was all my Mum would allow him
to have and she was not happy about that. She cannot see the need.

Your point about DC losses and the battery not lasting very long are
noted. Thank you.

However my parents have two cars sat in the garage next to the inverter
that they can use top up power up if needed. It was never a 24/7
solution but it could run the CH for a few hours a couple of times a day
and keep a couple of table lamps on for several hours before they needed
to top up. As they are not in rural Aberdeenshire hopefully they will
never go 3 days without electricity.

For some reason your post has reminded me that I am going to have to get
laminated instructions how to use the inverter printed off for them or
for a neighbour to be able to do it for them. My Dad is getting a little
forgetful and my Mum has no interest in it.

Cheers

--

Adam
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