Garden cabling / electricity
Dundonald
which inolved building a partition wall, filling in with hardcore and
top soil to level everything off, followed by returfing everywhere. I
requested cabling to be inserted so I can have an electrician hook up
some garden lighting and connect to the cabling to our mains. Thing is
the gardner has simply laid the cabling underneath the turf so what's
that - about an inch and a half deep at most.
I'm no sparky and I'm concerned this isn't the best idea and when I do
have a sparky come around to do the legit work and hook everything up
they wont touch it.
Am I being overly sensitive? What are the regs?
jd
If I was you I'd get on the phone to your landscape gardener and ask
him to relay the cable properly. What he's done is probably more
dangerous than just laying it across the surface of the grass - at
least then you would SEE it before being electrocuted. I'm not sure
what the regulations are, but I laid my armoured cable about 18 inches
below the surface and the spark I used to connect it up seemed happy
(ish) - maybe another six inches deeper would have been better!
Dundonald
Did you lay your cable in some form of tubing?
Stefek Zaba
>>
>>Am I being overly sensitive? What are the regs?
No; and see below, in that order ;-)
> If I was you I'd get on the phone to your landscape gardener and ask
> him to relay the cable properly. What he's done is probably more
> dangerous than just laying it across the surface of the grass - at
> least then you would SEE it before being electrocuted. I'm not sure
> what the regulations are, but I laid my armoured cable about 18 inches
> below the surface and the spark I used to connect it up seemed happy
> (ish) - maybe another six inches deeper would have been better!
>
For a lawn, 18 inches is reasonable. The Regs don't lay down a precise
depth, but say sthg like 'beyond reasonably foreseeable digging depth'.
That's widely accepted to be about 18inches in 'normal' bits of a
garden, being 2 spade depths (so 'normal' digging won't touch it, and
even full-on double-digging - wot I remember doing to very good effect
in the end of the thankfully postage-stamp-sized garden in our first
house!) will hit the "WARNING - BURIED ELECTRICAL CABLE BELOW" yellow
warning tape and the bit of pea gravel the cable's laid in - these being
the accepted form of Good Workmanship for buried cable.
Just below the turf is - as jd says - a *really* poor idea. It would be
considerably better to run the cable - assuming it's SWA (steel wire
armoured) which is what you need for direct burial - securely clipped
*above* ground, if there's a wall or robust fence (former is A-OK in
Regs-land, latter gets rapidly iffier the more rickety the fence is!).
That way it's clear where the cable is, rather than waiting for a spade
or minidigger to Discover the cable...
Whether the OP's landscape gardener should be expected to know about
cable-laying practices is not completely clear to me - if they advertise
themselves as a full-service garden landscaping outfit and said 'yeah
yeah' to the cable idea, they should have known how to do the job
properly; if it's a jobbing gardener working under the explicit
instructions of the OP without claiming any expertise, it's less
definite, I'd guess...
Stefek
jd
not sure but I think you only need to use conduits if it is
non-armoured. As Stefek has mentioned in his post, maybe you could
simply run it above ground. But before doing that, maybe you should
watch that episode of Curb Your Enthusiasm about the above ground
cable.....
ShirKahn
Just as an extra thought- once you have the cable reburied correctly-
make a rough sketch of your garden and mark on it where you burried
the cable with some measurements from immobile reference points, like
the corner of the house etc. Put this in a ziplock baggie and hang it
on the wall next to your breaker box. Since markers will get lost
over the years and memories do get a little fuzzy- this should make
sure that if you need to do some digging in the area at some future
date nobody gets a suprise or you don't accidently create more work
for yourself by having to splice/repair a damaged power line.
-chris
Alan
"Dundonald" <mark....@gmail.com> wrote in message
news:1111346289.9...@z14g2000cwz.googlegroups.com...
Is the cable he laid armoured (SWA) or standard twin & earth stuff?
If standard T&E then pull it out now - this should not be used!!
Alan.
Dundonald
I haven't checked the cable yet, it hasn't yet been connected so it's
not live, but I'm guessing it's twin and earth because it was only
£1.50 a metre (so the gardner says).
Lobster
> Whether the OP's landscape gardener should be expected to know about
> cable-laying practices is not completely clear to me - if they advertise
> themselves as a full-service garden landscaping outfit and said 'yeah
> yeah' to the cable idea, they should have known how to do the job
> properly
Aren't we in Part P territory here anyway (like a gardener's even going
to know that exists!)
David
Mathew J. Newton
> > Is the cable he laid armoured (SWA) or standard twin & earth stuff?
> >
> > If standard T&E then pull it out now - this should not be used!!
>
> I haven't checked the cable yet, it hasn't yet been connected so it's
> not live, but I'm guessing it's twin and earth because it was only
> £1.50 a metre (so the gardner says).
That price suggests SWA, or you've been ripped off.
Mathew
Dundonald
It is only my very uneducated guess that it was twin and earth because
I've no experience of electricity cable.
I'll check the cable tonight see if I can make it out.
Mathew J. Newton
The following URLs may be of help:
http://www.tlc-direct.co.uk/Main_Index/Cable_Index/Twin_and_Earth/index.html
http://www.tlc-direct.co.uk/Main_Index/Cable_Index/Armoured_SWA/index.html
and even
http://www.tlc-direct.co.uk/Main_Index/Cable_Index/Hi-Tuf/index.html
if he's used HiTuf.
Mathew
Dundonald
Thanks for all your replies. I'm replying to my original post on 24th
March with a couple further questions after consideration of posts so
far and further study by myself.
1. My original post insinuated that 240v from the mains would be
carried around the cable. If you read through the thread and posts so
far the general consus is that this cabling is not sufficient for this
purpose. I definately agree this cabling (it is by the way twin and
earth looping around) is not sufficient or safe by a long way if I spur
it directly off a mains - i.e. carrying 240v. However I've done some
further studies and if I spur off a mains, hook it up to a 5A fuse box
then through a transformer down to 12v would this be acceptable? i.e.
the twin and earth that has simply been laid underneath the turf around
the garden would only carry 12v - sufficient enough to power garden
lighting? Please correct me where I'm wrong, I'm still learning about
all this stuff, but as I understand it you can buy garden lighting that
are already connected with thin wire and the plug has a built in
transformer converting 240v down to 12v for the lighting. This thin
wire is usually laid above ground. So again I'm assuming that twin and
earth wire laid a couple inches below ground also carrying 12v should
be safe also?
2. The second question I had related to the water feature our gardener
has installed. The cable to the pump is separate to that cable I
explain above, but it too has also been laid under the new turf, so
again only a couple inches below ground at most. I have inspected the
pump and the cable in to the pump is underwater (along with the pump).
Is this normal? The cable looks like it was already connected to the
pump, it looks again like twin and earth. I wasn't around when the
gardener installed this but he suggested to my wife that a plug can be
attached to the end of the cable so it can be plugged in to the mains
just to test the pump. So my wife did that. We have only ever plugged
the water feature in for a few minutes at most. But obviously this
would mean that 240v is going through this cable, through what looks
like twin and earth, just two inches below ground. I am concerned
about that. So the questions I have about this then are 1. why is cable
in the pump under water, 2. can I do something similar to the lights
and run 12v to the pump instead of 240 and that way I can also use the
existing cable the way it is? If not I'll definately lay armoured
cable 18 inches below ground with warning tape above it etc..
Many thanks for your patience and help!
Owain
> 1. My original post insinuated that 240v from the mains would be
> carried around the cable. If you read through the thread and posts so
> far the general consus is that this cabling is not sufficient for this
> purpose. I definately agree this cabling (it is by the way twin and
> earth looping around) is not sufficient or safe by a long way if I spur
> it directly off a mains - i.e. carrying 240v. However I've done some
> further studies and if I spur off a mains, hook it up to a 5A fuse box
> then through a transformer down to 12v would this be acceptable? i.e.
> the twin and earth that has simply been laid underneath the turf around
> the garden would only carry 12v - sufficient enough to power garden
> lighting? Please correct me where I'm wrong, I'm still learning about
> all this stuff, but as I understand it you can buy garden lighting that
> are already connected with thin wire and the plug has a built in
> transformer converting 240v down to 12v for the lighting. This thin
> wire is usually laid above ground. So again I'm assuming that twin and
> earth wire laid a couple inches below ground also carrying 12v should
> be safe also?
It should be, but I would suggest using a proper garden lighting
transformer unit rather than something intended for LV halogen lamps
indoors, which might not be guaranteed to provide the necessary isolation.
At 12V however you will suffer voltage drop which will limit the demand
you can carry - 5A for example will only give you 60W of lighting.
Ordinary T&E is not designed for direct burial regardless of the voltage.
> 2. The second question I had related to the water feature our gardener
> has installed. The cable to the pump is separate to that cable I
> explain above, but it too has also been laid under the new turf, so
> again only a couple inches below ground at most. I have inspected the
> pump and the cable in to the pump is underwater (along with the pump).
> Is this normal?
It is normal for submersible pumps to have a length of *suitable* flex
already attached. This must be connected to the fixed wiring outside the
water by a *suitable* connection unit.
> The cable looks like it was already connected to the
> pump, it looks again like twin and earth.
If it is ordinary twin&earth this is stupidity bordering on the
criminally negligent. Most watertight cable glands work with circular
flex/cable and will not form a long-lasting dependable seal with T&E.
> I wasn't around when the
> gardener installed this but he suggested to my wife that a plug can be
> attached to the end of the cable so it can be plugged in to the mains
> just to test the pump.
What tests did he carry out on the wiring before connecting it to the mains?
> So my wife did that. We have only ever plugged
> the water feature in for a few minutes at most. But obviously this
> would mean that 240v is going through this cable, through what looks
> like twin and earth, just two inches below ground. I am concerned
> about that. So the questions I have about this then are 1. why is cable
> in the pump under water,
To get to the pump, which is also under water.
> 2. can I do something similar to the lights
> and run 12v to the pump instead of 240 and that way I can also use the
> existing cable the way it is?
You can run 12V (to a 12V pump, obviously) but the problem remains that
the cable is unsuitable and may not last very long. You may also find
that a 12V pump lacks sufficient oomph.
> If not I'll definately lay armoured
> cable 18 inches below ground with warning tape above it etc..
It really is the best way of doing it. To simplify wiring (subject to
maximim loads etc) you can run one length of cable to everything and use
X10 receivers in weatherproof boxes to switch individual things on and
off by remote control (coloured lights, synchronised fountains, Handel
on speakers concealed in the rockery, etc).
You would be well advised to ensure the wiring is inspected and tested
by a competent electrician before connecting up, whether or not you
intend to comply with Part P of the Building Regulations. You might
prefer to do the trenching and cable laying work and get an electrician
to supply and fit all the accessories.
Owain