Hello -

A relative has a small outbuilding that needs a general overhaul of its
electrical wiring, and I'm wondering if it could be DIY'd without coming
under Part P.

It's basically a small steel-framed barn that houses a couple of cars and a
couple of horses. There's no wiring in the horses' part. It's fed by a short
buried cable from the consumer unit in the house, which feeds a smaller
consumer unit in the barn. Things which need to be addressed include:
- Most of the sockets and switches are old, some are cracked. Some may be
exposed to rain during severe weather.
- A family of swifts has built a nest on top of the barn's consumer unit,
which needs to be replaced.
- Presumably the earthing requirements need to be looked at, particularly in
view of the amount of earthed steel around.
- I want to fix whatever needs fixing, but this would just be a repair
operation, not a sneaky extension or enhancement.

I have done lesser electrical tasks before, I have a physics/electronics
background, and am prepared to buy specialised testing kit. If I read up on
all the regulations and best practice, is this legitimately DIYable without
falling foul of Part P?

In article ,
"Simon" writes:
Hello -

A relative has a small outbuilding that needs a general overhaul of its
electrical wiring, and I'm wondering if it could be DIY'd without coming
under Part P.

No. All such wiring comes under Part P.
It's a separate question if you can self-certify or not though.

It's basically a small steel-framed barn that houses a couple of cars and a
couple of horses. There's no wiring in the horses' part. It's fed by a short
buried cable from the consumer unit in the house, which feeds a smaller
consumer unit in the barn. Things which need to be addressed include:
- Most of the sockets and switches are old, some are cracked. Some may be
exposed to rain during severe weather.
- A family of swifts has built a nest on top of the barn's consumer unit,
which needs to be replaced.
- Presumably the earthing requirements need to be looked at, particularly in
view of the amount of earthed steel around.

This is a very important issue, much more so because of the
horses. Tiny leakage currents which humans can barely feel
are fatal to most livestock including horses, so this has
to be got right. For this reason I strongly suggest you get
the work done by an electrician who is familiar with supplies
around farm livestock. There are issues here which domestic
electricians are unlikely to be very familiar with.

--
Andrew Gabriel

Andrew Gabriel wrote:
This is a very important issue, much more so because of the
horses. Tiny leakage currents which humans can barely feel
are fatal to most livestock including horses, so this has
to be got right.

Really? I didn't know that. What about electric fences for example?

I would have guessed that horses & cattle could have taken larger shocks
than humans because of thier greater mass. How does that work?

Just a thought.


--
Dave
The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

The message
from "The Medway Handyman" contains
these words:

This is a very important issue, much more so because of the
horses. Tiny leakage currents which humans can barely feel
are fatal to most livestock including horses, so this has
to be got right.

Really? I didn't know that. What about electric fences for example?

I would have guessed that horses & cattle could have taken larger shocks
than humans because of thier greater mass. How does that work?

The problem comes from the greater wheelbase on a horse. What may be a
trivial potential gradient for a biped can knock off a quadruped quite
easily. This is why lightning rod terminals are buried a foot or so down
- keeps the surface potential gradient down.

--
Skipweasel
Pay no attention to that man behind the curtain.

In article ,
"The Medway Handyman" writes:
Andrew Gabriel wrote:
This is a very important issue, much more so because of the
horses. Tiny leakage currents which humans can barely feel
are fatal to most livestock including horses, so this has
to be got right.

Really? I didn't know that. What about electric fences for example?

An electric fence is pulsed, and the animal has a choice to
move away from it. A leak from mains generally isn't pulsed.
It will create a potential difference across the ground where
it's earthed and the animal can't decide to let go of the ground
and may not have the knowledge or be too confined to move away.

I would have guessed that horses & cattle could have taken larger shocks
than humans because of thier greater mass. How does that work?

No, it's the opposite. In addition to the large wheelbase
problem which Guy mentions, it only needs a volt or two across
that to kill large animals, whereas a human would never have
any concern about touching the terminals of a 1.5V battery, or
even a 12V battery. This first showed up when a field of dead
animals was occasionally found with no explanation being obvious.
It has then been found that an insulator on an overhead wire is
leaking tiny amounts down the support pole, generating a small
potential difference across the ground not even noticable by
humans, but fatal to the livestock.

Someone on this newsgroup was involved with litigation resulting
from death of a horse due to earth leakage creating a small ground
potential, but I can't recall who it was.

--
Andrew Gabriel

On Tue, 12 Dec 2006 00:52:24 GMT someone who may be "The Medway
Handyman" wrote this:-

I would have guessed that horses & cattle could have taken larger shocks
than humans because of thier greater mass. How does that work?

In addition to what has been said, in a four legged animal the
current flowing between the front and back legs passes along the
main nervous system and thus may disrupt it. A human standing up
will not be affected by the potential gradient.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

David Hansen wrote:
On Tue, 12 Dec 2006 00:52:24 GMT someone who may be "The Medway
Handyman" wrote this:-

I would have guessed that horses & cattle could have taken larger shocks
than humans because of thier greater mass. How does that work?

In addition to what has been said, in a four legged animal the
current flowing between the front and back legs passes along the
main nervous system and thus may disrupt it. A human standing up
will not be affected by the potential gradient.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

The Medway Handyman wrote:
Andrew Gabriel wrote:
This is a very important issue, much more so because of the
horses. Tiny leakage currents which humans can barely feel
are fatal to most livestock including horses, so this has
to be got right.

Really? I didn't know that. What about electric fences for example?

I would have guessed that horses & cattle could have taken larger
shocks than humans because of thier greater mass. How does that work?

Just a thought.

Thanks chaps - I am a wiser man. How fascinating.


--
Dave
The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

The Medway Handyman wrote:
Andrew Gabriel wrote:
This is a very important issue, much more so because of the
horses. Tiny leakage currents which humans can barely feel
are fatal to most livestock including horses, so this has
to be got right.

Really? I didn't know that. What about electric fences for example?

I would have guessed that horses & cattle could have taken larger shocks
than humans because of thier greater mass. How does that work?

I think the major issue is simply that horses and cows are *longer*
than people so even quite small leakage currents into the ground will
cause a large enough voltage gradient to affect them whereas it won't
affect bipeds.

--
Chris Green

A relative has a small outbuilding that needs a general overhaul of
its electrical wiring, and I'm wondering if it could be DIY'd without
coming under Part P.

It's basically a small steel-framed barn that houses a couple of cars
and a couple of horses. There's no wiring in the horses' part. It's
fed by a short buried cable from the consumer unit in the house,
which feeds a smaller consumer unit in the barn. Things which need to
be addressed include: - Most of the sockets and switches are old,
some are cracked. Some may be exposed to rain during severe weather.
- A family of swifts has built a nest on top of the barn's consumer
unit, which needs to be replaced.
- Presumably the earthing requirements need to be looked at,
particularly in view of the amount of earthed steel around.
- I want to fix whatever needs fixing, but this would just be a repair
operation, not a sneaky extension or enhancement.

I have done lesser electrical tasks before, I have a
physics/electronics background, and am prepared to buy specialised
testing kit. If I read up on all the regulations and best practice,
is this legitimately DIYable without falling foul of Part P?



It clearly needs doing in a competent manner by someone fully familiar with
Part P. The cost of getting done professionally will be much less than
buying test gear for a one off job particularly when you add the cost of
certification.. When the building comes up for sale your relative will be
asked if all work has had the proper authorisation.

Peter Crosland

wrote:
The Medway Handyman wrote:
Andrew Gabriel wrote:
This is a very important issue, much more so because of the
horses. Tiny leakage currents which humans can barely feel
are fatal to most livestock including horses, so this has
to be got right.

Really? I didn't know that. What about electric fences for example?

I would have guessed that horses & cattle could have taken larger shocks
than humans because of thier greater mass. How does that work?

I think the major issue is simply that horses and cows are *longer*
than people so even quite small leakage currents into the ground will
cause a large enough voltage gradient to affect them whereas it won't
affect bipeds.

Apparently it's not unusual to find a field of dead cattle, where
lightning has struck the ground and caused a (bovine) fatal pd across
the heart.

In article ,
Peter Crosland wrote:
It clearly needs doing in a competent manner by someone fully familiar
with Part P.

Seems to me it's rather the opposite - it needs a specialist in wiring
where livestock is involved.

The cost of getting done professionally will be much less than buying
test gear for a one off job particularly when you add the cost of
certification..

The economic way would be to get it checked and certificated at the same
time. Test equipment is needed really just to show up any faults - with
decent workmanship and the correct proceeders followed there won't be any.

When the building comes up for sale your relative will be asked if all
work has had the proper authorisation.

So what? It won't cost anymore to have done later - if indeed such a thing
is asked for.

The idea of doing anything *just* with a view to re-sell is one of these
things the TV makeover progs have a lot to answer for...

--
*If we weren't meant to eat animals, why are they made of meat?

Dave Plowman London SW
To e-mail, change noise into sound.