Hello

I've looked into how to rate the cable I need to supply my workshop and
I will get someone in to help with working out the type of earthing that
is best to use. The "run" will be about 50-75' (I'm measuring it later
this week) and will be to supply power and lighting for single-phase
duty (~ 3kW power plus a couple of strip lights). I'm happy to use
online calculators to estimate correct sizing for permissible % drop
under load. I think 4mm^2 will do it, from memory.

What I am unsure about is whether to use 2-core SWA and use the
armouring as the earth, or go for three cores such that one of theose is
the earth.

What's best practice?

Thanks


DDS

"DDS" wrote in message
...
Hello

I've looked into how to rate the cable I need to supply my workshop
and
I will get someone in to help with working out the type of earthing
that
is best to use. The "run" will be about 50-75' (I'm measuring it
later
this week) and will be to supply power and lighting for single-phase
duty (~ 3kW power plus a couple of strip lights). I'm happy to use
online calculators to estimate correct sizing for permissible % drop
under load. I think 4mm^2 will do it, from memory.

What I am unsure about is whether to use 2-core SWA and use the
armouring as the earth, or go for three cores such that one of
theose is
the earth.

What's best practice?

Thanks


DDS

No doubt I'll be howled down by the professionals, but for something
at that distance from the house I've always exported the house earth
on the third core (don't like steel conductors!) and also fitted an
earth spike. So the third core and the steel wire armour are in
parallel and an earth spike at the far end.

AWEM

On Mar 21, 11:42*pm, DDS wrote:
Hello

I've looked into how to rate the cable I need to supply my workshop and
I will get someone in to help with working out the type of earthing that
is best to use. The "run" will be about 50-75' (I'm measuring it later
this week) and will be to supply power and lighting for single-phase
duty (~ 3kW power plus a couple of strip lights). I'm happy to use
online calculators to estimate correct sizing for permissible % drop
under load. I think 4mm^2 will do it, from memory.

What I am unsure about is whether to use 2-core SWA and use the
armouring as the earth, or go for three cores such that one of theose is
the earth.

What's best practice?

I have a feeling that the answer may depend on the type of earthing
you are using.

DDS wrote:
Hello

I've looked into how to rate the cable I need to supply my workshop
and I will get someone in to help with working out the type of
earthing that is best to use. The "run" will be about 50-75' (I'm
measuring it later this week) and will be to supply power and
lighting for single-phase duty (~ 3kW power plus a couple of strip
lights). I'm happy to use online calculators to estimate correct
sizing for permissible % drop under load. I think 4mm^2 will do it,
from memory.

What I am unsure about is whether to use 2-core SWA and use the
armouring as the earth, or go for three cores such that one of theose
is the earth.

What's best practice?


http://www.gadsolutions.biz/regulations/swa-as-the-cpc

has an interesting article.

However your size or erthing optionss may depend upon any main bonding that
may need to be done in the workshop
--
Adam