On Wed, 11 Jan 2006 21:48:59 +0000, SR wrote:

My latest cock-up: Having dug 15M trench, put SWA cable in and
re-filled, I've now discovered it's a 3 core rather than 2 core cable.
Doh! (It did seem a little thick, but I hadn't used any SWA for a
while...) I could just go ahead and use it anyway I suppose, but since
the core colours are brown, black and grey as for 3-phase system, I
can't use the correct single phase colour scheme - there's no blue.

Is there a way round this without digging the whole bloody thing up again?

SR

Don't worry - that's normal. I've not seen any 2 core myself, most if the
sheds sell 3 core anyway.

The consensus of opinion on the IEE forums suggest this (old and new 3
phase SWA colours used in single phase installations) (with some
differences of opinion):

RED OR BROWN - LIVE
YELLOW OR BLACK - EARTH (SLEEVED GREEN/YELLOW)
BLUE OR GREY - NEUTRAL (SLEEVED BLUE)

The whole thread is here, so best check it out yourself:

http://www.iee.org/Forums/forum/mess...&threadid=4722

The important bit is that you sleeve the conductors at each termination
correctly to indicate their true meaning, eg brown sleeve=live,
blue=neutral, yellow/green=CPC earth

I'm not an expert though I have laid SWA before. Although in many cases
the armour should make a sufficiently good earth connection, you should in
theory prove it. The easy way around is to, as is commonly done, use one
of the cores as an earth as shown above. But you must also connect the
armour to this earth CPC via the solder ring that comes as part of the
gland kit. I suspect you knew that, sorry, just being careful.

This assumes that you are exporting the supply end earth to the
destination, rather than using a local rod.

HTH

Tim