SWA to workshop - 2 or 3 cores?

Question

HelloI've looked into how to rate the cable I need to supply my workshop andI will get someone in to help with working out the type of earthing thatis best to use. The "run" will be about 50-75' (I'm measuring it laterthis week) and will be to supply power and lighting for single-phaseduty (~ 3kW power plus a couple of strip lights). I'm happy to useonline calculators to estimate correct sizing for permissible % dropunder load. I think 4mm^2 will do it, from memory.What I am unsure about is whether to use 2-core SWA and use thearmouring as the earth, or go for three cores such that one of theose isthe earth.What's best practice?ThanksDDS

Andrew Mawson · Accepted Answer

theose isNo doubt I'll be howled down by the professionals, but for somethingat that distance from the house I've always exported the house earthon the third core (don't like steel conductors!) and also fitted anearth spike. So the third core and the steel wire armour are inparallel and an earth spike at the far end.AWEM

Martin Bonner · Answer

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

ARWadsworth · Answer

an interesting article.However your size or erthing optionss may depend upon any main bonding that may need to be done in the workshop

John Rumm · Answer

OK, the long and detailed answer: answer: for single phase, and where there is no need to export a PME equipotential zone, then 2 core.One of the first things you need to know is your earthing system at the supply end:

SWA to workshop - 2 or 3 cores?

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