On 17 Dec 2004 14:59:49 -0800,
(jim_in_sussex) strung together this:

1. Is it correct to use
IEE table 4D1A/ref method 1? (the illustrations for method 1 don't
refer specifically to underground use).

I don't have any regs to hand, I'm sure someone else will.

2. Ducting: Instead of burying it in bare soil it looks more sensible
to run it inside a duct,

Why? Unless you're likely to be pulling it out then bury it direct.
There's no mechanical advantage to be gained from running SWA in a
duct.
The current rating will be the same.

3. Termination: how do you connect
the garage end into a standard plastic consumer unit?

Two ways, first is to terminate directly into the PVC enclosure and
the second is to terminate into an external PVC or metallic enclosure
then run from this to the CU with T&E or something similar.

4. Earthing: I'm not completely happy about relying on a non-copper
earth (ie the steel armour).

I always use 3 core SWA and use the 3rd core as an earth. Common
practice really.
Earthing, I'm not going to get into this one.

5. Cable size: nominally 6mmsq cable is adequate for the garage load
(ring + freezer radial + lights), but am wondering about using a
larger cable - eg 16mmsq. There'd be 2 benefits - much lower volt
drop, plus less light flicker when a machine starts. Relative to the
whole project the extra cost is small, but are there any practical
snags? Does anyone know the outside diameter of these cables?

6mm about 20mm OD, 16mm about 30mm OD. You can use either, I'd go for
anything from 6mm upwards for a 32A supply over the distance you've
got.

6. Finally looking up the ratings for these cables in the IEE regs &
comparing with the TLC catalog, why the differences?

Email TLC and ask, could be a number of reasons.
--

SJW
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