Whilst I agree that a brass bolt is the proper way, roofing bolts are designed for roofs and gutters and as such are suitably rated to withstand the elements, admittedly quality has probably slipped but still a perfectly acceptable method, after all trunking and conduit are made of galv steel...
Agree with the above(s), tended to be the cheaper contactors that's only used twin and skin, better domestic installs had CPC's right from the start of pvc, I tested one the other day 1962 and it had cpc, admittedly twisted together above all fittings ;-)
We used to call it pre-wired conduit, I have never installed it but its in lots of council properties from the 70's round our way, as far as reference methods/ccc's are concerned, it counts as singles in conduit I believe.
problem Is for the customer, they will be subject to commercial energy bills if they use a 3 phase supply, not your usual fixed deals etc. or confused.com lol
Don't get one of those trolley things (especially not Stanley) you'll look like a right tool wheeling it across site, and if the ground id rough the wheels will fall off quickly!
well a 4kw 3 phase would only require 1.33kw per phase so a 6A 3 phase supply. A 32 A (per phase) heat pump is BIG, but this is the only reason you would want to supply a domestic gaff with 3 phase surely?
4KW 32A? In first post you said it needed 32A supply?
The other house sounds like a bodge done by a bodging domestic sparks, you need to balance phases.
If you have a three phase supply you really have to balance the phases, (I mean REALLY) So the single phase board and 3 phase switchfuse idea is out. The only way to do this is a 3 phase DB with rcbo's.
You will need to consider how to split the load, how tot make sure the accessories/equipment...
I say that it would be perfectly acceptable to have the RCD at the supply end, however more preferable to have it at the sub-board in the garage, as if it trips you don't have to go back to the house etc. etc.
SWA would not benefit in anyway from RCD protection.
Either way its a garage, if its...
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