Loft Insulation & Electrics

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I wish to add another layer of loft insulation across the joist in my loft as recommended. I have cables attached to the joist and would be covering these. Is it ok to do so?
 
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you need an electrician to be sure (probably post needs moving).

before i new anything about electrics i did the same and have had no trouble in over 10 yrs.

i now know a bit more and if i am rewiring in a loft i go up a size in cable just to be sure if i'm covering with insulation ie 1.0mm to 1.5 for lighting.

i would follow the cable routing and see what they are supplying - if it’s just lights (and no big wattage) then i am sure you will be ok.

if it's a power circuit or heavy usage then I’d think about moving the cable higher out of the insulation (if poss) or renewing the section in the insulation. i believe shrouding is not a good idea either.
 
lighting circuits are very lightly loaded so can be covered (assuming a normal 6A domestic lighting circuit and no huge chandeliers or floodlights).

Electric shower cables are quite near their limit so can't be

Immersion heater cables would need a calculation to be sure but best not.

The good news is that if they are in contact with a ceiling (so they can lose heat into the room below) that is enough, but protect them with builders paper or something to prevent the insulation settling and surrounding them.

the bad news is that if you have to double the capacity of a shower cable, the new one will be ££££s per metre. Best to reroute them round the edges and above the insulation instead. You can put a single cable (not a bunch of them) into conduit or mini-trunking, no prob, without derating.

Tell us what circuits you have, whether it is rewirable fuses or MCBs, and what the amp ratings are, how long the cables are, and we can advise further.
 
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TTC, nice & interesting doc. pleased it's going into the on site guide.

bottom corner of joist is best position - quite a surprise as you would naturally think the higher up the joist the better (ie the nearer to the cold)
 
Close to ceiling is better as the room below will be cooler.

Mind you, if you clip the cables 50mm up the joist (like you should) then you are in the hotter zone :cry:
 
even better still would be ontop of any insulation, maby still some 4 x1 down to clip the cables on.
 

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