No one seems yet to have commented, at least not explicitly, on the fact that, unless it can be argued to be a "lighting circuit" (and, try as I may ....), use of 1mm² cable is non-compliant with the regulations.
Kind Regards, John
True (although, as you go on to say, 'the regs' don't actually say 'how much' space), but if the cable CSA is too small to be compliant, even an enormous conduit wouldn't bring it into compliance!
As with many things, the regs themselves don't impose any explicit criteria as regards 'overcrowding' of conduit - one has to look to the OSG for 'guidance' about that.
Indeed it's not - but I find it hard to believe that anyone would seriously suggest that a circuit feeing UFH should come into the definition!
I think you're being unnecessarily restrained - I would suggest that it's entirely illogical! Let's face it, if one applied 'everyday definitions', a dedicated circuit supplying, say, just a bell transformer would be thought of as a 'power circuit', yet a circuit supplying 3kW of light fittings would be called a 'lighting circuit'! It makes no sense to me - but, at least for some, 'regs is regs'!
Exactly - which is why we have both agreed that the (attempt at a) distinction is totally daft. In the OP's case, of course, I presume that the UFH feed probably comes from a sockets circuit - so, no matter how one looks at it, it's unlikely to qualify as a a lighting circuit'!
Indeed - it is simply non-compliant with the regulations!
One wouldn't remove them from the outer sheath, but would use (flexible) single cables, and the conduit would definitely have to be earthed (it probably is already). However, it sounds as if there might possibly still be a space problem - i.e. it sounds as if the conduit is really too small!
Indeed - we discussed that here fairly recently. In fact, in the BRB, there is no distinction made in that Table - "lighting and power circuits" is a single entity - with, as you say, a minimum CSA of 1mm² .
Yep, that's why I said that it would then be essential that teh conduit was properly earthed.
Indeed. I'd personally prefer to have an earth single in there as well, if it would fit, rather than rely on the conduit - but others will probably disagree with me!
When you say dedicated spur and dedicated RCBO, do you mean that the RCBO only supplies the UFH? If so, one certainly couldn't call it a lighting circuit! What size/rating is the RCBO?
Probably - aka 'naughty'! However, he might have just been a little 'behind the times'. As you will have seen, prior to the current amendment of regs coming into force (in 2011), 1mm² cable was permitted for 'power' circuits, and that cable size would theoretically be adequate for your UFH, give or take the cramming into conduit!
I predicted right
Sure, provided the conduit and all it's joints are satisfactory and intact (and remain so), then "it is a bit pointless" to also have an earth conductor, and I know many electricians feel that way. I just feel more confident knowing that there is a continuous copper (essentially immune from corrosion!) conductor between the two ends, not dependent on assorted (probably 'concealed') mechanical joints (and survival of the conduit itself) for electrical continuity.If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
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