Cables, insulation and separation

[bernardgreen]

I like the gutter idea. The only thing I would consider is to leave the cables on the plaster board ceiling and place the guttering over them before laying the insulation on top, I wouldn't trim the thickness to fit the gutter, just let in compress at that point. With the drain pipe ends to allow some air circulation I feel that would be safe. I notice there is a rating for cable with one side in contact with plaster yet apparently no data about the other side of that cable other than it must not be in contact with insulation. I caould find not specification about how much free space there must be around the side of the cable not in contact with the plaster. So maybe just a 2 inch deep free space above the cable laid on the plaster board ceiling is compliant for the cable to be part of a ring final fused at 32 amps.

 

[DJM]

Deleted - DJM only wants agreement to his hare brained idea.

Untrue

It was a hare brained idea, it was explained to you why it was hare brained, and you do not want to accept the status quo

Untrue

The one who doesn't get it is you, you came here for free advice, you've been given excellent free advice, and now you get stroppy because its not what you wanted to hear.

Untrue

I gave you reasons but you did'nt like them

Untrue

While you're there could you ask them [The IET] to explain why it is safe to install cables in the corners of rooms, because its an answer that escapes many highly intelligent people and five year olds

Interesting statement since it is the IET regulations you were stating were the bible and must be obeyed.

Meanwhile go swivel.

I'll leave the moderators to deal with that sort of unnecessary abuse.

Aside from that thank you for your advice

 

[DJM]

I like the gutter idea. The only thing I would consider is to leave the cables on the plaster board ceiling and place the guttering over them before laying the insulation on top, I wouldn't trim the thickness to fit the gutter, just let in compress at that point. With the drain pipe ends to allow some air circulation I feel that would be safe. I notice there is a rating for cable with one side in contact with plaster yet apparently no data about the other side of that cable other than it must not be in contact with insulation. I caould find not specification about how much free space there must be around the side of the cable not in contact with the plaster. So maybe just a 2 inch deep free space above the cable laid on the plaster board ceiling is compliant for the cable to be part of a ring final fused at 32 amps.

This was pretty much what I had found which is why I wondered if the idea might fly. I did consider using the gutter as a tunnel, but rethought it because heat rises and having an open top seemed to offer a better heat dissapation route.
But as I always said, unless I can confirm it's compliant in some way I'll leave it as is and have to kill the planet a bit more by putting the heating up in the room to compensate for the lack of floor insulation

 

[JohnW2]

This was pretty much what I had found which is why I wondered if the idea might fly. I did consider using the gutter as a tunnel, but rethought it because heat rises and having an open top seemed to offer a better heat dissapation route.
But as I always said, unless I can confirm it's compliant in some way I'll leave it as is and have to kill the planet a bit more by putting the heating up in the room to compensate for the lack of floor insulation

I also quite like the guttering idea, and I personally would have thought it was compliant with the regs (as being 'in a ceiling void', without insulation) - the only possible quibble being the degree of thermal contact between the cable and the plaster. However, it's probably no worse than the common situation of cable just lying on plastboard - which, if the cable has a few bends and kinks often means that the cable is only touching the plasterboard 'every now and again. If the cable is not in contact with insulation and has 'free air' above it (as much as it would have were there no insulation in the equation), I can't imagine that it wouldn't be compliant - but that, obviously, is just my personal opinion. I would be less keen on Bernard's suggestion, since the cable is then to some extent in an 'insulated space'; as is being discussed, that might still be compliant, but your approach would seem to be more certain.

Kind Regards, John.