Hello All.
I have searched this and several other forums and found lots of advice but nothing that addresses my problem.
I am presently constructing a new house using Insulated Concrete Forms (ICFs). – Just in case you don’t know, these are basically polystyrene Lego bricks with a hollow core which is filled with concrete. The thickness of the polystyrene on the inside is 57mm. This will eventually be covered with plasterboard.
I understand that it is not advisable (or perhaps not permitted) to place pvc cable in contact with polystyrene.
Consequently I have to provide conduit embedded in a chase in the polystyrene insulation for the vertical drops to sockets and switches – max drop length about 2.5m. These will only be from a point above a suspended ceiling where the cables can be surface clipped on timber. The cable runs are fairly long and I don’t want to run long conduits or trunking above the ceiling with singles.
I am weeks away from appointing an electrician but I need to install the conduit drops soon. It has already been decided to do most of the circuits in 4mm² t&e in radial rather than final ring mains.
What I can’t find is clear guidance as to the size of the conduit. I am assuming that the 4mm² t&e would drop down to the socket then rise again to go horizontally to the next drop – this would require two t&es in the conduit.
Or
It could it drop to the first socket then travel horizontally in conduit to the next. This would only require one t&e in the conduit.
Or
Two conduit drops per 13A socket.
Is there another way?
Would it be appropriate to apply the 45% rule as the conduit would be embedded in insulation?
Your advice will be appreciated.
I have searched this and several other forums and found lots of advice but nothing that addresses my problem.
I am presently constructing a new house using Insulated Concrete Forms (ICFs). – Just in case you don’t know, these are basically polystyrene Lego bricks with a hollow core which is filled with concrete. The thickness of the polystyrene on the inside is 57mm. This will eventually be covered with plasterboard.
I understand that it is not advisable (or perhaps not permitted) to place pvc cable in contact with polystyrene.
Consequently I have to provide conduit embedded in a chase in the polystyrene insulation for the vertical drops to sockets and switches – max drop length about 2.5m. These will only be from a point above a suspended ceiling where the cables can be surface clipped on timber. The cable runs are fairly long and I don’t want to run long conduits or trunking above the ceiling with singles.
I am weeks away from appointing an electrician but I need to install the conduit drops soon. It has already been decided to do most of the circuits in 4mm² t&e in radial rather than final ring mains.
What I can’t find is clear guidance as to the size of the conduit. I am assuming that the 4mm² t&e would drop down to the socket then rise again to go horizontally to the next drop – this would require two t&es in the conduit.
Or
It could it drop to the first socket then travel horizontally in conduit to the next. This would only require one t&e in the conduit.
Or
Two conduit drops per 13A socket.
Is there another way?
Would it be appropriate to apply the 45% rule as the conduit would be embedded in insulation?
Your advice will be appreciated.