Hi there, just moved into new property and my predecessor has installed a spur off the radial circuit in what appears to be 1.5mm T&E, as I only intend to ever run the tv and sky box of this socket can I leave it as is or do I have to rip it out and replace with 2.5mm or even 4mm?
Spur in 1.5
- Thread starter Chiwillie
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What amperage is the fuse or breaker that protects the circuit ?
If it's supplying just one single socket, that should be fine, even if it is a 32A circuit, and despite it not being one of the examples given in the Wiring regs.
Kind Regards, John
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OK, that presumably means that it is a 4mm² radial?
As I said, if the spur is only supplying one single socket, then 1.5mm² cable is fine (regardless of the rating of the MCB), since it has downstream protection of (at worst) 13A in the plug fuse. Is it a single or double socket?
Kind Regards, John
32amp MCB
A double socket and yes its in 4mm T&E
The double socket makes it a little more complicated. Assuming the 1.5mm cable is installed by 'Method C' (clipped to a wall, buriied in plaster, loose inside a wall etc.) it has a current-carrying capacity of 20A - so, if there is a possibility that the downstream protection might be as high as 26A (13A fuses in each of two plugs), then 1.5mm² cable would not be adequate and you would, strictly speaking, need 2.5mm² cable.
In reality, given the loads you describe, there is no problem at all. However, if you wanted to be strictly within regulations, then there would be a number of options:
1...Change the double socket to a single one (and keep the 1.5mm² cable)
2...Install an FCU, with a 13A fuse, in the feed to the double socket (and keep the 1.5mm² cable)
3...Keep the double socket and change the cable to 2.5mm².
If you wanted more than one double socket to be fed by the spur, you would probably need 4mm² cable (at least for the feed to the first socket), but I don't think there is any question of your wanting that.
Kind Regards, John
Thanks for all of that John,
point 1 does anyone make a single socket to fit a double back box?
Point 2 not sure where I could easily fit an FCU
point3 looks like I will have to rip it out and start again, not sure whether it's in conduit or something else as it runs horizontally.
Won't be having any more sockets fitted so no 4mm² required
point 1 does anyone make a single socket to fit a double back box?
Point 2 not sure where I could easily fit an FCU
point3 looks like I will have to rip it out and start again, not sure whether it's in conduit or something else as it runs horizontally.
Won't be having any more sockets fitted so no 4mm² required
Not 'literally' that I am aware of (but others might prove me wrong). However, you could do it with a 'modular' system, which would allow two socket modules to be installed on one (double size) front plate - but using a blanking plate (assuming available) instead of one of the socket modules
Fair enough. Since I don't have a flak jacket to hand, I have to be careful what I say but, as I said, for the loads you have in mind, there really is no problem with the 1.5mm² cable, so I know what I would do (or not do) if I were in your position
Thinking a little laterally, one other thought ... you could get one of the (much criticised and 'deprecated') 'socket protectors' (a plastic thingy with three prongs which plugs into a socket) and supeglue it into one of the sockets, thereby effectively turning it into a single socket!
Kind regards, John
A double socket-outlet is only rated for 20A - not 26A.
That does not stop two 13A appliances drawing 26A.
No, it doesn't. But then the cable size isn't the only problem. The burnt out or on fire socket-outlet will be an issue anyway.
As has been said, that's irrelevant. We are talking about the downstream overload protection of a cable feeding a double socket, and that could be provided by two plugs each with 13A fuses (hence 26A total), regardless of the rating' of the socket and/or the current drawn by the loads.
It's the only issue ('problem') being discussed in this thread.
Your views about the loading of a double socket should be in a different thread, if anywhere.
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