CU or Isolator switch in garage?
- Thread starter frediaz
- Start date
Sponsored Links
Yes, I think we all know that.
Maybe - that is the question we're discussing ...
Yes, I've been thinking a bit more about this. What I'd overlooked was that the fault current in a domestic installation may well be below 640A (maybe well below), it's quite possible that a D32 would never trip magnetically. That could produce issues in relation to disconnection times and would, I imagine, require a pretty hefty cable.
Kind Regards, John
Sure, but that's totally different, and precisely what Type Cs and Ds were designed for - to have much higher magnetic trip thresholds (not to act slower with the same current).
Maybe - but that's what we're discussing, or speculating about - and I fear that we are short on hard facts!
Kind Regards, John
Sure, that's the 'proper'/formal way to do it - but it is also the option which many/most people who discuss garage supplies here are seeking to avoid.
Kind Regards, John
Sponsored Links
If you mean to run the cable (from the CU MCB) straight to the garage socket, with an FCU from there for the lighting, then I think that is very probably the most sensible solution for you. The 'secondary discussion' is really, IMO, essentially academic.
Kind Regards, John
I was thinking of taking the cable from the CU into the FCU first and then from there two branches: one for the socket amd one for the lights. Can I put the two cable sizes (1.5 and 2.5mm) together in the same FCU? Or why would it better to go to the socket first?
Why remove it?
Yes, it matters, as you are replacing the cable and become responsible for the clearance, or lack of, below it. The guidance is 3m.
Because the FCU would then limit all your sockets to a total of 13A.
Running it directly to the first socket would allow you to draw upto the rating of the breaker in the house CU from the sockets, and the FCU then provides the suitable protection for the lighting.
Running it directly to the first socket would allow you to draw upto the rating of the breaker in the house CU from the sockets, and the FCU then provides the suitable protection for the lighting.
Doesn't seem to me as if there is an electrician deciding things.
You don't seem to have a clue what the FCU is for.
So why don't you tell me wise one
I see what you mean but:
There is only one double socket, as I said on the first message, so, for instance if I connect:
socket 1- Lawnmower at 1300W 5.7A
socket 2- Machine in garage 1300W 5.7A
light: 100W 0.4A
Total design current: 11.8 A
I guess if I started adding plug adaptors and connecting more things I would go above the 13A on the design current
whats the rating of the MCB in the house?
If you put the sockets on an FCU, you'd need a second FCU for the lights, as they need to be protected by a lower fuse rating than the sockets.
If you put the sockets on an FCU, you'd need a second FCU for the lights, as they need to be protected by a lower fuse rating than the sockets.
Like I said, the CU has not been installed, so the sparky will recommend the MCB rating. I guess the socket could be regarded as an external socket, connected directly to the MCB (say 16 A) and then take the spur from the socket for the lights with the FCU in it.
I just thought it would be nicer to have one switch that would disconnect everything in the garage but that could be done at the CU.
Or install an isolator switch (no fuse?) for all af them, instead of the FCU but I do not know about this.
If you want an isolator for the garage, run the cable into a 20A DP switch, then on to your socket and FCU for the light.
Should be fine so long as the MCB at the house is 20A or less.
Should be fine so long as the MCB at the house is 20A or less.
DIYnot Local
Staff member
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.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
