adding sockets to an external garage building...

[amr9429]

Hi,

I have a flat with a garage. The garage is in a seperate block to the flats. Each garage has a power supply into it which consists of:

1 X metal clad spur with 5A fuse. Thats it!

This powers an electric garage opener. I'm told by the garage owners to add power sockets if i like for low power items (eg trickle charger). If I plan to use high power tools I would trip power for a number of garages..

However, None of this is RCD'd. I was wanting to add a CU (with RCD), which will feed off it one socket and a spur for garage opener.

Issue is the RCD is 63A rated. Can I attach the RCD so long as I keep the metal clad 5A fuse before it? (effectively limiting CU to 5A). I dont mind being limited to 5A as all I would use is a trickle charger or small lamp.

Many Thanks..

 

[londonboy]

You could just fit an SRCD (RCD Socket) on the load side of that spur with the 5amp fuse.

This will obviously limit your socket to 5amps, which is sufficient for chargers etc.

 

[ban-all-sheds]

And if you wish to stay legal, installing an RCD socket will be much cheaper than installing a CU.

 

[amr9429]

i dont mind so much about the cost of the CU over a SRCD. I would just like to have items on seperate breakers A couple of flourescent tubes on one, the sockets on another.

@ban-all-sheds...
are you saying putting a CU in there would be illegal??

 

[1john]

You are limited to 5A so why bother with the CU, you wont find any breakers less than 5A to fit in it, IIRC MK do a 3A breaker but I doubt anyone will have one on the shelf anywhere. Best thing to do here is as stated already, spur off of the load side of the FCU with an RCD socket.

 

[amr9429]

fair enough. i see your point..

Can I then wire other (non RCD) metal clad spur sockets off one SRCD? and is that legal?

 

[OwainDIYer]

RCD sockets don't have 'output' terminals to run other protected sockets from.

If you are concerned about lights going out, a battery back up emergency lighting unit doesn't cost much.

 

[Stoday]

You can run lights off the load side of the FCU without a RCD because your cables won't be hidden in plaster. If you want more sockets, add RCD sockets.

In principle, you are supposed to notify Building Control if you fit a CU. They'll charge you £200 — £500 to get someone to test it and tell them it's OK, if you do. A CU is a bad idea technically and financially.

 

[ban-all-sheds]

i dont mind so much about the cost of the CU over a SRCD. I would just like to have items on seperate breakers A couple of flourescent tubes on one, the sockets on another.

It's not the cost of the items that is relevant - if you want to do it legally it's the cost of notifying that matters.

I would never advise compromising good design to avoid notification, but adding a switch for the light and an RCD socket is not a really poor idea.

are you saying putting a CU in there would be illegal??

You should read this.

 

[amr9429]

View media item 31661
Guys, thanks for all the help. I've drawn an image to make life easier.

This is what I could do from what I've understood so far. Let me know what you think if there are issues with it.

The sockets would be used for a trickle charger or small lamp. The garage hasnt got lighting at present so the 16W flourescent tube would be on my wish list.

I've tried to design it to have as little spurs as possible and keep it a ring for best practice (where possible).

Thanks.

 

[echoes]

I can't see anything wrong with that. Might be a bit tight for cable space behind your 5A FCU.

What you've drawn is not a ring, but a radial fused at 5A, and as such there is absolutely no problem adding 'spurs' and branches to it.

Your garage door dedicated socket (non-RCD) should be marked as such, as the presence of the presence of the label generates a force-field which physically prevents anyone from plugging in anything likely to be used outside.