Garage Wiring Advice

[kingeri]

There would be no benefit of running a 16A ring over a 16A radial in your case.

 

[Dan91]

(Its a new built (2015) house and weve just moved in so wanted to put enough in and not have to think about changing anything later on.)


sorry if its been mentioned already but the garage circuit, is it on a 16A mcb in the house consumer unit?

New builds these days seem to just have a 2.5mm t&e go into a whiska box which is then terminated onto a 2.5mm 3 core swa. depending on the garage demand, you might have to upgrade the cable from the consumer unit to the whiska box first.

 

[Lee Mason]

yeah just checked and its on a 16a breaker in the house, and it does appear to be a 2.5mm t&e being fed. not sure about a whiska box as obviously this cable then runs behind the plasterboard.

i thought a 2.5mm was enough for a 16a radial circuit? after seeing the cable i know i cant uprate it to a 32a, which i wasnt intending to do anyway. But are you suggesting the 2.5mm and the 16a wont be enough for a few garage sockets?

 

[Octopus]

^^ it all depends what you plug into said sockets .......

 

[Deleted member 26818]

2.5mm2 T&E can be used with a 20A breaker.
All depends on the installation method.
SWA is rated slightly higher than T&E.
Don’t like the idea of there being two 16A breakers in series, it’s a guessing game as to which would trip in the event of a fault.
As you intend installing extra sockets, and even intend using sockets for lighting, you will need to provide RCD protection.
Easiest method would be to swap the MCBs in the garage for RCBOs.

 

[Lee Mason]

Thanks, so this is what i think im going to get ready.

new 20a breaker in the house cu (maybe an rcbo, my board is full and plan an extension later on, if i replace all breakers for rcbos i can gain 4 slots by removing the dual rcd parts)

new 16a rcbo in the garage (replacing 16a breaker)

new lighting rcbo????? not sure if this is needed.

radial circuit from the garage cu to the plugs.

 

[Lee Mason]

Also i was thinking of wiring the external wall socket into an rcd plug and then into one of the double sockets on the inside. This would reduce the radial circuit by one permanent double, and the external could just be plugged in/turned on when used.

 

[Octopus]

Its best that you get your "mate" involved.....

 

[Deleted member 26818]

If the circuit feeding the garage is already RCD protected in the house by one of the dual slot RCDs, there will be no need for extra RCD protection in the garage.
No need for an RCD plug if the socket you plug into is already RCD protected.

Ideally the circuit feeding the garage should not be RCD protected, though it may have to be as you mention the T&E runs behind plasterboard.