Garage electrics

[Ben1127]

Hi all, I'm thinking of using this cable to supply power to my garage which is about 10 meters away from the house, I will be fitting 9 double 13amp sockets, 4 6' fluorescent lights and will be using the usual garage equipment angle grinder/ mig welder/ power tools etc, will this cable be ok

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[ericmark]

Mig welder likely need 80A at least at 25v + 1 volt per 25 amp around 28 volt output so will need around the full 13A when used. Assume lights used at same time so would guess will need 16A supply and cable rated around 20A so that's OK. At 10 meters likely you will use house earth again likely no problem.

These assumptions could be wrong so can't say yes OK but likely with a B16 RCBO there will be no problem. Will need glands and some box to terminate into both ends etc. etc and also likely this will be new circuit so will come under part P building regulations and it not a TN supply may be better with it's own earth rod the list goes on but so far so good.

 

[Ben1127]

Thanks, was thinking of using a MK Sentry IP65 6 way c/w 63 amp rcd + 6mcb 2 x 20amp 1 x 16amp 3 x 6amp

 

[securespark]

Cable seems very thin for that many breakers.

 

[ericmark]

The cable is just on the limits to use B32 MCB table 4E4A would seem to cover for clipped direct ref method 1 other installation methods could mean it is under the 32A you intend to use. See http://www.batt.co.uk/products/view/383/BS5467-SWA/PVC-Cable-IEC-60502-600/1000V for details on cable.

 

[RF Lighting]

That's for XLPE cable running at 90°C.

The OP needs a bigger cable.

 

[knowall]

6mm 3 core swa. Here we go !

KA

 

[SimonH2]

Thanks, was thinking of using a MK Sentry IP65 6 way c/w 63 amp rcd + 6mcb 2 x 20amp 1 x 16amp 3 x 6amp

Waste of time if you use that cable. I think you'd need to use a 20A* MCB at the supply end, so there's no point using any larger or equal sized breaker at the load end. So you might as well just use a standalone RCD (you can get a 2 module housing that will allow you to have just an RCD in a housing), and supply the lights from an FCU (which could double as the switch if you locate it sensibly. All the sockets and the FCU would just be a radial, ie supply->RCD->socket->socket->socket->…

Most of your power tools will be OK, but …
The MIG welder could be an issue - may trip the house end MCB at inconvenient times. Also, if you have large tools (like high powered bench saws), you may find it drops the supply voltage enough to make the lights flicker at startup.
On that, I strongly suspect that the circuit wouldn't be compliant on volt drop. Ie the voltage at the garage may drop more than the regs allow for.

My suggestion, given the nature of the tools you're talking about using, would be to consider a larger cable and a 'proper' supply. IMO, an ideal would be a cable sized to allow a 40A MCB at the supply end, so you can use a 32A MCB for the garage sockets and have some discrimination. Better still is probably to use a cartridge fuse at the supply end, as there isn't actually much discrimination (for faults rather than just overloads) between series linked MCBs - even of different ratings.
having said that, I can't remember the last time I tripped a B32 with a MIG welder - even when welding 4mm plate on a Land Rover chassis with an industrial size machine.

* I believe that would be OK for this cable, others will know better than I do.