several queries regarding garage electrics

[seriesonewelder]

a few questions so I can be prepared for an electrician to give a quote.
I want to fit a consumer unit in my garage serving the garage/outside lights/sockets only.
The main electric feed cable enters a 'cupboard' at the side of the front door (see pic) and feeds into the house CU in the kitchen the other side of the wall.

From reading other threads I understand I can take a cable from the unit on the far right (cover removed for pic) of the pic (splitting the tails?).
The distance to the new CU is no more than 10m. I want to use armoured cable and route it around the outside of the house, and into the garage which is under the house.

What size cable should I use allowing for a
32amp ring,
2x 16amp sockets,
6amp internal lighting

how do I factor in outside power sockets (x2 doubles) and outdoor lights (alow 6amps?), do they have to be on a seperate circuit/radial?

Thanks

 

[Iain Westland]

big stuff!! ask a sparky, best to be safe

 

[nHill08]

hi

To decide on what cable you need, you firstly need to know the load so im guessing you will be running a compressor and a welder + power ring and lighting.got any current supply or other ratings for those? also trying to terminate SWA in a main junction box neatly and safely would be a bit off a ****** trying to earth the outer steel Armour due to it being designed for singles meter tails. best bet and if it was me i would try and go from your house consumer unit, but that could involve some tricky work with concealing the cablebut im sure someone with a better idea will come along soon

 

[nHill08]

on second thoughts if your getting a sparky to do the work then he should have the skill, science and knowlage of the game

nick

 

[Wozzaaah]

From reading other threads I understand I can take a cable from the unit on the far right (cover removed for pic) of the pic (splitting the tails?).
The distance to the new CU is no more than 10m. I want to use armoured cable and route it around the outside of the house, and into the garage which is under the house.

how do I factor in outside power sockets (x2 doubles) and outdoor lights (alow 6amps?), do they have to be on a seperate circuit/radial?

Thanks

Your best bet is to create a new 'sub main'.
The box with the lid off is called a (5 way double pole) service connector and is commonly referred to as a 'Henley block'. You'd add a new pair of tails to it then run those tails to a main switch/RCD then from there SWA to the garage CU. You shouldn't (and probably aren't allowed to) just run a cable from there straight to a CU as there will be no protection device on it.
I have mine fed from a 100ma time delay rcd so if there's an issue the 30ma garage one will trip first and it's fully protected in the event of any serious fault.

 

[gavuk]

Just had my garage wired up ,tails connected to henley block feeding an enclosure which should house an rcd and mcb ,,this can be combined as an rcbo,,,feeds the swa cable to garage.....rcd is earth faults(protects people) and mcb is overcurrent (protects swa cable).......mine was fitted with rccb which is another name for a rcd and needs a mcb as well to get certificate from sparkey (part P)..Gav

 

[^neo^]

Bigger the better to the CU in the garage, then at least you can add to it in the future.
Can bet your life you won't stick to just a welder! By the time you've added a compressor, pillar drill, lather, mill and god knows what else!

 

[gavuk]

Was reminded that by using a sub main,ie not going through the consumer unit,u potentially run the risk of overloading the rewireable fuse,if the shower and cooker are on in the house and compressors and other toys in the garage ....rewire fuse is rated at 100amp normally

 

[Justme]

rewire fuse is rated at 100amp normally

The one in the pic is 60 amps

 

[seriesonewelder]

QUOTE=nHill08;146822]hi

To decide on what cable you need, you firstly need to know the load so im guessing you will be running a compressor and a welder + power ring and lighting.got any current supply or other ratings for those? [/QUOTE]

the welder is 215amp, I also want to allow for a 3hp+ compressor hence the second 16amp socket

lighting will be 6x 70watt tubes
Thanks

 

[seriesonewelder]

Your best bet is to create a new 'sub main'.
The box with the lid off is called a (5 way double pole) service connector and is commonly referred to as a 'Henley block'. You'd add a new pair of tails to it then run those tails to a main switch/RCD then from there SWA to the garage CU. You shouldn't (and probably aren't allowed to) just run a cable from there straight to a CU as there will be no protection device on it.
I have mine fed from a 100ma time delay rcd so if there's an issue the 30ma garage one will trip first and it's fully protected in the event of any serious fault.

Thats usefull
Thanks

 

[seriesonewelder]

The one in the pic is 60 amps

Presumably this cannot be up-rated...
If not then there is no point in going over 10mm SWA cable.

Cheers