New Workshop Electrics

[barracuda816]

What's feeding the garage at the moment. I agree with tapping the 25AWG coming into the garage and feeding a Consumer unit in the new workshop. Work out your circuits and buy a consumer unit with a few extra spaces. Also look into proper grounding, It will depend on distance from the house (length of run) and a number of other factors like the grounding you have coming in at the house and what you end up using for breakers (RCBOs etc) I would recommend you have a look through the 18th edition if you can find a online of free copy. It has a ton of good info (even if a lot is hotly debated) and if you do it to the 18th edition standards you can't really go wrong. It's pretty easy to understand the majority of it.

 

[Dave-sparks]

I don't know the regs... sure someone else will be along soon who does... but if you put it in a duct you don;t need to use armoured cable, which means you could get something much easier to run

Generally you will still need to use armoured cable, being in a bit of plastic tube doesn't offer the same protection as an armoured cable.

If you use a specific type of duct and install it in accordance with manufacturers instructions etc etc then you can use an alternative type of cable, but it is not the case that any duct will do.

 

[brightspark]

just use armoured and bury it in sand then overfill its hardly likely u will need it renewing so pointless putting it in ducting . mines under the drive across to garage for the last 40 years without problem . its 35mm only because i got it for nothing otherwise it would have been 10.0mm and that well covers everything

 

[aesmith]

None of this new route will be underground. It's all going to be above head height, clipped to wall or purlin. Then there's approx 1.3m gap between builders, I was planning on crossing that in steel pipe. Then it will need to come down a couple of meters to enter the new shed just below the eaves. This plan likely won't be finalised until the shed's in place.

 

[aesmith]

What's feeding the garage at the moment. I agree with tapping the 25AWG coming into the garage and feeding a Consumer unit in the new workshop.

This is the board in the garage. Tapping into the 25sq.mm doesn’t look trivial, I'm pretty sure it can't just be joined at the main switch unless the incoming terminals can really take two lots of 25mm (safely).

Assuming the can't I guess I would need an external enclosure splitting it three ways before the garage board.

 

[Dave-sparks]

None of this new route will be underground. It's all going to be above head height, clipped to wall or purlin. Then there's approx 1.3m gap between builders, I was planning on crossing that in steel pipe. Then it will need to come down a couple of meters to enter the new shed just below the eaves. This plan likely won't be finalised until the shed's in place.

in which case the above suggestion of an alternative cable type is sensible, if it's not buried and not likely to suffer mechanical damage then armoured probably isn't necessary.

Flexible H07-RNF type cable would be ok but still very heavy, or else you could look at NYY-J as an option.

 

[Dave-sparks]

This is the board in the garage. Tapping into the 25sq.mm doesn’t look trivial, I'm pretty sure it can't just be joined at the main switch unless the incoming terminals can really take two lots of 25mm (safely).

Assuming the can't I guess I would need an external enclosure splitting it three ways before the garage board.

No you wont get be able to sensibly connect 2x25mm together inside that CU.

Personally I would either install re-terminate the existing cable into an enclosure below the CU and make the joint using DIN rail connectors (either the bolted type or WAGO screwless for preference) or else use a breach joint on the existing armoured.

 

[Dave-sparks]

So I'm looking at 10 or maybe 16mm2. But I'd like to verify voltage drop taking into account the 45m to the garage as well as the proposed garage to shed.

Youre doing this a bit backwards, you need to start from the current required and work out a cable size from that, not pick a cable size and work backwards from there.

 

[aesmith]

Youre doing this a bit backwards, you need to start from the current required and work out a cable size from that, .

I'm floundering a bit to be honest in terms of working out demand. But I'm certain that 9kW would be a generous upper estimate. Just sizing from that suggests what seems a ridiculously small cable, for example clipped direct appears to only need 4mm.