Need some consumer unit advice please

[squeezyphil]

Hello,

So I am having my newly built workshop wired up soon. I had the electrician around yesterday to talk through the job. I will be running a 10mm twin core SWA armoured cable underground to the workshop. It will run off the house consumer unit and have its own consumer unit in the workshop. I will be running a fairly big lathe and some other machinery, hence the size of the cable.

When the electrician was around yesterday, he mentioned that it could run off an unused 50amp mcb in the house consumer unit. Thats fine, but I'm wondering what consumer unit to get for the garage as I see that the main breaker switches for consumer units generally come in 63 or 100 amp sizes. Is it alright to run the power from a 50 amp mcb in the house consumer unit to a consumer unit in the workshop that has a main trip switch of 63 amps? Or should I get a bigger 63 amp mcb for the home consumer unit? Or am I getting this totally wrong? Any help would be greatly appreciated.

I'm only asking now as I am hoping to get most of the bits bought asap and he is away at the moment and am not able to contact him. I will be calling him as soon as he is back but for now was wondering if anyone online could help.

Thanks,

Phil

 

[Andy78]

You should OK your choices with the electrician that is installing and certificating the job. If they don't agree with your choices you won't save time but waste it.

 

[Cadgey123]

Hello,

So I am having my newly built workshop wired up soon. I had the electrician around yesterday to talk through the job. I will be running a 10mm twin core SWA armoured cable underground to the workshop. It will run off the house consumer unit and have its own consumer unit in the workshop. I will be running a fairly big lathe and some other machinery, hence the size of the cable.

When the electrician was around yesterday, he mentioned that it could run off an unused 50amp mcb in the house consumer unit. Thats fine, but I'm wondering what consumer unit to get for the garage as I see that the main breaker switches for consumer units generally come in 63 or 100 amp sizes. Is it alright to run the power from a 50 amp mcb in the house consumer unit to a consumer unit in the workshop that has a main trip switch of 63 amps? Or should I get a bigger 63 amp mcb for the home consumer unit? Or am I getting this totally wrong? Any help would be greatly appreciated.

I'm only asking now as I am hoping to get most of the bits bought asap and he is away at the moment and am not able to contact him. I will be calling him as soon as he is back but for now was wondering if anyone online could help.

Thanks,

Phil

Get your electrician to get the garage unit.
Just tell him your specification and he can pick up the right items.

When customers try to buy themselves materials, always leads problems IMHO.

 

[Deleted member 26818]

Main switches don’t trip.
The amp rating is the maximum current they are designed to carry under normal working conditions.

 

[Spoon]

As above. Leave the buying of the bits to the electrician.
No offence to you, but you will just buy the cheapest cr*p you can find. "Save money..", then if the parts go faulty in 11 months you will go whinging to your electrician.

 

[squeezyphil]

thanks for the obvious helps guys, i will be contacting my electrician to confirm parts, just maybe some help on what size house mcb and main switche for workshop would be some help and as for ""No offence to you, but you will just buy the cheapest cr*p you can find."" haha you have not seen this worklshop build, its far from the cheapest crap!.. i dont buy cheap crap, i but quality crap that lasts

 

[Spoon]

...and as for ""No offence to you, but you will just buy the cheapest cr*p you can find."" haha you have not seen this worklshop build, its far from the cheapest crap!.. i dont buy cheap crap, i but quality crap that lasts

It's just what most people will do.. It seems it's all about the money. Glad that's not the case with you mate.

 

[Spoon]

thanks for the obvious helps guys, i will be contacting my electrician to confirm parts, just maybe some help on what size house mcb and main switche for workshop would be some help...

The house MCB will all depend on what load the equipment will use. Your electrician should be able to calculate this. Or you can, if you know all the equipment that is being fitted.

But as your electrician has stated that a 50A mcb will be fine then I would go with that.

 

[squeezyphil]

thanks, and yeah as my electrician said, i also believe 50 amp breaker in the house will be fine. The bit i dont understand is the other end of the armoured cable at the consumer unint in the workshop. What amp size main switch should I have? I can only seem to find 63 amp or 100 amp main switch consumer units. Would it be alright to run a 63 amp main switch in the consumer unit in the workshop with the house mcb being 50 amp?

 

[Spoon]

thanks, and yeah as my electrician said, i also believe 50 amp breaker in the house will be fine. The bit i dont understand is the other end of the armoured cable at the consumer unint in the workshop. What amp size main switch should I have? I can only seem to find 63 amp or 100 amp main switch consumer units. Would it be alright to run a 63 amp main switch in the consumer unit in the workshop with the house mcb being 50 amp?

Please read post #4 by @spinlondon .
It's used to isolate the supplies going out of the garage cu..

 

[Octopus]

Who decided that 2 core swa was the right solution?

 

[squeezyphil]

ok thanks spoon, and spinlondon. that has cleared it up, I did not realise that mainswitches now dont have overcurrent protection etc.. and are just an isolation switch. makes sense, thank you

 

[kingeri]

If I had gone to a job and seen a customer then found out they were going online to find out what materials to buy I wouldn't be particularly impressed. Why not just wait and let the electrician get everything, that way you know it will all be right, and also more likely to be guaranteed by him. There is an electrician involved...right??

 

[Cadgey123]

If I had gone to a job and seen a customer then found out they were going online to find out what materials to buy I wouldn't be particularly impressed. Why not just wait and let the electrician get everything, that way you know it will all be right, and also more likely to be guaranteed by him. There is an electrician involved...right??

Sounds like he is going behind his electricians back and either trying to outsmart or outprice him. That’s if he even has one. Knowledge is key but I reckon he is asking too many questions.......

 

[Deleted member 26818]

Considering the amount of incorrect advice I’ve received over the years from so called experts, I can not fault anyone researching something like this thoroughly.