Swa mcb

[pig89]

Hi what size mcb is best for 6mm 3 core SWA? It will feed a cu in a shed, I suggested not having a cu but they insist on having one to be able to isolate specific circuits. So what size mcb would be best to protect the run up to the cu? The run will be underground.

Thanks.

 

[Taylortwocities]

Surely you will know that from your cable calculations?
This is basic stuff that you will have learnt as part of your domestic installer qualifications.

You are doing this for reward from a client, you cant be up to much if you have to ask on a DIY internet forum

 

[pig89]

I've always thought 32a but people have told me 40a can be used.

 

[ban-all-sheds]

Surely you will know that from your cable calculations?
This is basic stuff that you will have learnt as part of your domestic installer qualifications.

You are doing this for reward from a client, you cant be up to much if you have to ask on a DIY internet forum

Non-rhetorical questions: why don't you know? What makes you think that you should be taking money from people as an electrician?

 

[Taylortwocities]

I've always thought 32a but people have told me 40a can be used.

Well, you know what thought did.

OK, so I am being deliberately unhelpful.
The answer you need is contained in Appendix 4 of BS7671. All you have to do is to look in there.

 

[pig89]

That's what I thought it's just some people make me disbelieve what I already know, thanks anyway.

 

[RF Lighting]

What answer have you decided on then?

 

[flameport]

Hi what size mcb is best for 6mm 3 core SWA?

The best size is the one which is appropriate, considering factors such as cable length, expected loading, voltage and installation method. Other factors may be relevant depending on the circumstances.

I've always thought 32a but people have told me 40a can be used.

There are situations where 32A would be appropriate.
There are others where 40A could be used.

There are yet more where 20A, 25A, 50A, 16A, 10A or many other ratings of MCB would be suitable, and that's before even considering what type of MCB to use.
Then there are those installations where an MCB of any rating would not be appropriate, and a cartridge fuse of suitable type and rating would be used instead.
Although very unlikely, there are situations where no MCB or fuse would be required at all.

 

[ban-all-sheds]

That's what I thought it's just some people make me disbelieve what I already know, thanks anyway.

I've looked at the questions you've been asking here.

Those people must be very lucky to hit on something you know.

 

[phatboy]

Dear Lord, I just read your previous posts.

You are not an electrician, you have less than a quarter of the DIY knowledge I do.

I suggest whoever you are doing this work for, you call them, apologise for lying about what you are capable of, and suggest they call a real electrician, and get everything you have started re-done.

Doing work in your own house is 1 thing, but for someone else you have a lot more responsibilities.

 

[securespark]

Is it XLPE?

 

[JohnW2]

Is it XLPE?

You may need to keep the questions simple

Kind Regards, John

 

[Risteard]

Is it XLPE?

That won't be relevant unless the terminals are suitable for operation at 90 degrees - which I would be pretty confident that they will not be.