Breaker sizing

[matt12321]

What size breaker do I need at my db in the house, which feeds an outside building on 6mm armoured. The outside building has a db with 40, 32 and 6 amp breakers for cooker, ring and lights.

 

[malcolmsanford]

Matt what is the meaning of life???

Give us something to work on, cable size, what kind of cable, how will the cable be installed, distance of cable run, earthing system, is there any services in this outside building, Does the sub main need RCD protection, where is the RCD going for the outside building.

 

[Electro-tech]

More info needed on loads of appliances etc and most of all length of cable run between buildings.

Beat me to it Malcolm.

 

[Sintra]

You could find that the 6mm is undersized even to run the cooker never mind anything else depending on length of run etc.

 

[matt12321]

6mm armoured. 3 core. Tncs. No services. 30 meter run underground. Rcd protected in the outside building and at house

 

[malcolmsanford]

So with RCD protection at both places you already will have a discrimination problem.

What KW is the oven, as you will need that to work out your diversity on the circuit, if you haven't got the oven size then and your going with that 40amp MCB for it, then I can tell you now that 6mm is not going to be anywhere big enough.

That 6mm at the best is only going to be rated at 46 amps, before volt drop is worked out.

 

[matt12321]

What if is electric oven gas hobs.

 

[matt12321]

Now worrys cooker is on plug top plus it want be drawing maximum

 

[malcolmsanford]

So now your design will go from what 32amp ring final 6 amp lights 16amp radial for oven??

No services? is this going to be calor/LPG gas then. No water facilities for cooking???

 

[telectrix]

16A cooker, 16A sockets (ring or radial) , 6A lights. 40A on the 6mm (providing ccc and VD are within limits). feed from non-RCD protected MCB.

 

[matt12321]

I'll start again. 32 amp main breaker in the house not rcd protected. 6mm 3 core armoured buried to out building. Db in outbuilding with rcd for lights 6a, ring 32, cooker 40a. Mains water PVC in to building. Tncs

 

[ezzzekiel]

ok 6a - wheres my prize