Consumer unit capacity help required

[tireetim]

Hi, Can anyone please help me check on what would be required for a new 45A circuit to feed a pottery Kiln. I will get an electrician to do this work but want to double check on here (before buying the kiln) to make sure it is done safely and correctly. Thanks.
Currently my house has a 60Amp main fuse and has just been completely rewired from this point on with a new consumer unit configured as follows :
80A RCD
32A MCB (Cooker)
20A MCB (sockets)
20A MCB (Sockets)
6A MCB (Lights)

80A RCD
32A MCB (Kitchen Sockets, ring)
20A MCB (Sockets)
6A MCB (Lights)
6A MCB (Lights)

There are quite a few spare slots on the consumer unit as I requested this for expansion when the rewire was done.
My guess would be that a new 45A circuit should be fitted with it's own RCD as adding it in to one of the existing ones would over load it (or can one of these be increased accordingly)? Also, would the main 60Amp fuse to the properly be too low? I thought these were normally 100Amp but could be wrong.
Many thanks for any help.

 

[ban-all-sheds]

Before going any further with the project, have you obtained permission from your DNO for the kiln?

Spoiler

Yes, you do.

 

[tireetim]

No, didn't think it would be necessary. It's a private house and a hobby kiln. Would you need such permission for a range cooker or similar household appliance?

 

[JohnD]

When I resigned from Brinks-MAT (I used to work in the Heathrow warehouse) I bought a small smelter for my garden workshop. Should I have told someone about it?

 

[DetlefSchmitz]

Bit like needing permission for an electric shower...

 

[stillp]

10kW? Probably you should ask your DNO. They might also increase your cutout fuse if you ask nicely.

 

[tireetim]

OK thanks for your suggestion sheds and stillp, will speak to the DNO about it and see if they can increase the fuse too. Assuming that gets resolved, would it be ok to just add a new RCD and MCB to the consumer unit and run it from that?

 

[JohnW2]

Assuming that gets resolved, would it be ok to just add a new RCD and MCB to the consumer unit and run it from that?

If you (or your electrician) feels it inappropriate to feed the new circuit from one of the existing RCDs, it would be simpler (and take up only one third of the space) to use a 45A RCBO (a combined MCB and RCD), assuming that one is available for your CU, rather than adding separate MCB and RCD.

Kind Regards, John

 

[ban-all-sheds]

No, didn't think it would be necessary. It's a private house and a hobby kiln. Would you need such permission for a range cooker or similar household appliance?

//www.diynot.com/diy/search/2263908/?q=permission&o=relevance&c[node]=8&c[user][0]=156979

 

[RF Lighting]

I wouldn't personally want to RCD protect a kiln.

 

[JohnW2]

I wouldn't personally want to RCD protect a kiln.

As a matter of interest, why not (assuming it was a dedicated RCD or, as I suggested, an RCBO)?

Kind Regards, John

 

[Taylortwocities]

It looks to me like all of the ways are already RCD protected,

80A RCD
32A MCB (Cooker)
20A MCB (sockets)
20A MCB (Sockets)
6A MCB (Lights)

80A RCD
32A MCB (Kitchen Sockets, ring)
20A MCB (Sockets)
6A MCB (Lights)
6A MCB (Lights)

so an MCB is all that is needed for the kiln circuit. (plus notification to LABC as its a new circuit)

However, the main fuse will need increasing from 60A if the kiln is really is 45A. I don't think that there are any diversity allowances for kilns?

I do agree that the kiln should not be RCD protected in the CU, as a dollop of wet clay may trip half the house out. If the CU is one of the so-called high integrity jobbies then a new MCB in the unprotected slot will do it, opther wise its a switch fuse and henleys.

 

[JohnW2]

It looks to me like all of the ways are already RCD protected, ...

They are, but the OP was consdiring adding a third RCD, just for the kiln, because he was concerned that the kiln (plus existing circuits) might overload an 80A RCD (even though he's only got a 60A supply). As I said to him, if he really wants dedicated RCD protection for the kiln, he should consdier a 45A RCBO.

I do agree that the kiln should not be RCD protected in the CU, as a dollop of wet clay may trip half the house out.

As above, AIUI, the proposal was for the kiln to have its own dedicated RCD (or RCBO), so the rest of the house would not be 'at risk'. Are there (as suggested by RF) any other reasons for not RCD-protecting a kiln.

Kind Regards, John

 

[RF Lighting]

There's no requirement to have an RCD. It's going to be a completely unnecessary device which may lead to problems.

 

[Robin0577]

There's no requirement to have an RCD. It's going to be a completely unnecessary device which may lead to problems.

There could, however, be a requirement for the kiln circuit cable to be RCD protected, depending on it's type and method of installation. Personally I would be inclined to agree with you and therefore I would choose a cable and installation method that avoids the requirement.