MCB Wiring doubt

[smudger]

Hello Proper Electricians.

Hoping for a bit of advise. I'm a plumber with Part P domestic qual, but haven't done a lot since taking exams. Just fitted a kitchen and when it came to installing microwave, discovered it was 3.4kw with 3.25kw cooker and gas hob therefore about 25a. Think regs ok with wiring both through existing 45a dp as within 2m, but don't want appliance on 45a fuse. So thought best option to put on individual 16a mcbs. So far so good I hope. However, started to doubt myself on wiring as I haven't done one for ages and can't find wiring diagram in my notes (also can't find my osg). I have taken two radials to mcbs and two cables to CU's for appliances. Am I right that I connect all earths to earth block, neutrals to neutral block, incoming lives to top of mcb, outgoing to appliance from bottom? If I'm well off I let me know and I will speak to electrician tomorrow, but if anyone knows where I can see wiring diagram I would be really grateful.

 

[smudger]

As far as I can make out, my solution to the problem is correct. If you guys would have done differently please tell me. The mic may have run on a 13amp according to diversity (max 13.25a) but it'd probably keep trippping, and as the cooker was a max of 14.2a I didn't want it on a 45a fuse. So I don't see what's wrong with having them on individual 16a breakers. Seems like a good solution, there both on the 32a dedicated radial. AM I missing something? MAybe my language gave the impression I don't know what I'm talking about, but I do get it. Just in a bit of a corner and was hoping for some help.

 

[smudger]

thank you Dave. I appreciate that vary much

 

[Dave 85]

As far as I can make out, my solution to the problem is correct. If you guys would have done differently please tell me. The mic may have run on a 13amp according to diversity (max 13.25a) but it'd probably keep trippping, and as the cooker was a max of 14.2a I didn't want it on a 45a fuse. So I don't see what's wrong with having them on individual 16a breakers. Seems like a good solution, there both on the 32a dedicated radial. AM I missing something? MAybe my language gave the impression I don't know what I'm talking about, but I do get it. Just in a bit of a corner and was hoping for some help.

Im confused now....
Are they on a 45 amp, two 16 amps or a 32amp dedicated radial?
For the record a 13 amp fuse wont pop when you put 13.25 amps down it. Infact I think you could happily pass at least 20 down it for quite a while.

 

[Des 56]

Im confused now....
Are they on a 45 amp, two 16 amps or a 32amp dedicated radial?
For the record a 13 amp fuse wont pop when you put 13.25 amps down it. Infact I think you could happily pass at least 20 down it for quite a while.

I had that affliction after smudgers first description

 

[trev]

Easy now guys, like Tel said the post where he says "but your probably right. I'll get him in."
I'm not looking forward to the day I have to ask a question

 

[smudger]

Im confused now....
Are they on a 45 amp, two 16 amps or a 32amp dedicated radial?
For the record a 13 amp fuse wont pop when you put 13.25 amps down it. Infact I think you could happily pass at least 20 down it for quite a while.

The cooker was going to be reconnected to the 45dp cooker socket that was there originally. But the guy has had a 3.4kw Neff cooker and 3.2kw combination microwave installed. The cooker was on its own radial with 32a protection in consumer unit.

I had originally been asked to add 13amp socket into main kitchen ring for microwave. However, the whole house is run on two rings, a 16a and a 32a. As there is a dishwasher, washine machine, tumble dryer, 2 x ufh (plus all sorts of other stuff) already on the rings, I was concerned about adding another 3.25kw appliance.

Also, as the appliances were very expensive I was concerned about having the appliances wired through the existing cooker outlet as it is 45a rated.

So I thought (and still do) that the best solution was to put the two appliances on individual 16a mcb. I have used 2.5mm surface clipped cable, with appliances hard-wired into 20a non-fused connection units.

The supply has been taken with 10mm t&e into 40a jb, and feed for mcb taken from there.

Hope this is clear.

 

[Geoffsd]

as the appliances were very expensive I was concerned about having the appliances wired through the existing cooker outlet as it is 45a rated.

It's the 32Amcb that counts - not the 45A switch.
The fuse is to protect the cable. You could have a 40W light on the end.

So I thought (and still do) that the best solution was to put the two appliances on individual 16a mcb. I have used 2.5mm surface clipped cable, with appliances hard-wired into 20a non-fused connection units..

You could connect them both to the cooker circuit but if you use smaller (than 4mm) cable/flex this will have to be protected by an appropriately sized fuse.

 

[VoltzElectrical]

In the light of all subsequent responses, I see now that smudger knows more than enough to safely carry out electrical work. However, my post was not meant to be unfriendly and to be honest, the OP was so badly worded, what else did he expect?

I'm leaving this thread now, good luck.

 

[telectrix]

if i were doing it, and i hope i've not misread the situation, i would wire the cooker to the 45A cooker switch,on a 32A MCB, and run a 16A radial to the microwave. this leaves the facility to upgrade the cooker in the future.

 

[Rockingit]

^^^ what he said.