Wylex type 2 MCB's

[ericmark]

I think you have missed the point. The MCB protects the cable before changing an MCB you need to inspect and test to find out the current rating of the cable.

I have not worked on that type of board for some time and some boards will allow you to simply swap one MCB others you need to basic strip the board and rebuild as once the MCB is clipped in you can't reach the clip to release it without stripping board.

The DNO fuse can be 60, 80, or 100 and if 60 then a 63A RCD on all circuits is not a problem. If it's 100 then it could be. There is no simple answer.

However step one is the readings we expect 1.37Ω impedance with a 32A B type and 1.09Ω with a 40A B type to assume it was 1.37Ω because a 32A MCB is already fitted is one thing, but to cross your fingers and hope it is within the 1.09Ω is something else. The same applies to the route, to assume it is such that cable is good for 32A as already fitted with 32A is one thing, to cross your fingers and pray it's OK for 40A is clearly not the way to do things.

In my house when the cavity wall insulation was fitted I was very careful to insure the installers did not put it where I know cables are in the cavity. But likely most houses now have de-rated cables due to cavity wall and loft insulation. To swap a 32A for a 40A MCB is not as easy as undoing and tightening screws.

 

[steve6501]

How much dismantling will I have to do on the board to swap for a 40A mcb, please? Can it be done with the board in place?

 

[securespark]

I can only find type B or type 1 breakers on the net.

But there must be type 2 around.

 

[JohnW2]

Looks like three x 6mm², two ring finals plus immersion heater (?), all on 63A RCD.

Indeed. I'd be interested to know what the third 6mm² circuit is. We know that one is the shower, and another is probably a cooker circuit, but I wonder what the third might be - the supply to an 'outhouse', perhaps?

Kind Regards, John

 

[JohnW2]

I can only find type B or type 1 breakers on the net. But there must be type 2 around.

Would a Type B not be an acceptable alternative to a Type 2?

Kind Regards, John

 

[Adam_151]

Can it be done with the board in place?

Yes, its a 2 minute job, but should not be done without checking that it is appropiate to do so

 

[steve6501]

Looks like three x 6mm², two ring finals plus immersion heater (?), all on 63A RCD.

Indeed. I'd be interested to know what the third 6mm² circuit is. We know that one is the shower, and another is probably a cooker circuit, but I wonder what the third might be - the supply to an 'outhouse', perhaps?

Kind Regards, John

The 3rd 6mm is another shower at 7.5 kW in another bathroom

Steve

 

[seasickstevie]

Have you ever tried having two showers at the same time whilst cooking the Sunday roast?

 

[flameport]

This is a new 40A MCB which will fit: http://www.ebay.co.uk/itm/281859990277
There are various dubious used examples for less.

However just replacing it is not an option for the reasons already given by others.

Yes, but it was OK'd when we bought the house five years ago

By who, and did they actually look at anything?

Two electric showers is bad enough on it's own, then there is the incorrect rating of MCB (which has now failed) and the obviously overloaded 63A RCD.
The lack of RCDs for the lighting circuits should also have been mentioned, as should the missing sleeving on some of the CPCs (earth wires), unsealed holes in the top of the enclosure and that black unsupported flex at the top right.
After that, there is the rest of the installation to examine.

That type of consumer unit should not be switched on with the lid removed, as all of those exposed terminals are live.

 

[securespark]

Have you ever tried having two showers at the same time whilst cooking the Sunday roast?

Doesn't the beef get soggy?

 

[PBC_1966]

By who, and did they actually look at anything?

Maybe one of those "check it all" home inspectors? They might be good for some things, but they often don't have the more than a basic knowledge of what to look for in the electrical installation, or test beyond plugging their 3-light tester into an outlet.