Consumer unit wired incorrectly?

[fenzi]

Hi all,

My house is one that had a double storey extension built about 10 years ago, and a CU was installed to power that side of the house, which consists of a bedroom, bathroom and the kitchen. The rest of the house is using an older style fuse box that has the rewireable BS3036 fuses. (2 x 5A, 1 x 15A, 1 x 30A)

Upon checking the fuses one day I noticed that the 15A fuse was wired using a single piece of 2.5mm copper wire

Naturally I thought this was incorrect and hazardous so I replaced this with 15A fuse wire which is when the fun started. Now if I have too many appliances on at the same time, e.g. oven, microwave, tumble dryer -- the fuse will blow and require rewiring. This is getting to the point where it's inconvenient and annoying and I am thinking that maybe the newer CU is wired up to the single fuse which is why it keeps overloading and blowing. The fuse is also extremely hot when it does go and I have to let it cool down before I can take it out.

My question is what should have been done when the CU was installed so that it was done correctly, and how much of a job is it as money is a bit tight at the minute!

Thanks for reading

 

[holmslaw]

..

 

[ban-all-sheds]

Naturally I thought this was incorrect and hazardous

You were right.

so I replaced this with 15A fuse wire which is when the fun started. Now if I have too many appliances on at the same time, e.g. oven, microwave, tumble dryer -- the fuse will blow and require rewiring.

So now you know why he replaced the fuse wire with something a lot thicker.

This is getting to the point where it's inconvenient and annoying and I am thinking that maybe the newer CU is wired up to the single fuse which is why it keeps overloading and blowing.

Yup.

The fuse is also extremely hot when it does go and I have to let it cool down before I can take it out.

It would be.

Also, when it wasn't a fuse it would have been passing a lot of current - it's quite possible that the fuse contacts have been damaged.

My question is what should have been done when the CU was installed so that it was done correctly,

It should have been supplied directly from the meter tails, just like the original fusebox is.

and how much of a job is it as money is a bit tight at the minute!

You need to get someone to look at it all.

Is the extension CU next to the original, or distant from it?

Could the cable supplying it be replaced? The thing is I find it hard to imagine that a proper electrician would have put the new CU on a 15A fuse, or would have replaced that with something the equivalent of about an 80A fuse.

The cable supplying the new CU may well be undersized, and who knows what kind of a mess the IDF made of the wiring in the extension.

For your own safety you should get the whole lot checked out. The fact that it has apparently been OK for 10 years means very little, I'm afraid.

 

[AndyPRK]

when this fuse blows, does nothing in the extension work ?

 

[xr4x4]

You need to start pulling out the fuses and see what powes what.

2x 6a, 15a, 30a seems a bit odd.

The old 4 ways were normally, 6a lights, 15a immersion, 30a sockets, 30a cooker circuit.

Maybe someone's been DIYing with the circuits and fuses.

 

[ban-all-sheds]

I don't think there's any "maybe" about it....

 

[fenzi]

Yep, when the fuse blows there is no power to any part of the extension at all. I was told that all the work had been done by a 'qualified' electrician who also did work in other areas of the house so I'm sure this won't be the last of it

Thanks for confirming my worst fears, looks like I'll be calling someone in.

 

[ericmark]

Although not correct I have seen where 15A carriers have been used in 32A bases and with re-wireable one can fit any size of fuse wire. In fact common to see a fuse carrier with a link bar used in the neutral.

It needs inspecting to find out what size cable has been used. Clearly not following the rules, but to guess is dangerous it may need a complete re-wire because it's been overloaded for so long but also it could be just used the wrong size fuse carrier.

You will not get your answers here you need some one to physically inspect and see what you have.

 

[ban-all-sheds]

So now you know why he replaced the fuse wire with something a lot thicker.

Except I didn't write that.

I wrote a much more accurate description of the person who has possibly put the current occupants' lives at risk than "he", a description which was designed to leave the OP in no doubt as to what that person was.

Apparently we mustn't have that - we must just say things like "oh dear, that's not quite right", or "it may be that he didn't really get it right".

FFS.

 

[RF Lighting]

I reported your post to the moderators because there was absolutely no need what so ever for use of abusive language like you used.

I thought you were a well educated chap. Surely your vocabulary extends beyond such malediction?

 

[securespark]

It happens often and it upsets me.

As you say, surely there are better words that can be used and no need to get personal about it either.

 

[ban-all-sheds]

I reported your post to the moderators because there was absolutely no need what so ever for use of abusive language like you used.

The IDF who did what the OP describes deserved every word of it and more.

And the OP deserved to be left in no doubt about the level of skill displayed by that person.

I thought you were a well educated chap. Surely your vocabulary extends beyond such malediction?

My vocabulary does, and by definition "extending beyond" means "incorporating".