Electric Installation Queries

[cwcw]

It's the latter. Both MCBs have to be off for the sockets not to work.

Then it definitely needs attention. What are the ratings of the two MCB's concerned?

Both are 16. Incidentally it's this (these) circuit(s) plug the lawnmower into in summer....

Some other things that seem a bit weird to me (logically at least as I'm no electrician):

- One light circuit has just one light switch on it while another light circuit covers all upstairs, hallway and lounge (7 or 8 switches). Seems unbalanced.

- The boiler circuit has a spur off it for one socket in the kitchen (boiler isn't in kitchen). Other sockets in the kitchen are on another circuit.

 

[cwcw]

Inside the sockets of the room, I'm not sure but they appear to be connected to two circuits. This would explain why there are two MCBs. Why would this be and what are the dangers?

 

[EFLImpudence]

Both are 16. Incidentally it's this (these) circuit(s) plug the lawnmower into in summer....

It would be more beneficial to at least RCD these sockets than upstairs - if you are not going to do them all.

One light circuit has just one light switch on it while another light circuit covers all upstairs, hallway and lounge (7 or 8 switches). Seems unbalanced.

Bit odd. I would assume it has been put in or altered lately.
At least you have one light should the other circuit trip.

The boiler circuit has a spur off it for one socket in the kitchen (boiler isn't in kitchen). Other sockets in the kitchen are on another circuit.

How do you know the boiler isn't spurred off this socket circuit?

 

[EFLImpudence]

Inside the sockets of the room,

I'm not sure but they appear to be connected to two circuits. This would explain why there are two MCBs. Why would this be and what are the dangers?

If they are on two separate circuits then it doesn't matter.
Does one of the sockets still work when one breaker is turned off?

As they are both 16A protected, there is no apparent danger.

 

[cwcw]

Inside the sockets of the room,

I'm not sure but they appear to be connected to two circuits. This would explain why there are two MCBs. Why would this be and what are the dangers?

If they are on two separate circuits then it doesn't matter.
Does one of the sockets still work when one breaker is turned off?

As they are both 16A protected, there is no apparent danger.

All 3 sockets still work with either or both 16amp breaker on, and all 3 don't work when they are both off. By inside the sockets I meant after taking off the plates to have a look..... appears to be 2 separate circuits feeding each one. Why would this be done?

Ps. Both are on the RCD.

 

[PBC_1966]

All 3 sockets still work with either or both 16amp breaker on, and all 3 don't work when they are both off.

Then there is a cross-connection between the two circuits which needs to be put right.

By inside the sockets I meant after taking off the plates to have a look..... appears to be 2 separate circuits feeding each one. Why would this be done?

You mean two cables connected to each socket? That's normal where one cable is bringing power into the socket and another then continues on to other sockets.

But in your case, there is a cross-connection between two circuits which shouldn't be there, so certainly at some point you must have the two circuits coming together.

 

[Adam_151]

But in your case, there is a cross-connection between two circuits which shouldn't be there, so certainly at some point you must have the two circuits coming together.

Noting the following points:

a) Its a 1970's extension
b) The Cu has RCD protection to some circuits
c) The breakers concerned are both 16A
d) All sockets appear to have two cables at them

It looks as if sometime in the past someone has ballsed up a CU change and connected legs of a ring thinking they were 2 radials

 

[PBC_1966]

Yes, I agree that certainly sounds like a strong possibilty. Further investigation needed.

 

[cwcw]

Thanks guys. If that is the case, what level of risk/danger is it? Big job for an electrician to fix?

 

[kai]

It looks like a diy consumer unit replacement job from the sounds of it.

 

[Adam_151]

To borrow from the terminology from another industry... it is "At risk" but not "immediatly dangerous"

One should consider scheduling work to have it attended to at earliest convenience

If its as I suspect, its a simple job... well it would be to move it onto one of the two 16A breakers... as to moving the ring (providing I'm right and it is one) onto a 32A. It will depend on whether a 32A can be sourced for your consumer unit.... what make is it? (Or even better, take a photograph of it)

 

[cwcw]

To borrow from the terminology from another industry... it is "At risk" but not "immediatly dangerous"

One should consider scheduling work to have it attended to at earliest convenience

If its as I suspect, its a simple job... well it would be to move it onto one of the two 16A breakers... as to moving the ring (providing I'm right and it is one) onto a 32A. It will depend on whether a 32A can be sourced for your consumer unit.... what make is it? (Or even better, take a photograph of it)

It's a Volex VCU6. I'm not sure I understand what you mean though. Can't one of the two 16amp circuits just be disconnected and capped off?

I don't think it was a DIY replacement as I'm pretty sure it it was done as part of the electrical works before we bought it. I have the paperwork but filed it in the loft with all the other house buying stuff "somewhere" - will have to dig it out!

 

[Midas Man]

Weren't Volex recalled some time ago?

 

[Adam_151]

Weren't Volex recalled some time ago?

There were a load of wylex, volex and crabtree 6/10 and 16A MCBs recalled around 2010.

If the OP had one on a socket circuit he'd have known about it by now though.... the issue was a high resistance in the breaker contacts leading to heating happening within. I've seen faulty breakers come out which were melted to the ones either side and had to be removed as a block of three!

 

[Iggifer]

Weren't Volex recalled some time ago?

Yea but not every Volex breaker ever. It was just VB16, VB10 and VB06.