Fused connection unit burnt out

[boringoldcodger]

I changed the bayonet fitting in the downstairs hallway last week as I had enough of it fouling on the front door every time it was opened to a flush fit and found that it ....... have been wired into the upstairs lighting circuit and not the downstairs one.

I believe this might be to avoid the "borrowed neutral" problem. If you've got 2-way switching and the upstairs lights are on a different RCD to the downstairs lights, then it's possible for a light to take it's power from the upstairs circuit but to have it's neutral wire on the downstairs circuit (or vice versa) and so the RCDs will see a current mismatch and will trip.

 

[Kerryw92]

I believe this might be to avoid the "borrowed neutral" problem. If you've got 2-way switching and the upstairs lights are on a different RCD to the downstairs lights, then it's possible for a light to take it's power from the upstairs circuit but to have it's neutral wire on the downstairs circuit (or vice versa) and so the RCDs will see a current mismatch and will trip.

Single switch on both the kitchen and this light. Didn't know about the borrow neutral issues however so thanks for the info.

Not conventional, but why should it be a problem?

Just thought cooker, hob, extractor & central heating would be a bit too much really. Every home before this has had central heating separated.

You don't need an FCU, the appliance plugs have fuses.

Running new circuits is notifiable work.

Cheers, wasn't aware it was notifiable. Thought it would be if running to outdoor power etc but will look into it all first.

Just a thought - Is the twin socket below a worktop and the FCU above it and able to be used as an isolator?

Yeah that's exactly how it is, FCU above worktop and sockets it isolates are in the cupboard below the sink. Same layout has been adopted to the built it fridge and freezer at the other side of the room.

 

[Harry Bloomfield]

Just thought cooker, hob, extractor & central heating would be a bit too much really. Every home before this has had central heating separated.



Cheers, wasn't aware it was notifiable. Thought it would be if running to outdoor power etc but will look into it all first.



Yeah that's exactly how it is, FCU above worktop and sockets it isolates are in the cupboard below the sink. Same layout has been adopted to the built it fridge and freezer at the other side of the room.

It sounds as if it has all been done on the cheap, sharing circuits to minimise installation cost - a botch. Not acceptable on a new build.

I wouldn't expect problems with the fridge and freezer sharing the FCU. Even as used as an isolator, there is no reason why it should be fused, an FCU. More sensible would have been a 20amp unfused isolator, allowing full use of both of the sockets. There would be nothing unusual in wanting to run a washing m/c and a dishwasher simultaneously, so it a ridiculous restriction. JohnW2 will be along soon, to give his more expert opinion - he is more familiar with domestic arrangements.

Is it/was it a national builder, or a small local one?

 

[Kerryw92]

It sounds as if it has all been done on the cheap, sharing circuits to minimise installation cost - a botch. Not acceptable on a new build.

I wouldn't expect problems with the fridge and freezer sharing the FCU. Even as used as an isolator, there is no reason why it should be fused, an FCU. More sensible would have been a 20amp unfused isolator, allowing full use of both of the sockets. There would be nothing unusual in wanting to run a washing m/c and a dishwasher simultaneously, so it a ridiculous restriction. JohnW2 will be along soon, to give his more expert opinion - he is more familiar with domestic arrangements.

Is it/was it a national builder, or a small local one?

Thanks, luckily if any more issues arise they still need to carry out the remedial work free of charge as per the warranty agreement anyway.

All local firms were contracted in and the building firm is a local one too. Glad about this as any issues so far have been resolved either the same day or next day if waiting on parts.

 

[bernardgreen]

An isolator is not required above the worktop.

Isolation is available at your CU.

It is not required by the regulations and therefore Winston believes and advocates that it is un-necessary to have local isolation for appliances.

He might change his mind if he ever has to cope a smoking washing machine that can only be isolated at the CU. In this situation Winston might be strong and able to pull the washing machine far enough forward to get behind the machine to pull the plug out. He can then go back to the CU and restore power the kitchen.

Other people may not be able to get to the plug on the wall and thus may have to wait until help arrives before they can have power restored in the kitchen.

 

[securespark]

House is wired to allow the two appliances to be running simultaneously.
Spark says the problem was caused by allowing the two appliances to run simultaneously.

That makes sense.

 

[Harry Bloomfield]

House is wired to allow the two appliances to be running simultaneously.
Spark says the problem was caused by allowing the two appliances to run simultaneously.

That makes sense.

Makes no sense at all to me, to make such a pointless restriction. The electrician or who ever designed the system, imposed an unnecessary restriction on the circuits normal use. You don't buy ant 140mph car, then be told it should not be driven at more than 70mph.

 

[securespark]

Er.... yes, you do!

 

[Harry Bloomfield]

Er.... yes, you do!

Sorry, you are not really making much sense - 'do' what?

 

[securespark]

You do buy cars that are able to exceed the NSL yet are told it should not be driven at more than 70mph...

 

[Harry Bloomfield]

You do buy cars that are able to exceed the NSL yet are told it should not be driven at more than 70mph...

Not by the manufacturer or the seller of the car.

 

[winston1]

It is not required by the regulations and therefore Winston believes and advocates that it is un-necessary to have local isolation for appliances.

He might change his mind if he ever has to cope a smoking washing machine that can only be isolated at the CU. In this situation Winston might be strong and able to pull the washing machine far enough forward to get behind the machine to pull the plug out. He can then go back to the CU and restore power the kitchen.

Other people may not be able to get to the plug on the wall and thus may have to wait until help arrives before they can have power restored in the kitchen.

Have you ever come across a smoking washing machine? Have you ever heard about these dangerous situations in Europe where local isolation is not used?
Why confine it to kitchen appliances? Why not have isolators for all the other appliances around the house such as TVs, set top boxes, computers, table lamps etc any of which could also start smoking.

 

[bernardgreen]

Why not have isolators for all the other appliances around the house such as TVs, set top boxes, computers, table lamps etc any of which could also start smoking.

Almost all of these will have a plug that can probably be easily removed from an accessible socket which may also have a switch.

Have you ever come across a smoking washing machine?

Only after it had stopped smoking.

Have you ever heard about these dangerous situations in Europe where local isolation is not used?

Yes, In Munich the flat belonging to a colleague's girlfriend was burnt out when an electric shower caught fire.

Just accept that your opinion is not the only option.

 

[Kerryw92]

To confirm the FCU has now been replaced. He backtracked on his word about running two appliances after he looked at the connections and admitted the live was not secured down adequately which he says more than likely caused the issue in the first place.

He did also mention the firm that did the install on the entire estate is no longer contracted to do any more remedial work due to various issues with multiple houses.

Kindly checked the few loose sockets for me and assured they were all good & fitted the missing blanks in the consumer unit too.

 

[EFLImpudence]

Thank you for letting us know.