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Electrical fire in fuseboard

Does what it says on the tin
csearle
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Electrical fire in fuseboard

#402392

Postby csearle » April 7th, 2021, 6:17 pm

I did a test and inspection of a rental bungalow this morning. The neutral busbar had had either a small fire or a major overheating. Please see the picture below. This is usually because terminals are loose or have not been re-tensioned. In this case the neutral grub-screws were baked solid, all the others (including the incoming tails and the links between the main switch and the RCD) were able to be tightened up by about two whole turns each - some more.

I couldn't completely test the installation because whenever I moved the neutral wires insulation broke away. The bungalow had recently been bought. This situation went undiscovered during that process. It is only because the owner is renting it out temporarily and some new rules apply that insist on electrical test and inspections that it was discovered.

I will fail it.

Chris

ImageI own (or am legally permitted to post) the content of this image.

Mike4
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Re: Electrical fire in fuseboard

#402446

Postby Mike4 » April 7th, 2021, 10:07 pm

Worrying innit. I encounter this all the time. The copper of the wires seems to 'relax' a few years after being installed and make the screws go slack and high resistance.

Earns me quite a lot on money, fixing burned out power supplies to electric boilers. Callers often report a "smell of fish" in or around the boiler, which usually turns out to be a loose connection screw with krispy insulation next to it...

GrahamPlatt
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Re: Electrical fire in fuseboard

#402449

Postby GrahamPlatt » April 7th, 2021, 10:20 pm

It does seem to be a problem, the maleability of copper in this situation; biting down onto “tails” with a simple screw. Better methods are available.

AsleepInYorkshire
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Re: Electrical fire in fuseboard

#402450

Postby AsleepInYorkshire » April 7th, 2021, 10:25 pm

csearle wrote:I did a test and inspection of a rental bungalow this morning. The neutral busbar had had either a small fire or a major overheating. Please see the picture below. This is usually because terminals are loose or have not been re-tensioned. In this case the neutral grub-screws were baked solid, all the others (including the incoming tails and the links between the main switch and the RCD) were able to be tightened up by about two whole turns each - some more.

I couldn't completely test the installation because whenever I moved the neutral wires insulation broke away. The bungalow had recently been bought. This situation went undiscovered during that process. It is only because the owner is renting it out temporarily and some new rules apply that insist on electrical test and inspections that it was discovered.

I will fail it.

Chris

ImageI own (or am legally permitted to post) the content of this image.

I'm no electrician but doesn't the design of the board make it hard to work in? Does this fall under CDM?

Do the black wires touching at the top cause issues?

It's a frightening reality to witness this really.

AiY

AsleepInYorkshire
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Re: Electrical fire in fuseboard

#402451

Postby AsleepInYorkshire » April 7th, 2021, 10:35 pm

PS ....

Chris I've got you booked in for 10am next Monday morning for the solenoid watchamacallit.

Pay will be a cup of tea and a chocolate digestive (from the fridge mate)

AiY

csearle
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Re: Electrical fire in fuseboard

#402481

Postby csearle » April 8th, 2021, 2:57 am

AsleepInYorkshire wrote:I'm no electrician but doesn't the design of the board make it hard to work in?
It does. There is hardly any room to dress the wires in nicely* .In this case the consumer unit is at the back of a kitchen corner unit. The white at the very top of the picture is the underside of the kitchen work surface. It is a pig to get at. Won't be wholly sorry if I don't get the job of replacing the consumer unit. I suspect though that I will as the client is (was) one of my volleyball participants.

AsleepInYorkshire wrote:Does this fall under CDM?

Do the black wires touching at the top cause issues?
No the housing is plastic (no longer allowed in most domestic situations as they are considered a fire risk) so the ends of the wires often touch the enclosure. I think maybe some water could have leaked over the back edge of the work surface making the busbar wet, but that's just a guess. It could equally have started with an untight terminal. It is possible for there to be thermal runaway with the heat speeding up the corrosion, making the connection poorer, generating more heat, and so on.

Chris
*I use consumer units like this one at the moment because they have more space.

csearle
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Re: Electrical fire in fuseboard

#402482

Postby csearle » April 8th, 2021, 2:58 am

AsleepInYorkshire wrote:PS ....

Chris I've got you booked in for 10am next Monday morning for the solenoid watchamacallit.

Pay will be a cup of tea and a chocolate digestive (from the fridge mate)

AiY
Is this "Yorkshire" place anywhere near Kent? :)

AsleepInYorkshire
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Re: Electrical fire in fuseboard

#402488

Postby AsleepInYorkshire » April 8th, 2021, 7:53 am

csearle wrote:
AsleepInYorkshire wrote:PS ....

Chris I've got you booked in for 10am next Monday morning for the solenoid watchamacallit.

Pay will be a cup of tea and a chocolate digestive (from the fridge mate)

AiY
Is this "Yorkshire" place anywhere near Kent? :)

10 minutes away :lol:

AiY

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Re: Electrical fire in fuseboard

#402501

Postby bungeejumper » April 8th, 2021, 9:06 am

csearle wrote: I think maybe some water could have leaked over the back edge of the work surface making the busbar wet, but that's just a guess.

Oh yeah, water. How could I have forgotten that?

A lot of the houses in this village are owned by the local landed gentry (ancient family, hereditary baronets, huntin' and all that), and they're absolute skinflints about updating and maintaining their rental properties. A few years ago, one of the neighbours called me after her power failed, and sure enough, it was a small brown bakelite fuse box of probably sixty years' antiquity, all cracked and blistered. I told her to insist on getting it changed for a modern consumer unit. His lordship resisted for the best part of a year. To the best of my knowledge, my other neighbour still has hers in place. :|

How do they get away with it? In rental properties, too?

BJ


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