Just how common are consumer unit fires ?
Discussion
We all seem to be being told to upgrade consumer units to the current (no pun intended) regulations, i.e. the metal ones, due to fire risk.
Just how common are consumer unit fires ? Clearly a new metal one, with correctly sealed cable glands etc, wouldn't melt if a fire stared inside, that could then spread. Just how common are such fires though ?
What's the cause, faulty isolator/MCB/RCD, or loose connection that starts arcing? Is the potential (again, no pun intended) source of the fires any less with current regulation CUs ?
Imagine my surprise though on a CU change that the spark then puts an additional new double pole isolator in the meter box that's all plastic, including the case (Hager VC02SW). It's the same 100A DP isolator that's in the new CU, but in a plastic enclosure. All mounted on a bit of MDF in a fibreglass meter box. All nice and flammable. I asked that isn't that just as like to suffer an inferno inducing failure as the new CU, and was met with a shrug and some intangible references to standards.
I'm not belittling any of this, which is doubtless an improvement on safety and clearly installed to a higher standard than the 20 year old CU that it replaced, but just how common are the CU fires that prompted this change in standards ? Genuinely interested if anyone has experienced such a fire or similar fault.
Just how common are consumer unit fires ? Clearly a new metal one, with correctly sealed cable glands etc, wouldn't melt if a fire stared inside, that could then spread. Just how common are such fires though ?
What's the cause, faulty isolator/MCB/RCD, or loose connection that starts arcing? Is the potential (again, no pun intended) source of the fires any less with current regulation CUs ?
Imagine my surprise though on a CU change that the spark then puts an additional new double pole isolator in the meter box that's all plastic, including the case (Hager VC02SW). It's the same 100A DP isolator that's in the new CU, but in a plastic enclosure. All mounted on a bit of MDF in a fibreglass meter box. All nice and flammable. I asked that isn't that just as like to suffer an inferno inducing failure as the new CU, and was met with a shrug and some intangible references to standards.
I'm not belittling any of this, which is doubtless an improvement on safety and clearly installed to a higher standard than the 20 year old CU that it replaced, but just how common are the CU fires that prompted this change in standards ? Genuinely interested if anyone has experienced such a fire or similar fault.
I don’t know any stats, but changing a plastic thing that can’t conduct the electrical components in case of failure to something that can makes my butt clench a bit.
I am sure (well hope) there is decent data, but it seems like a win for the industry rather than a win for the punter. “Sorry mate, it’s the regs, I have to put in a new unit”….
I am sure (well hope) there is decent data, but it seems like a win for the industry rather than a win for the punter. “Sorry mate, it’s the regs, I have to put in a new unit”….
We had a fire in our consumer unit last year, I posted about it here: https://www.speakev.com/threads/a-cautionary-tale-...
I agree with you that it could also occur in the meter cupboard prior to the consumer unit, if the loose terminal was in the isolation switch or meter itself. In my situation I would have greatly appreciated the presence of an isolation switch, so I would say the benefit of having one outweighs the slight additional risk due to the additional potential points of failure at the connections.
I think that with the increasing popularity of EV charge points it will expose any weak points of existing electrical installations like this, as they are now handling substantial current draw for long sustained periods, and usually when the occupants are sleeping. Smoke detectors located in vulnerable areas are a must.
I agree with you that it could also occur in the meter cupboard prior to the consumer unit, if the loose terminal was in the isolation switch or meter itself. In my situation I would have greatly appreciated the presence of an isolation switch, so I would say the benefit of having one outweighs the slight additional risk due to the additional potential points of failure at the connections.
I think that with the increasing popularity of EV charge points it will expose any weak points of existing electrical installations like this, as they are now handling substantial current draw for long sustained periods, and usually when the occupants are sleeping. Smoke detectors located in vulnerable areas are a must.
I've seen a few over the years mainly burnt out isolators and dis boards, I'm more industrial and don't see much domestic but majority of time it is loose connection through poor initial installation followed by lack of inspection or overuse of LIM when they do inspect.
This is my place, timber frame 90's new build. I noticed an odd smell over a couple of days and couldnt work out wthat it was. My four year old woke us up one morning saying something about buring, went down to find dining room full of smoke. An early Crabtree recessed all metal unit.
Merit of metal v plastic I would always choose metal but that is only part of it. The fire proofing on entry points, strain relief on incoming tails wasn't something you saw on early domestic boards. That said, no excuse for bad workmanship, tails on this board are 3M to meter. Originally ran horizontal, vertical and 45 degrees from meter box to CU through the timber frame, full on friday afternoon effort. They were pulled super tight to reach, over time the copper relaxes and the tails come become loose. If it was installed correctly and inspected you dramatically reduce the risk.
This is my place, timber frame 90's new build. I noticed an odd smell over a couple of days and couldnt work out wthat it was. My four year old woke us up one morning saying something about buring, went down to find dining room full of smoke. An early Crabtree recessed all metal unit.
Merit of metal v plastic I would always choose metal but that is only part of it. The fire proofing on entry points, strain relief on incoming tails wasn't something you saw on early domestic boards. That said, no excuse for bad workmanship, tails on this board are 3M to meter. Originally ran horizontal, vertical and 45 degrees from meter box to CU through the timber frame, full on friday afternoon effort. They were pulled super tight to reach, over time the copper relaxes and the tails come become loose. If it was installed correctly and inspected you dramatically reduce the risk.
There's been an aparent tenfold increase in consumer unit fires but they're still pretty rare - 10x not much is still not much.
IMO it can be mostly traced to the increase in electrical work being carried out in recent years by quite poorly skilled persons. In years gone by if you needed electrical work you'd get someone who does that but there's been a massive rise in the use of willing and economically competitive "do-anythingers" to refurbish etc.
The problem is the IEE (who set electrical regs) are so comprehensively detached from the reality they think imposing new rules on those who follow rules will effect the consequences of those who are probably incapable of even reading the regs.
IMO it can be mostly traced to the increase in electrical work being carried out in recent years by quite poorly skilled persons. In years gone by if you needed electrical work you'd get someone who does that but there's been a massive rise in the use of willing and economically competitive "do-anythingers" to refurbish etc.
The problem is the IEE (who set electrical regs) are so comprehensively detached from the reality they think imposing new rules on those who follow rules will effect the consequences of those who are probably incapable of even reading the regs.
b.e.n.n.y_b.o.y said:
We had a fire in our consumer unit last year, I posted about it here: https://www.speakev.com/threads/a-cautionary-tale-...
I agree with you that it could also occur in the meter cupboard prior to the consumer unit, if the loose terminal was in the isolation switch or meter itself. In my situation I would have greatly appreciated the presence of an isolation switch, so I would say the benefit of having one outweighs the slight additional risk due to the additional potential points of failure at the connections.
I think that with the increasing popularity of EV charge points it will expose any weak points of existing electrical installations like this, as they are now handling substantial current draw for long sustained periods, and usually when the occupants are sleeping. Smoke detectors located in vulnerable areas are a must.
Crikey, that's very scary. Great write up on the EV site BTW. What a mess it made. Glad to hear damage was limited, and the various firebreaks did their job.I agree with you that it could also occur in the meter cupboard prior to the consumer unit, if the loose terminal was in the isolation switch or meter itself. In my situation I would have greatly appreciated the presence of an isolation switch, so I would say the benefit of having one outweighs the slight additional risk due to the additional potential points of failure at the connections.
I think that with the increasing popularity of EV charge points it will expose any weak points of existing electrical installations like this, as they are now handling substantial current draw for long sustained periods, and usually when the occupants are sleeping. Smoke detectors located in vulnerable areas are a must.
b.e.n.n.y_b.o.y said:
We had a fire in our consumer unit last year, I posted about it here: https://www.speakev.com/threads/a-cautionary-tale-...
I agree with you that it could also occur in the meter cupboard prior to the consumer unit, if the loose terminal was in the isolation switch or meter itself. In my situation I would have greatly appreciated the presence of an isolation switch, so I would say the benefit of having one outweighs the slight additional risk due to the additional potential points of failure at the connections.
I think that with the increasing popularity of EV charge points it will expose any weak points of existing electrical installations like this, as they are now handling substantial current draw for long sustained periods, and usually when the occupants are sleeping. Smoke detectors located in vulnerable areas are a must.
That is scary and you were lucky to get out of that!I agree with you that it could also occur in the meter cupboard prior to the consumer unit, if the loose terminal was in the isolation switch or meter itself. In my situation I would have greatly appreciated the presence of an isolation switch, so I would say the benefit of having one outweighs the slight additional risk due to the additional potential points of failure at the connections.
I think that with the increasing popularity of EV charge points it will expose any weak points of existing electrical installations like this, as they are now handling substantial current draw for long sustained periods, and usually when the occupants are sleeping. Smoke detectors located in vulnerable areas are a must.
I think i am perfectly capable of doing electrical bits around the house but anything to do with the fuse box i get an electrician in.
jollysoutherner said:
I've seen a few over the years mainly burnt out isolators and dis boards, I'm more industrial and don't see much domestic but majority of time it is loose connection through poor initial installation followed by lack of inspection or overuse of LIM when they do inspect.
This is my place, timber frame 90's new build. I noticed an odd smell over a couple of days and couldnt work out wthat it was. My four year old woke us up one morning saying something about buring, went down to find dining room full of smoke. An early Crabtree recessed all metal unit.
Merit of metal v plastic I would always choose metal but that is only part of it. The fire proofing on entry points, strain relief on incoming tails wasn't something you saw on early domestic boards. That said, no excuse for bad workmanship, tails on this board are 3M to meter. Originally ran horizontal, vertical and 45 degrees from meter box to CU through the timber frame, full on friday afternoon effort. They were pulled super tight to reach, over time the copper relaxes and the tails come become loose. If it was installed correctly and inspected you dramatically reduce the risk.
Wow, another scary account. Lucky you caught it when you did.This is my place, timber frame 90's new build. I noticed an odd smell over a couple of days and couldnt work out wthat it was. My four year old woke us up one morning saying something about buring, went down to find dining room full of smoke. An early Crabtree recessed all metal unit.
Merit of metal v plastic I would always choose metal but that is only part of it. The fire proofing on entry points, strain relief on incoming tails wasn't something you saw on early domestic boards. That said, no excuse for bad workmanship, tails on this board are 3M to meter. Originally ran horizontal, vertical and 45 degrees from meter box to CU through the timber frame, full on friday afternoon effort. They were pulled super tight to reach, over time the copper relaxes and the tails come become loose. If it was installed correctly and inspected you dramatically reduce the risk.
They are indeed more common than I thought, I think Benny has a point too that large loads over long periods will show up any weakness or high resistance that could start something like this.
On Benny's other site's thread there's a comment about putting a linked smoke alarm in a loft space, as there's services in those too. That's a good idea I've never thought of or seen before.
Edited by catfood12 on Wednesday 29th September 13:04
jollysoutherner said:
If it was installed correctly and inspected you dramatically reduce the risk.
This is why it is recommended to inspect every 5 years, screw terminals by their very nature work loose, if you overtighten them it can actually make matters worse!As for not liking the idea of a metal enclosure, if the installation is done correctly no more dangerous than a plastic enclosure. A lot of older switch gear & industrial stuff is/was metal.
Several years ago I had a fire at a student HMO rental property. The consumer unit was newly installed by a reputable electrician. Apparently the fire was caused by tails entering the consumer unit shorting, creating the fire to spread along wires leaving the unit, causing several thousand pounds of damage. Fortunately the fire started both in the day time, and when tenants were awake and in occupation.
catfood12 said:
Crikey, that's very scary. Great write up on the EV site BTW. What a mess it made. Glad to hear damage was limited, and the various firebreaks did their job.
Certainly focus the mind a little.We have a new metalclad consumer unit, but did also install a smoke detector next to it, which also covers the tumble drier and washing machine, which are in the same utility room area while we where ding a full re-wire and fitting interlinked fire alarms.
Daniel
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