EICR Electrical report

GDB2222

I don't see any reason why the wiring shouldn't go on another 25 years!  As I said, we have some wiring in the family that I know was done 48 years ago, and there seems to be no reason to change it.

For example there's an opinion here saying up to 70 years is okay:
https://www.mybuilder.com/questions/v/6998/at-what-age-of-house-should-re-wiring-be-considered

TheProfessional

That's an interesting read thanks. He didn't turn up this afternoon to chat about the C2 jobs so maybe another time

For now we will add the sockets and change light fittings along with the other bits picked up. Maybe looking to see if there is a better electrician out there by the sounds of it

Might have a few questions once they have been so tha is for advice so far

GDB2222

Mickey666 said:

TheProfessional said:

That's true. I don't know if it would feel worth it if everything is working well though. I wonder whether £3k now is better than £3k in a decade. If the wires are 25 years old and they could I suppose go on another 10 years or they could fail earlier than that

With a modern CU (ie RCD etc), what's the actual danger of failing wiring?  Obviously there will be nuisance tripping and perhaps even a permanent inability to use a particular circuit, but would there be any actual danger to life or property?

I ask, because if there is no danger to life or property, what would be the point of rewiring if the installation can still pass an ECIR even though the wiring is old?

It can be a fire risk as well as an electrocution risk. It's possible a junction could overheat without tripping an RCD, for example?  I'm sure that @Risteard has a better idea.

I had a painter working in my house. He borrowed my extension lead (on a coiled drum) to run his wallpaper steamer, but didn't bother to pull all the cord out of the drum. He tripped the MCB on that circuit, eventually, and when I checked the extension lead the drum was dripping with molten PVC insulation.  The heat inside the drum was sufficient to melt it.

Mickey666

GDB2222 said:

Mickey666 said:

TheProfessional said:

That's true. I don't know if it would feel worth it if everything is working well though. I wonder whether £3k now is better than £3k in a decade. If the wires are 25 years old and they could I suppose go on another 10 years or they could fail earlier than that

With a modern CU (ie RCD etc), what's the actual danger of failing wiring?  Obviously there will be nuisance tripping and perhaps even a permanent inability to use a particular circuit, but would there be any actual danger to life or property?

I ask, because if there is no danger to life or property, what would be the point of rewiring if the installation can still pass an ECIR even though the wiring is old?

It can be a fire risk as well as an electrocution risk. It's possible a junction could overheat without tripping an RCD, for example?  I'm sure that @Risteard has a better idea.

I had a painter working in my house. He borrowed my extension lead (on a coiled drum) to run his wallpaper steamer, but didn't bother to pull all the cord out of the drum. He tripped the MCB on that circuit, eventually, and when I checked the extension lead the drum was dripping with molten PVC insulation.  The heat inside the drum was sufficient to melt it.

But why would a junction suddenly start overheating just because of failing insulation?   If it meant conductors touched then that would surely cause the MCB or RCD to trip (depending on the fault)?

I take your point about the danger of cable reels when not fully extended - that's a well known hazard - but it's hardly applicable to fixed wiring is it?

macman

Kitchen light switch-no way should there be a metal switchplate on an unearthed lighting circuit, as your 'vibrating' fingers have already told you. You can change that yourself for a plastic one in about ten minutes, until such time as it's earthed.

TheProfessional

macman said:

Kitchen light switch-no way should there be a metal switchplate on an unearthed lighting circuit, as your 'vibrating' fingers have already told you. You can change that yourself for a plastic one in about ten minutes, until such time as it's earthed.

I did ask if there is a chance I would get electrocuted but he didn't seem to think that very likely! Annoying as every morning when I carry my toddler downstairs it's his job to turn on every lightswitch. I'm glad I asked about it as I actually thought the vibration was because it is next to the fridge!

Risteard

GDB2222 said:

Mickey666 said:

TheProfessional said:

That's true. I don't know if it would feel worth it if everything is working well though. I wonder whether £3k now is better than £3k in a decade. If the wires are 25 years old and they could I suppose go on another 10 years or they could fail earlier than that

With a modern CU (ie RCD etc), what's the actual danger of failing wiring?  Obviously there will be nuisance tripping and perhaps even a permanent inability to use a particular circuit, but would there be any actual danger to life or property?

I ask, because if there is no danger to life or property, what would be the point of rewiring if the installation can still pass an ECIR even though the wiring is old?

It can be a fire risk as well as an electrocution risk. It's possible a junction could overheat without tripping an RCD, for example?  I'm sure that @Risteard has a better idea.

I had a painter working in my house. He borrowed my extension lead (on a coiled drum) to run his wallpaper steamer, but didn't bother to pull all the cord out of the drum. He tripped the MCB on that circuit, eventually, and when I checked the extension lead the drum was dripping with molten PVC insulation.  The heat inside the drum was sufficient to melt it.

Life-expired wiring can indeed be a fire hazard, especially old VIR (Vulcanised India Rubber) cables where the sheath crumbles away when touched. It is a myth that PVC wiring lasts forever - typically manufacturers will state a lifespan of 20-25 years. The more load it carries during its life the quicker it will degrade. If there are VIR cables present any sane Electrician will insist on rewiring them.

RCDs have a failure rate of approximately 7% (or certainly that used to be the accepted figure), and lack of periodic testing with the test button can increase failure of these. It is certainly possible that wiring can degrade dangerously without operating these devices as they rely upon an imbalance through the magnetic coil to operate the trip mechanism. Therefore a fault between live conductors and not to the circuit protective conductor (cpc) will not cause an RCD to operate.

Risteard

Mickey666 said:

GDB2222 said:

Mickey666 said:

TheProfessional said:

That's true. I don't know if it would feel worth it if everything is working well though. I wonder whether £3k now is better than £3k in a decade. If the wires are 25 years old and they could I suppose go on another 10 years or they could fail earlier than that

With a modern CU (ie RCD etc), what's the actual danger of failing wiring?  Obviously there will be nuisance tripping and perhaps even a permanent inability to use a particular circuit, but would there be any actual danger to life or property?

I ask, because if there is no danger to life or property, what would be the point of rewiring if the installation can still pass an ECIR even though the wiring is old?

It can be a fire risk as well as an electrocution risk. It's possible a junction could overheat without tripping an RCD, for example?  I'm sure that @Risteard has a better idea.

I had a painter working in my house. He borrowed my extension lead (on a coiled drum) to run his wallpaper steamer, but didn't bother to pull all the cord out of the drum. He tripped the MCB on that circuit, eventually, and when I checked the extension lead the drum was dripping with molten PVC insulation.  The heat inside the drum was sufficient to melt it.

But why would a junction suddenly start overheating just because of failing insulation?   If it meant conductors touched then that would surely cause the MCB or RCD to trip (depending on the fault)?

I take your point about the danger of cable reels when not fully extended - that's a well known hazard - but it's hardly applicable to fixed wiring is it?

The failure may not cause a fault of negligible impedance as the conductors may not actually be touching, and so protective devices will not necessarily operate. It's why inspection is the most important element of inspection and testing. The testing is merely to supplement the inspection. Plenty of horrors can be observed but not be detected by test instruments.

Mickey666

I'm still struggling to understand a fault mode that would lead to a fire hazard.  I understand old rubber wiring can crumble leading to bare wires, I've had that in my own house, in conduit and the MCB kept tripping when I walked across a floor.  Floorboard moved the conduit slightly, touched a bare wire, MCB tripped.

I get your point about a resistive fault of some kind leading to local heating, but what sort of fault could that be?  Surely not just insulation failing?  It doesn;t start to be come conductive does it, so worst case would be bare wires and if they touch, the MCB/RCD trips.  I understand that an MCB/RCD could fail, but that's a completely different fault.

Also, when it comes to visual inspections, in practice what percentage of the wiring can actually be inspected anyway, or is it deemed acceptable to just inspect the visible wiring behind sockets and switches etc?

Not saying you're wrong, just trying to understand the theory and practice.

Risteard

Mickey666 said:

I'm still struggling to understand a fault mode that would lead to a fire hazard.  I understand old rubber wiring can crumble leading to bare wires, I've had that in my own house, in conduit and the MCB kept tripping when I walked across a floor.  Floorboard moved the conduit slightly, touched a bare wire, MCB tripped.

I get your point about a resistive fault of some kind leading to local heating, but what sort of fault could that be?  Surely not just insulation failing?  It doesn;t start to be come conductive does it, so worst case would be bare wires and if they touch, the MCB/RCD trips.  I understand that an MCB/RCD could fail, but that's a completely different fault.

Also, when it comes to visual inspections, in practice what percentage of the wiring can actually be inspected anyway, or is it deemed acceptable to just inspect the visible wiring behind sockets and switches etc?

Not saying you're wrong, just trying to understand the theory and practice.

They don't need to be touching for current to flow. If they are touching (i.e. a fault of negligible impedance) then even more current will flow, hopefully operating the protective device. Protective devices are selected based on presumed faults of negligible impedance, though in reality this may not always be the case.

Another potential fire hazard are loose connections, which will result in arcing and excess heat. As this gets worse the resistance increases and the problem is exacerbated.

Periodic inspection and maintenance are critical for maintaining a safe electrical installation.

Sample percentages for an inspection will be agreed in advance, and might typically be something like 20% of accessories to be inspected internally. If the sample found faults then the sample size may be increased, even up to 100% where neccessary. Concealed wiring obviously cannot be visually inspected, so it's important to understand that periodic inspection and testing has its limitations. Initial verification is the only time the job can be inspected and tested in its entirety before being put into service.