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Discussion Starter #1 (Edited)
Hello all. I wanted to post about an incident that occurred earlier this week which ended in a severe electrical fire, as I know most of us have some sort of car charging solution at home and want to raise awareness.

To give some background, we had a BMW i3 for around 8 months, and recently changed to a Tesla Model S about a month or so ago. Not long after we got the i3, I installed a 32a Ceeform socket, isolator and new MCB to our existing consumer unit, which was a 'relatively' modern Hager split RCD unit, i.e. all circuits except the lighting protected by a 30mA RCD.
We then bought an Ohme charger with Commando plug through Octopus, which was screwed to the wall inside the garage. All has been absolutely fine, with charging most nights since that time (although not so much through the lockdown period). I should mention now that I am not an electrician, although I trained in electrical engineering and have worked for many years using and repairing high current electrical devices, carried out previous electrical work at home, and felt completely comfortable adding an additional circuit to the consumer unit.

We were woken at about 4am on Monday morning by the sound of a sharp, loud tap tap tap noise. We first thought it was just birds or cats up on the tiled roof, but then we started to smell electrical burning. I immediately rushed down to the attached garage where the consumer unit is, to turn off the power.
I was greeted with the sight of the garage half full of smoke, the consumer unit on fire with flames licking up to the ceiling above, and the most intense noise of electrical arcing, buzzing and sparking. It was a really horrific sight and I could hardly even believe that what I was seeing was actually happening - very surreal.
To cut a long story short, I managed to get outside to the electricity meter cupboard and pull the main fuse to stop the electrical burning. This in itself was quite difficult due to the wire security seals on the fuse carrier. As soon as I pulled the fuse out, the security seals pulled it back in. Thankfully I managed to find a screwdriver and prise it out to break the seals, I then went back inside and threw a container of water over the consumer unit to extinguish the flames, and found the garden hose which thankfully was stored in the garage and doused everything down.
Shortly afterwards the fire service and ambulance arrived as well as the power company, they made sure everything was safe. The emergency crews were absolutely fantastic and arrived very quickly.

Thankfully we are safe including the dog, and the damage was limited to the garage. The fire chief said I did everything absolutely as I should under the circumstances, and he was very surprised I had been able to tackle it successfully.

Now, the obvious question is why did it happen? The logical conclusion is that it was due to the electric car charging, which charges at 32 Amps for up to 4 hours overnight from 12:30 to 04:30. This is the only significant power draw through the night. As I fitted the charger myself over 6 months ago my first thought was 'what on earth did I do wrong?'. I was so certain I had done everything right, and being always paranoid about loose terminals I had quadruple checked all this at the time and was 100% certain everything I had installed was correct, so could not understand how such a thing could have happened.
After a post-mortem on the remains of the consumer unit and wiring, and examination by 2 electricians, it is clear that the wiring from all of the circuits in the house (including the charger) were completely tight and secure, but the main isolator switch at the incoming supply cables from the meter had completely melted away. We concluded a loose, corroded, or damaged terminal at the mains incoming supply, which could have been that way for years. The extra power drawn from the charger over a long duration would have been the 'straw that broke the camels back'.

In hindsight, an electrical inspection should have highlighted this weakness, if we had had such an inspection. They are mandatory on rental properties, but I don't think most of us necessarily think to get one on their own house unless anything looks particularly suspect. I didn't, but do now.

After speaking to our electrician he explained that regulations specify that new consumer units now have to be made of metal for this exact reason, and the incoming tails from the meter have to be enclosed in metal conduit with the terminals torqued down to a specific setting. These regulations do not have to be applied retrospectively to existing installations, but I would say that this experience strongly highlights that this type of failure can and does happen, and would be worthwhile upgrading to the new specification (obviously the replacement unit we have will be to the new regs anyway).
One reason for implementing these regulations he told me, was that with meter replacements being commonplace with the advent of Smart Meters is that any extra tension put on the tails during the meter replacement process can pull on the input terminals to the consumer unit thus exacerbating any pre-existing connection issues. I don't think that was the case here as the tail are fairly long and well secured to the wall, but worth noting.

In addition, he has told me that one of his colleagues mentioned that Teslas are renowned for high AC inrush currents when the charging process starts, and that cabling and overcurrent protection should be rated at 50A for Tesla chargers. If this is true, it could have been the relatively recent change to the Tesla that has put extra strain on the incoming connections. Incidentally I had to switch the power off to a lighting circuit only a few days previous to change a light fitting - there was absolutely no sign of discolouration, plastic distortion, or smell of burning that would have indicated an ongoing issue over a prolonged period. However, this could have been present and hidden inside the consumer unit.

I'm sure some of you are thinking what sort of fool would install his own car charging point? Well hindsight is a wonderful thing, and this experience has taught me that even if you are certain your own work is carried out correctly, every other potential weak point in the system has to be checked. Whether it was a loose screw in the mains incoming terminals, or even a faulty main switch, we will never know. I didn't touch the main incoming terminals but these should have been checked. I know other people have installed their own EVSEs, or building their own DIY EVSEs, and I don't think that this is necessarily a bad thing but want to highlight the potential dangers and things to double-check.

The incident has highlighted a few safety precautions we should take, that most of us already will know and heard many times previously but sometimes these things never get put into practice for whatever reason. We never think this will happen to us. So there are a list of things to address now, which we are doing immediately:

Smoke detectors - there are mains interlinked alarms in the downstairs hallway and upstairs landing. These never went off until I'd already tackled the fire and put it out. A smoke detector in the garage (or wherever the consumer unit is) is now in my opinion essential, this would have alerted us much sooner. The fire door into the garage stopped the smoke coming into the house so did its job. The fire chief also suggested a detector in the loft, as there are usually electrical cables running through there in most houses, and of course usually a stockpile of cardboard boxes full of more junk. We will be having the existing smoke detectors replaced with RF linked units and extra ones fitted in the garage, loft, and kitchen.

Torches - we have torches in various places around the house but they are never where you KNOW they are, and easily accessible in the dark. It was a real struggle in the dark and with the smoke, luckily the streetlights outside gave some light through the windows, but it made it much harder that it could have been. A wall mounted emergency torch would have been a massive help. We will be installing one upstairs and downstairs.

Fire extinguisher - no fire extinguisher will put out an electrical fire until you eleminate the source of the power, but molten plastic had dropped down from the melted board and could easily have caused the fire to spread. The garage was full of the usual crap people store there, including piles of cardboard packing boxes, wood, and all sorts. Without the garden hose being handy, or luckily finding a container I could fill with water at the kitchen sink it could have been much worse. We will be locating a CO2 extinguisher both upstairs and downstairs.

Emergency mains light - the electrician we had in afterwards to quote for repair suggested installing an emergency light near the consumer unit, so if the power fails we have light. This is a given in commercial buildings, and we absolutely are having one installed in the garage now. It was only from the light of the streetlights outside after I opened the garage door that I could see anything at all.

On the plus side, the fireblock plasterboard on the garage ceiling prevented the fire from spreading into the roof space. This really did prevent the entire house becoming ablaze. All the mains cables are melted up to the entry point in the ceiling and completely intact above, which thankfully makes a repair relatively simple.

So I hope others can learn from this experience and at least think about various precautions in case the worst happens. Please if you don't already, make sure you have sufficient smoke detectors in your house if nothing else. I've attached a couple of photos so you can see the extent of the damage.

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Good job you woke up in time and no-one was hurt.

Just goes to show (as you’ve stated) you really need your whole electrical system checked over when you’re putting in an EVSE.

Probably worth a smoke alarm next to the consumer unit or charger for good measure. They aren’t expensive.

Thanks for the warning!
 

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Damn, that's nasty, glad you and yours are all safe. I assume your garage is attached to your house, not detached?

I wonder whether an inspection with an IR camera would have revealed this issue before it became critical?
 

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All that lovely friendly energy that can propel us along on the Motorway at great speed can do terrible harm when unleashed in the wrong place and manner; I'm so relieved you and yours are unharmed.....
The tale of that fire is a lesson for us all.
Deb.
 

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Discussion Starter #5
HI Edd yes the garage is attached, our bedroom and en-suite is directly above. If we had been at the other end of the house in another bedroom (which we were for a while previously during some decorating work), we would not have heard the noise at all. Scary thought.
You know, I also has the same thought afterwards that a thermal imaging camera would potentially identify an issue like this.
 

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HI Edd yes the garage is attached, our bedroom and en-suite is directly above. If we had been at the other end of the house in another bedroom (which we were for a while previously during some decorating work), we would not have heard the noise at all. Scary thought.
You know, I also has the same thought afterwards that a thermal imaging camera would potentially identify an issue like this.
Glad you are all OK including the dog 🐕 I thought two years ago that having 8 smoke alarms and a heat alarm in the kitchen was over doing it but reading your incident makes me pleased, the wiring standards in ireland are different to the UK as I got a steel fuse box but with over 35 different circuits and breakers in my house not only was it not required but was also impossible to source. Like i said glad everyone is and was safe
 

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OMG! Glad you all okay.

Having read this I'm glad I got the guy installing the commando for us (NICEIC electrician) to also supply/fit 3x mains smokes with interlinks and do checks on incoming board. Agree this is something everyone should do as a safety measure, and is a reason you may not want one of the big boys like podpoint to install without also getting a electrician in to check things.
 

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Wow, glad everyone is safe. Thank you for writing this cautionary tale, I'm thinking to get an EICR done now.

I managed to get outside to the electricity meter cupboard and pull the main fuse to stop the electrical burning.
May I ask where might one find this? This is the 100 amp fuse inside the house next to the meter, or some other external fuse we, as residents, can access?

In my house, the house master fuse is right next to the consumer unit, meter and additional RCD for EV charger. In similar situation, it would be difficult for me reaching the house master fuse.
 

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Technical moral of the story is don't put car charging circuit through any consumer unit, make sure is has its own independent supply and protection back to the meter.

An RCD at the meter supply, 300 or 100mA S type, for fire protection, would almost certainly have prevented the fire.

An isolation switch downstream of the meter, upstream of any consumer unit would have been most helpful.

Thanks to the OP for this post.
 

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OMG! Glad you all okay.

Having read this I'm glad I got the guy installing the commando for us (NICEIC electrician) to also supply/fit 3x mains smokes with interlinks and do checks on incoming board. Agree this is something everyone should do as a safety measure, and is a reason you may not want one of the big boys like podpoint to install without also getting a electrician in to check things.
Absolutely 2nd this recommendation.
 

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I think there is (or was) a flaw in the fire regulations because previously I had a similar set-up (I guess it's the same in most houses) with hardwired interlinked smoke alarms in the house in the hall and landing, and a built-in garage with no fire detection at all, so you would only know there was fire in the garage when it had burnt through the ceiling or the fire-door. Yet a basic hardwired, interlinked heat alarm is only around £15, they really ought to be mandatory (if not already) for the house builders to fit them in the garage, just as they have to fit smoke alarms in the hall and landing - the cabling even runs through the garage in many homes because that's typically where the consumer unit is located.

The consumer unit manufacturers bear some responsibility for these kind of over-heatings faults - if you look at an old Wylex fuseboard from say 30-40 years ago, every live and neutral conductor was held by two screws, so for it to come loose and to get a bad joint needed both to lose tension, very very unlikely. With the current designs, safety relies on the tension in a single screw clamp, it's asking for trouble when clamping cables with large cross-sections and where individual strands are large.
 

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Discussion Starter #12
May I ask where might one find this? This is the 100 amp fuse inside the house next to the meter, or some other external fuse we, as residents, can access?
Yes the 100 amp fuse next to the meter. On this house it's in a meter box on the outside wall close to the other side of the consumer unit, but I've had houses in the past where everything is located together and the fuse is underneath the consumer unit. In those cases it would not have been possible to remove it.
It was hard to remove, and required a tool. A main isolation switch here would make it more feasible to turn off the power in case of a similar situation. Or, some mechanical means to eject the fuse carrier to isolate the supply in an emergency.
As it is, there is a vulnerable section between the output of the meter and the input to the consumer unit that is unprotected.
We could see that the remains of the tails into the consumer unit stop around 150mm short of the original location of the main isolator in the consumer unit. The insulation had melted from the tails and as they are clipped together as a pair of Live and Neutral conductors, they had been arcing together and vaporising the copper working its way down the cables.

Here is a picture of the meter box outside with the 100a fuse removed, and a 'before' shot of the installation that I took after fitting the 32a outlet (note that the A4 paper with the circuit designations was added by the previous owner, and I removed it - again, another fire hazard one might not necessarily think of):

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Discussion Starter #13
I think there is (or was) a flaw in the fire regulations because previously I had a similar set-up (I guess it's the same in most houses) with hardwired interlinked smoke alarms in the house in the hall and landing, and a built-in garage with no fire detection at all, so you would only know there was fire in the garage when it had burnt through the ceiling or the fire-door.
I completely agree.
 

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Thankfully you are all safe and you manage'd to save the house. It's all food for thought when using an EVSE at other people's houses and the potential consequences with unknown wiring. As you found out at your cost, you don't need much resistance on a joint to cause a lot of heat when you are taking 32A and once it gets hot the resistance generally increases.

We routinely check our distribution boards at work with a thermal imaging camera, the images are checked against the previous images to see if there are any changes. Last year it picked up a 200A 3 phase breaker that was getting hot on one of the phases due to a slightly lose connector. When we were able to remove the breaker it was in a very sorry state, with charred plastic. The chrome plating on the conductor had all but gone due to heat.
 

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I'm glad everyone is ok. I have a Rolec and frankly I'm waiting for that to burn itself to a cinder. There is a flip switch on the consumer unit inside the house so it's easy to turn off if it does melt.

I think I may be borrowing a thermal imager at some point to see if any of the consumer unit is getting hot or if the Rolec is.

It's always in the back of my mind when I charge over night that there could be the doomsday scenario.
 

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Wow that was a major 💩 alert moment glad your all ok and it reminds me to get our electricals checked I meant to get it done when we moved in nearly 15 years ago but yeah I didn't!!

I did however sort out all the loose connections in the consumer unit in our outbuilding when I fitted some lights, wasn't surprised to see evidence of a previous fire when I was doing that!
 

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Discussion Starter #19
I think that's going to be the worry from now on, that the charging happens overnight when we are asleep. I'd been trying to get on the 'Go Faster' tariff anyway so we could start charging at 8.30pm instead of in the middle of the night on Go, but Octopus seem to be ignoring me.

Either way, I'm now going to take some time to think of the best way to move forward with home charging. I've told the electrician to forget putting a 32a socket in for now, and we'll charge at the local Supercharger for the short term (3 miles away) when needed. Need to reflect on the best option going forward, and make the right choice on the charging unit and installer. Not that there was anything wrong with the Ohme, but the whole incident feels a little raw right now.
 
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