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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.
![133817]()
![133818]()
![133819]()
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.
