[CZroe]

But it probably wouldn't have caught fire if it wasn't pulling 50+ amps. One of the responses suggested that as much as 100A over 30-60 seconds could be flowing before the 50A breaker trips (and as a recap, the 50A breaker did trip).

Actually, to correct myself, it would be around a minute or so at 65A for a thermal trip and near instantly for a magnetic trip (dead short or 100A).

 

[enslay]

Right... but you seem to be assuming that the fire happened because it was drawing too many amps. A) There's no evidence of that and B) why would it do that? It is WAY more likely, as I said before, that it was a damaged wire/connection that caused it to overheat -- not a high amp draw. And it would have done that on 120v or 240v.

Look at the condition of the unburnt part of the cable. That thing was not taken care of.

It would happen instantly as soon as there is a dead short which lends credence to the idea that there was high resistance in the cable due to damage… likely frayed wires that were still insulated until they melted. Frayed wire would do the same once enough strands break even if were originally rated for 50A and on a 50A circuit.

Look, it doesn't matter how it happened or whether it could have happened on a 120V 15A circuit. What matters is that it reached a point where it tripped a 50A breaker and that's really dangerous for the wiring used in the EVSE which wasn't designed for that amperage.

This is not meant to be opposition to your practices. It's the kind of example of "something bad happening" I've been mentioning where the EVSE is able to pull more amperage than it was designed for. And a very simple safety fix is to use an appropriately sized breaker (15A) or to put a fuse on the adapter.

 

[CZroe]

Look, it doesn't matter how it happened or whether it could have happened on a 120V 15A circuit. What matters is that it reached a point where it tripped a 50A breaker and that's really dangerous for the wiring used in the EVSE which wasn't designed for that amperage.

This is not meant to be opposition to your practices. It's the kind of example of "something bad happening" I've been mentioning where the EVSE is able to pull more amperage than it was designed for. And a very simple safety fix is to use an appropriately sized breaker (15A) or to put a fuse on the adapter.

Any breaker will blow with any dead short. A 15A breaker wouldn’t have saved it because it was already damaged beyond reasonable repair. If it allowed them to keep using it until they damaged it enough to melt on a 15A breaker, the result is the same.

Internal strands break and resistance increases causing heat. Heat causes the insulation to melt and then you get a dead short, tripping the breaker instantly. If the extra impedance of the high-resistance frayed cable caused the 15A breaker to trip first, well, it still didn’t save the EVSE.

 

[CZroe]

Look, it doesn't matter how it happened or whether it could have happened on a 120V 15A circuit. What matters is that it reached a point where it tripped a 50A breaker and that's really dangerous for the wiring used in the EVSE which wasn't designed for that amperage.

This is not meant to be opposition to your practices. It's the kind of example of "something bad happening" I've been mentioning where the EVSE is able to pull more amperage than it was designed for. And a very simple safety fix is to use an appropriately sized breaker (15A) or to put a fuse on the adapter.

Also, the wiring to the ClipperCreek Gen2 EVSE J-plug in the stock EVSE was designed for more than 15A.

 

[enslay]

Also, the wiring to the ClipperCreek Gen2 EVSE J-plug was designed for more than 15A.

The 50A ClipperCreek I have has a different (much thicker) wire compared to the Bolt's EVSE. So probably still not designed for 50A.

 

[evtinker]

I think this could be a good argument for adding some sort of inline 15 Amp fuse or breaker to 120 to 240 adapters, which then sounds like sufficient increase in cost and complexity to warrant just buying an actual 240 VAC Level 2 EVSE instead. This is also the kind of picture you show your spouse to justify the purchase.

 

[enslay]

I think this could be a good argument for adding some sort of inline 15 Amp fuse or breaker to 120 to 240 adapters, which then sounds like sufficient increase in cost and complexity to warrant just buying an actual 240 VAC Level 2 EVSE instead. This is also the kind of picture you show your spouse to justify the purchase.

Really? I thought fuses should be cheap.

And why not something like @ga500ev's linked adapter or British travel adapters that have built-in fuses? That can't cost much. (well, somebody has to go and make such a thing).

 

[CZroe]

The 50A ClipperCreek I have has a different (much thicker) wire compared to the Bolt's EVSE. So probably still not designed for 50A.

Right, but it’s that same as the 16A AmazingE and maybe even the 24A AmazingE FAST (I’ll have to check on that one). [Edit: Nope. AmazingE Fast has a MUCH thicker/heavier cord]

The EVSE is supposed to trip on even a tiny short to ground (milliamperes) so it was likely a high impedance fault due to frayed wire. The owner would pack it up and bring it out every single day for charging in the parking lot so it got a lot of wear and tear. I’m glad he was using a quality unit or it wouldn’t have lasted as long as it did. It was amusing to see someone in the Reddit thread recommend that he get something from ClipperCreek to replace it because they are “more robust.”

…

Yeah, if he gets one like yours. He already had one more robust than most cheap EVSEs.

 

[enslay]

Right, but it’s that same as the 16A AmazingE and maybe even the 24A AmazingE FAST (I’ll have to check on that one).

The EVSE is supposed to trip on even a tiny short to ground (milliamperes) so it was likely a high impedance fault due to frayed wire. The owner would pack it up and bring it out every singe day for charging in the parking lot so it got a lot of wear and tear. I’m glad he was using a quality unit or it wouldn’t have lasted as long as it did. It was amusing to see someone recommend that he get something from ClipperCreek to replace it because they are “more robust.”

OK, so then maybe just use it on 30A or less or something like that. Whatever some very knowledgeable tinkerer (like from Volt's forum) determines the safe amperage to be.

 

[CZroe]

I think this could be a good argument for adding some sort of inline 15 Amp fuse or breaker to 120 to 240 adapters, which then sounds like sufficient increase in cost and complexity to warrant just buying an actual 240 VAC Level 2 EVSE instead. This is also the kind of picture you show your spouse to justify the purchase.

I think daily packing/unpacking justifies having more than one to distribute the wear and tear.

OK, so then maybe just use it on 30A or less or something like that. Whatever some very knowledgeable tinkerer (like from Volt's forum) determines the safe amperage to be.

The 16A AmazingE version of the same EVSE comes with a 30A wall plug and the same J1772 cable so ClipperCreek must think it’s safe for a 30A circuit.

 

[evtinker]

The sad part is realizing no matter what this was plugged into, this unit failed at 12 Amps current. That would be all the Bolt's charger would be drawing, even at 240 VAC. This has to be damaged wires, enough to either reduce the number of complete strands so the remaining ones were overloaded, or perhaps even damage the insulation enough to develop a short. The visible damage is more likely effect than cause. Potentially a similar failure could have occurred on 120 VAC, though it probably would have caused less damage. At a minimum this should encourage those who pack and unpack their EVSE for each charge to not wind it up any tighter than necessary.

 

[CZroe]

The sad part is realizing no matter what this was plugged into, this unit failed at 12 Amps current. That would be all the Bolt's charger would be drawing, even at 240 VAC. This has to be damaged wires, enough to either reduce the number of complete strands so the remaining ones were overloaded, or perhaps even damage the insulation enough to develop a short. The visible damage is more likely effect than cause. Potentially a similar failure could have occurred on 120 VAC, though it probably would have caused less damage. At a minimum this should encourage those who pack and unpack their EVSE for each charge to not wind it up any tighter than necessary.

Higher voltages will more readily arc from a greater distance so it’s possible that 240v would arc and trip the breaker ever so slightly sooner as all the insulation breaks down and the exposed wires get close or contact.

As the heat and resistance went up it’s likely that the current momentarily exceeded 12A. Because resistance causes heat and heat further increases resistance, I believe you’d get a quick thermal/current run-away at the very end. I don’t think the EVSE can detect that and shut off since everything was still signaling 12A or less through the J1772 protocol. Once something shorts the breaker or EVSE would’ve cut it off near instantaneously.

 

[D_Spear]

Check this out:
https://www.reddit.com/r/BoltEV/comments/vqj48q
I don't know kind of circuit the author had, but they were running the Bolt's EVSE with a 240V adapter. So I'm guessing a 240V on a > 15amp circuit? The author reports that the circuit breaker did trip, but not until after the handle caught fire. It probably wouldn't have caught fire if it was on a 240V 15amp circuit like with a 6-15 outlet. This is probably a very rare event, but that's why I would prefer to use a 15amp 240V circuit if I adapted the Bolt's L1 EVSE... or alternatively to put a fuse in the adapter to prevent the EVSE from potentially drawing more current than it was designed to draw should it be used on something like a 50amp circuit.

Here's the thread describing all the details.

EDIT:
It was a 50 amp circuit.

From what I can see, this likely happend because of what others have stated, the cord was in poor condition and not taken care of. From what I can see, I suspect that the connection was loose at the soldering or so twisted it actually ruined part of the conductors. A fuse would not have likely not helped here. The increased resistance from a poor connection or too small of wires due to damage, will cause heat in the weakest point of the conductors or fuse ( if it had one), in this case it was the damaged part of the cable.Because the fuse should be sized for the wire, it would take a constant over current or dead short to burn the fuse out, but because the wire was very damaged, the wire at the burnt area is actually smaller now and weaker than the fuse. In a way, the cable acted like the fuse and burnt in half.

 

[enslay]

From what I can see, this likely happend because of what others have stated, the cord was in poor condition and not taken care of. From what I can see, I suspect that the connection was loose at the soldering or so twisted it actually ruined part of the conductors. A fuse would not have likely not helped here. The increased resistance from a poor connection or too small of wires due to damage, will cause heat in the weakest point of the conductors or fuse ( if it had one), in this case it was the damaged part of the cable.Because the fuse should be sized for the wire, it would take a constant over current or dead short to burn the fuse out, but because the wire was very damaged, the wire at the burnt area is actually smaller now and weaker than the fuse. In a way, the cable acted like the fuse and burnt in half.

The fuse would have prevented it from drawing more than 50A (the 50A breaker tripped). That would probably greatly reduce the damage and also the risk of fire. I'm also not the only one saying this.

EDIT: Just a polite reminder, the L1 EVSE's wiring is not rated for 50A... and for a time, it was drawing 50A (something everyone insists doesn't happen). Hence the suggestion to use an appropriately-sized breaker or use a fuse.

 

[jmcbrew]

From what I can see, this likely happend because of what others have stated, the cord was in poor condition and not taken care of.

Exactly. That cord looks like every extension cord that my wife (at home) or an employee (at work) has wound up incorrectly.

 

[D_Spear]

The fuse would have prevented it from drawing more than 50A (the 50A breaker tripped). That would probably greatly reduce the damage and also the risk of fire. I'm also not the only one saying this.

But a fuse is designed to be the weakest point of system, rated for the amperage rating of the wire. When the wire is damaged, and in a way made smaller because of that, the heat is created in that spot, resulting in wire being melted. The weakest point gets damaged first.

 

[enslay]

But a fuse is designed to be the weakest point of system, rated for the amperage rating of the wire. When the wire is damaged, and in a way made smaller because of that, the heat is created in that spot, resulting in wire being melted. The weakest point gets damaged first.

Right. The L1 EVSE's wiring isn't rated for 50A. So put a 15A fuse on the adapter... or use a 15A breaker.

I don't care where it failed. It pulled 50A and tripped the breaker!

 

[D_Spear]

Right. The L1 EVSE's wiring isn't rated for 50A. So put a 15A fuse on the adapter... or use a 15A breaker.

I don't care where it failed. It pulled 50A and tripped the breaker!

It tripped the breaker because of a direct short from phase to phase or phase to neutral/ground. A 15 amp breaker probably would have tripped after the fact. A breakers job is to trip during over current or dead short, it will not notice when a wire is damaged and getting very hot. Just because the wires burnt in half doesn’t mean it was pulling 15 amps…. Electrical fires happen all the time in homes because of loose connections, just like this. Now AFCI breakers, which are becoming code may help.

 

[enslay]

It tripped the breaker because of a direct short from phase to phase or phase to neutral/ground. A 15 amp breaker probably would have tripped after the fact. A breakers job is to trip during over current or dead short, it will not notice when a wire is damaged and getting very hot. Just because the wires burnt in half doesn’t mean it was pulling 15 amps…. Electrical fires happen all the time in homes because of loose connections, just like this. Now AFCI breakers, which are becoming code may help.

I think the wiring insulation probably melted and it shorted and drew more than 50A for a time. What if it somehow shorted and only managed to draw 40A continuous through it's 15A (maybe 30A-rated) wiring? That wouldn't trip the breaker. How would that turn out? It's a good thing it tripped the breaker... it may not have happened that way.

Look, you can do whatever you want. This is just a very rare counterexample of, "Oh, it doesn't draw more than 12A"... only it can if something catastrophically bad happens. And that might lead to a fire. Our neighbors across the pond fuse their plugs because they use high amperage (30A+) circuits for their normal outlets. This is an example of why they do that.

 

[D_Spear]

I think the wiring insulation probably melted and it shorted and drew more than 50A for a time. What if it somehow shorted and only managed to draw 40A continuous through it's 15A (maybe 30A-rated) wiring? That wouldn't trip the breaker. How would that turn out? It's a good thing it tripped the breaker... it may not have happened that way.

Look, you can do whatever you want. This is just a very rare counterexample of, "Oh, it doesn't draw more than 12A"... only it can if something catastrophically bad happens. And that might lead to a fire. Our neighbors across the pond fuse their plugs because they use high amperage (30A+) circuits for their normal outlets. This is an example of why they do that.

The best way I can explain this is electricity wants to get back to the source ASAP, and it will take any path to get back there. In this case when the wires melted, a few things could have happened. Either phase to phase came into contact with each other, if so that would have tripped the breaker EXTREMELY FAST, in fact there is a formula for that. Or a phase melted to neutral or ground, which is exactly what it’s looking for, the fastest way back to the source. When this happens an extreme inrush of amperage happens, and again, the breaker will trip extremely fast. When a short happens, it typically pulls an extreme amount of amerage, which will trip the breaker very fast. In my career, I have never seen a breaker not trip because of a short( unless its a FPE panel). It’s important to note, the charger likely didn’t pull 50 amps, the wire actually did.