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Hi, all:

Newbie here - new to the Forum, new to EVs, new to the Bolt, and new to my new AV TurboDX 32A home charging station just installed today and using for the first time tonight to charge my Bolt from 63% battery to 100%.

I've noticed the following: The wall charger unit is warm (blue light blinking slowly, as expected). The cable from the unit to the charge port is warm. The Bolt itself in the vicinity of the chargeport is warm. From the charging stats, it seems the car pulled around 25 to 30 amps at the beginning, but has slowed down as it reaches full charge. Some fan inside the car cycles on and off slowly - otherwise, no odd noise. No unusual notices from the car display. Charge time is around 3-3/4 hours which seems about right. All of this seems normal as far as I can tell.

My question for the more experienced here is that the 40A breaker (on an unused 50A circuit for an electric range in a 200A panel) is almost too hot to touch. I don't know what the temperature is, but I can't lay my palm across the exposed face of the breaker plastic body for more than 10 secs without it being too uncomfortable to continue. There is no hot or burning smell - no vibration or buzz. It is just hot.

Is this normal? The breaker temperature has not increased while I've been watching it tonight. If anything, the temps seems to be moderating a bit as the car pulls less and less current toward full.

Thanks for any advice you can all provide. Just looking to know if I need to call the electrician back out.

PS: If this question has already been answered, feel free to direct me to the right discussion.

PPS: What a great car! It is like the diff between a rotary phone and a smartphone. Not likely to buy a gasoline car ever again.
That is definitely not normal. What size wire is on the breaker? If it's #6 upgrade the breaker to 50 amps and should fix the problem. If wire is #8 then I'd check the screws on the breakers to be sure they're tight, if they are then replace it with another 40amp breaker because for whatever reason it's getting hot and not tripping is a fire hazard. Now some warmth is normal, but where you can fry an egg on it is not normal.
 

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I have a Juicebox Pro 40 on a 30 Amp breaker. Normally I limit output to 24 Amps to comply with the 80% rule. Sometimes, though, I'm in a pinch for all the electrons I can get owing to a late night return and need a full charge early, or a short home stop before moving on. (I drive 150-250 miles / day)

On those occasions I'll bump the JB to full tilt boogie (33 amps; the car takes 31.7 max). Of course that represents a moderate overload of the 30 Amp circuit. Breaker and cable are new; run is short. Breaker and cable get slightly warm to the touch.

Of course don't try this at home...always comply with the 80% rule for long duration continuous loads. That said, I present this info to point out that a properly installed 40A circuit shouldn't be more than ever so slightly warm when operating at 32 amps.

NOTHING in an electrical system should EVER be anywhere near too hot to touch!

Advice to replace breaker and occasionally tighten everything in a panel box is spot on. In the course of replacing breaker examine panel bus bar for signs of heating / arcing damage.

I second the notion that working in a hot panel is not for the faint of heart - been there, done that with similarly illuminating experiences.

If any of this is unfamiliar or scary, back off and call a pro...downside risk is simply too high - lethal voltage and current lurk within awaiting the unwary and ill-informed.

If possible, future proof the circuit to 60 amps, allowing 48 amps / 11+ kW for next gen EVs
 

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Discussion Starter #23
Update: I drained the car to less than half-full (Isn't Sport mode fun??), then had the electrician back to inspect the charger installation work. The guy who came back out was the original electrician who quoted the work - it was actually installed by his colleague and an apprentice. These guys work for the same company that installed the chargers at the dealer where I bought the Bolt and who recommended them. They seem to do quite a bit of industrial work with some residential. They come in a clean lettered van and have all the equipment. They seem confident, working on the hot panel with gloves and goggles without cutting any of the electricity to the house. Point being: The guy does this for a living.

He inspected the installation, re-torqued the connection points to the breaker, and also moved the AC breaker across from the charger circuit down one slot (swapping with the 20A 110V breakers that were below). He let everything heat up and verified that the circuit was feeding 32A to the charger at 240V. With IR, he showed me the contact temp at the back of the breaker to the wires was 150 degF. (ambient maybe 80-85). The temp on the plastic face of the breaker was noticeably warm, but not as hot as before. I could leave my palm against it without discomfort - quite warm but not hot. (A few days later, I ran another charge cycle - same result.)

He did not think there was anything out of the ordinary and was pretty non-chalant about the temps. He did not see anything wrong with the breaker externally (no distortion or evidence of overheating) and did not think it needed to be replaced.

So there you have it. For what its worth, the cord in the charge unit (on the other side of the garage from the panel) is also warm(ish) when charging.

This whole EV experience is pretty interesting. We took our first longer trip last weekend (about 150 miles RT) returning with slightly less than half the battery left. The car is so quiet - we actually had a conversation! We took the backroads (state highways) instead of the interstate so that helped. Although the drive took about 20 mins longer one-way, both of us felt much less tired when we arrived there and when we came back. Driving the car is really a great user experience.

And the technology is eye-opening in comparison to gas: On household power, you can put 7kW into the car taking 10 hours to fill from empty. Gasoline is a miracle compound, really - in 5 minutes you can put 20 gallons in the car with 600 kWh equivalent going into the tank. That's a whale of a lot of energy, either way - by comparison,1 kg of TNT holds about 1 kWh. (Of course, that 1 kWh in TNT all comes out in a millesecond...) Gasoline holds so much energy, we have grown accustomed to being wasteful - I used 33kWh to go 150 miles as opposed to burning 180kWh of gas in our other car. Good thing gas is pretty stable as a liquid.

I suppose that as EVs become more commonplace, there are going to be houses burnt down from overloaded circuits just like there were probably barns burnt down in the first generation of horseless carriages a century ago. Interesting times! Porsche's 900V chargers can't come fast enough.
 

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He let everything heat up and verified that the circuit was feeding 32A to the charger at 240V. With IR, he showed me the contact temp at the back of the breaker to the wires was 150 degF. (ambient maybe 80-85). The temp on the plastic face of the breaker was noticeably warm, but not as hot as before.
I'm no electrician and I believe the temps you are reporting are within specification but in all honesty it seems warmer than I expected them to be. I once posted IR temps for cable warmth, way lower than yours but primarily because my wire gauge is different. I just remember reading after I installed my 22kW Generac generator by myself that wires heating up are normal but it is loss of $ and efficiency and whenever possible the rule of thumb was to use a wire gauge one better than the instructions/NFPA/code calls for.

I would like to check mine at my next charge which should be Wednesday. How many minutes was the system delivering power to the car when he IR tested the wires and saw 150 degrees? I'd like to test at the same point.
 

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There’s a difference in design and testing specs and what is normal. Breakers should remain very close to room temperature in operation. They are designed to work at elevated temperatures as a safety measure so they don’t cause a fire, but a warm or hot breaker used in a circuit it’s designed for needs replacing.
 

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Breakers do wear out over time. I've got a 240V 40A breaker that feeds an EV charging circuit that's been in steady use since 1997. I've replaced it twice, and both times the internal contacts were corroded. Electrons don't flow through corrosion very well...
 

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Get a spare breaker, swap it out with the existing breaker, and see what kind of temperature it rises to while charging your car under the same conditions. If it stays much cooler then keep the new breaker and throw out the old one.
 
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