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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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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...
Is there a non-invasive way to tell when the breaker needs replacing? Use an IR thermometer to take its temp?
 

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Is there a non-invasive way to tell when the breaker needs replacing? Use an IR thermometer to take its temp?
The breakers are more robust now than ever before. The CH breakers in my house and the ones in the sub panel for my garage/EVSE project are actually service rated, in that you can use them like an on/off switch where it was not allowed and quite frankly frowned upon to do so in the old days. It's not uncommon for a breaker to be warm to the touch, but that is all it should be. I used one full gauge of wire better than required in my EVSE project and I was still surprised that the wires going to my EVSE were slightly warm. That's loss of efficiency and I was trying to avoid that 100%. I myself have never experienced a breaker wearing out. But my oldest breakers in my world were 30 years old. Now, sea air or other factors that would cause corrosion is really a different issue, not so much the breaker wearing out as much as the elements getting the best of it.
 

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Good to hear, my current plan is adding 50A breaker and use #6 wire to make a NEMA 14-50 receptacle. Then, use outlet adapter to let me hook up my OEM EVSE, which would draw at max 12A. I would expect the breaker to be only slightly warm, if any.
 

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Good to hear, my current plan is adding 50A breaker and use #6 wire to make a NEMA 14-50 receptacle. Then, use outlet adapter to let me hook up my OEM EVSE, which would draw at max 12A. I would expect the breaker to be only slightly warm, if any.
The JuiceBox 40 Pro wire in the cable and specifically in the pigtail is 8AWG. I ran 6AWG to that. Here is a picture of the temp of the 6AWG wire 1 hour into a charge of my Bolt. So, figure that wire is taking 31 amps realistically. Or 32, not worth debating.

Granted, the IR thermometer is not exactly scientific but it was showing the surrounding air/environment/surfaces at 72 degrees which was accurate. Moving over the load carrying conductors showed a 17 degree increase. Again, 31-32 amps on 6AWG. There was no other load active in that load center so no heat was carrying from other wires and the cover was OFF the entire time so no heat build up in the cabinet. The surrounding wires were room temp., this load center really exists just for the car and serves as a disconnect if I go above 60 amps. Prior to this, I personally would not have guessed that 6AWG THHN wire, new wire, the THHN2 to be specific, would ever be 'warm' at 31-32 amps. My project used 75 degree C ratings per code, because circuit breakers are rated at 75 degree's C, not 90 which is what most amperage charts will lend you to rate wire for.

20190505_205725_resized.jpg
 

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Good to hear, my current plan is adding 50A breaker and use #6 wire to make a NEMA 14-50 receptacle.
Exactly what I did. It's future-proof, costs very little extra, and there is not going to be any undue warming, especially with a 32A vehicle.
Then, use outlet adapter to let me hook up my OEM EVSE, which would draw at max 12A. I would expect the breaker to be only slightly warm, if any.
I got a JuiceBox 40A, also on the theory that by undertaxing the hardware it should last forever. But truthfully, with my use pattern I could have gotten away fine with the OEM EVSE trick. (I have heard, however, that these small units are prone to failure, even without being taxed at 240/12.)
 

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I'm all for self repair. That said, turn the main breaker off when servicing the 50a breaker. Don't rely on tape and a steady hand to keep you from a shock...
Definitely! I did that when wiring my new 50A breaker and did not wear gloves.
And when it was all done and tested, I realized I'd not thrown the disconnect on the solar array! :eek:
 

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Definitely! I did that when wiring my new 50A breaker and did not wear gloves.
And when it was all done and tested, I realized I'd not thrown the disconnect on the solar array! :eek:
I intentionally did my install with the live panel so that my wife wouldn't know what I was doing. She noticed the EVSE plugged in to the new 240 outlet a few days later. At that point, I just had to ask for forgiveness.
 

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I intentionally did my install with the live panel so that my wife wouldn't know what I was doing. She noticed the EVSE plugged in to the new 240 outlet a few days later. At that point, I just had to ask for forgiveness.
I worked on mine live as well. If you take precautions, wear the right clothing and have an IQ over 90 it's ok. To each his own.
 

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I may get a faster EVSE right before taking a long trip or buying a 2nd EV. No need for speed at this time. Daily recharging on 240V 12A is 2x of my needs right now.
 

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The breakers are more robust now than ever before. The CH breakers in my house and the ones in the sub panel for my garage/EVSE project are actually service rated, in that you can use them like an on/off switch where it was not allowed and quite frankly frowned upon to do so in the old days. It's not uncommon for a breaker to be warm to the touch, but that is all it should be. I used one full gauge of wire better than required in my EVSE project and I was still surprised that the wires going to my EVSE were slightly warm. That's loss of efficiency and I was trying to avoid that 100%. I myself have never experienced a breaker wearing out. But my oldest breakers in my world were 30 years old. Now, sea air or other factors that would cause corrosion is really a different issue, not so much the breaker wearing out as much as the elements getting the best of it.
Yeah. I probably should have mentioned that I live less than a mile from the Pacific Ocean.
 
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