HPWC/breaker almost caught fire...thoughts?

[StealthP3D]

Hi, I'm an electrician in the Buffalo, NY area.....

I would, at a minimum, consider going to a slightly more expensive panel, such as Eaton's 'CH Line' (for the old Cutler Hammer), where the stabs are somewhat more substantial and are of copper construction.

Great advice! I have three electrical panels in our two homes and they are all Eaton's "CH" line. They are really nice with the copper bus bar and the breakers themselves seem a little more substantial. I won't buy anything else. A lot of panels are manufactured to the lowest possible price point. The cheap ones generally work fine if the installer pays attention to details but this is not a place to cut corners.

It's more important to have an experienced, non-rushed electrician than the best panel but why take chances? In this case, I suspect wall texture over-spray on the bus bar where the new circuit was added. It's very common for lazy contractors to not mask off the panels before they spray paint or texture but this has killed people. Wall texture and paint are both good insulators. A good electrician will notice this and spend the extra time to rectify the situation but most electricians don't want to spend the time.

 

[Bill25cycle]

Thank you for the kind words, respect.



And thanks everyone for the feedback. Because of your comments and recommendations, I've put in a call to the electrician to have the box replaced. Hopefully we will not encounter any more issues. But I will update everyone.

In the meantime, let me add some additional pieces of information. Sorry, I didn't intend for this thread to be so long winded.

1. Now that I think about it, our house did flood during Hurricane Harvey. I have little faith in the people who did the electrical work as they robbed us. Literally. Disconnected our alarm, left a back window unlocked, returned at night and robbed us.

2. After the little electrical incident, the electrician did notice a very very very light vibration feeling from the wire. I apologize, I cannot recall which gauge wire he used. But he found it extremely strange and said he had never experienced that before.

3. The HPWC is a Gen 2. At the time, Tesla was sold out of the 24ft ones and I found a lightly used one locally. Someone bought a house and the Tesla charger was there and not needed. He didn't own a Tesla. It was in good condition, included plenty of wiring, but again used. The electrician actually recommended a different gauge, I think thicker, but the details slip my mind as it was months ago.

Regarding the wires vibrating, sometimes motors starting 'across-the-line' or sometimes called DOL for, "Dropped on-line" use 6 to 10x the rated running current.

I was at a Church a few years ago that had a 40 hp phase converter... When starting, the unit would draw 400 amperes off of a 100 ampere double pole breaker for the 3 seconds it took to accelerate. The breaker got noisy and felt like it was vibrating itself out of the panel. (The funny thing was this was for an elevator, that by my calculation would blow if you ever loaded it to capacity). The voltage at the service entrance dropped to 180 and some of the fluorescent lights would have to restrike afterwards. The heavy duty 400 ampere service only had a 25 kva transformer feeding the church alone, since the power company didn't want to propagate the starting issue into the neighbor's homes.

(Of course, they also had 2 - 225 ampere feeders in the panel, one of which was to a boiler room panelboard with a grand total of 9 amperes of load tops). I suspect that 100 ampere breaker feeding the phase converter will wear out before its time. If the power company had used anything other than a dinky transformer, the starting current would have been more like 500 amperes and the breaker would nuisance-trip.

 

[JeffnReno]

The properly sized panel, correct breaker for the panel/load, properly gauged wires, clean tight connections, check/double-check/triple- check everything, and don't die in your sleep while your car is charging. Press on breakers are known to loosen when cycling them and always use 2 hands when doing so. One hand keeping the breaker seated firmly against the busbar and the other for switching the breaker. The suggestion about checking the tightness of all your connections every year is a good one too. I've seen connections with burnt wires on neutral bus connections due to a stripped screw that felt tight but wasn't and the wire could actually be pulled right out it was so loose.

 

[Denny_Camp]

The damage is where the high resistance was. Resistance can come from an air gap (not tight) or something physically between the connection. If the wires connected to the breaker were not damaged, then the issue was not with them or how they were connected. Resistance in one area will not transfer damage (heat) to another area. With the way the stabs on the power connection are damaged, there was a connection issue to the bus. Something potentially like one of the two stabs was slightly bent and was jammed between the wall of the breaker and the connection point in the breaker, instead of fully seated in the connection. Something like that would have enough connection to run the charger, but would get hot and cause damage at that connection.

 

[xrayangiodoc]

Amazing. I have been using my HPWC for 6+ years. I got, "Dual Chargers" in my 2014 S85 and routinely charge at 80 Amps. Were the old HPWCs better quality?

 

[mongo]

Amazing. I have been using my HPWC for 6+ years. I got, "Dual Chargers" in my 2014 S85 and routinely charge at 80 Amps. Were the old HPWCs better quality?

The issue at the breaker panel was not due to the Wall Connector (beyond the fact that it was part of a high current load path).

As to differences, the recent Gen 3 WC is limited to 48 A charging (as are recent vehicles).

 

[drtom355]

I am not sure if someone else posted this, I did not read every post. A good electrician would know that your breaker needs to be as close to the main as possible. This very thing happened to my friend and his model S, the new electrician who fixed it moved the breaker to the top of the row in the first position, problem solved. A year later when an electrician came to install my Gen 2 for my Model X he told me he had to move a few breakers so he could install my 60amp at the top to avoid overheating.

 

[mortarotti]

Gen 2 HPWC
2016.5 Tesla S P90DL
48 amp charging/60 amp breaker

Video and pic below


So I say HPWC/breaker, because I'm not sure what the problem was. My electrician came and looked at it and couldn't say definitively either. Likely a bad "breaker" so he replaced it(the breaker) and said I will need a new panel.

Since then, I have installed a smoke/carbon monoxide detector, just to be safe. A few times I could smell something burning, same smell as the time it almost caught fire, so I started charging at 30 amps....with a fire extinguisher handy. Side note, hanging out in the garage, I've gotten a lot of cleaning done. Charging at 30 seemed ok, but the breaker still got warm.

Now, a few weeks later, my car stopped charging. Turns out the breaker was getting hot and causing the HPWC to stop charging, but not tripping the 60 amp breaker. Also caused some adjacent breaks to get hot and trip.

So trying to determine my path forward. Replace breaker again? Or is the HPWC bad? If I let the breaker cool down, reset the breaker, and then reset the HPWC, it works but I'm not comfortable using it.

Thoughts?



Breaker for HPWC was installed at the bottom and you can see how it burnt upward.

View attachment 549080

 

[mortarotti]

I messed up.
Assuming you have the correct wire guage #6 for a 60A breaker, are the breakers new? Was the replacement breaker new, and rated for 60 Amps? The only thought that comes to mind is get a different electrician. Something is drawing more current than the circuit can handle.

 

[robapodaca]

As an electrical engineer, I personally set my Tesla to charge overnight at 60 amps (vs the 80 amps it can handle). I do this to minimize the current flow / heat generation in the electrical panel (where I have a 100 amp breaker), the HPWC charging cord, and especially the end connector that plugs into my 2013 Model S (I am the original owner, coming up on 94k miles).

Also it minimizes the heat generation in my P85 battery pack. Charging overnight, I am in no hurry, so limiting the current flow is OK, and minimizing the heat in my battery while charging will extend the battery pack life.

 

[mongo]

As an electrical engineer, I personally set my Tesla to charge overnight at 60 amps (vs the 80 amps it can handle). I do this to minimize the current flow / heat generation in the electrical panel (where I have a 100 amp breaker), the HPWC charging cord, and especially the end connector that plugs into my 2013 Model S (I am the original owner, coming up on 94k miles).

Also it minimizes the heat generation in my P85 battery pack. Charging overnight, I am in no hurry, so limiting the current flow is OK, and minimizing the heat in my battery while charging will extend the battery pack life.

You say minimizing, but 60 Amps is more that any new production vehicles can charge at...

 

[LoveMX]

Wow, this is scary! I hired a Tesla recommended electrician to install mine back in 2019, not sure what Gen mine is, but I hope the electrician took care so that this type of thing doesn't happen. How do I ensure that mine has been installed correctly? Is an annual maintenance check is required? Really scares me as I have know a colleague whose parent died from a house fire.

 

[animorph]

If it doesn't get hot anywhere along the wires and electrical box/breaker I wouldn't worry. I think the OP install was good, but the electrical panel had deteriorated, perhaps due to the flooding or just age.

 

[Snerruc]

Do you genuinely believe that a breaker or receptacle with a UL approved rating won't at least meet it's designed use as a starting point? The reality is that these items are tested beyond these minimums by Underwriter Laboratories for a specified degree of safety margin. If you think that a UL approved 50A breaker and/or 50A outlet can't sustain 80% of this (40A) and still garner a UL approval then you don't understand what goes into modern electrical application or UL testing & approval. More often than not when a receptacle "fails" it's operator error in terms if improper wire choice, improper connections or both. So many of these posts of bad equipment are operator/installer error but many in the Tesla community think that spending more always guarantees a better result. Even if you use a beefier receptacle you can cause a fire by improperly installing it. Sustained 80% draw just accelerates the failure.

Yes. Industrial parts are tested to more rigorous standards and will basically run at load forever on a line. That $12.00 part at Home Depot. Is not even built to allow frequent insertion. Saw the results of that on an install at a friends. Yes, proper standard duty parts installed properly usually last a long time, but $50 more to use parts designed for continuous duty is a reasonable investment in protecting your perhaps million dollar house.

 

[Carl Brandon]

I had the same problem. One breaker failed (wouldn't stay on) and I replaced it (60A). The second one just failed:

As you can see it burned up. My first thought was that the high resistance was at the clip-busbar interface (the clips are in the bottom of the photo), but when I removed the breaker, the clips stayed behind! Attached to the clips are one set of contacts for the switch, and it was clear that both sides of both sets of contacts were burned. Than was where the high resistance was. Either the switch contacts can't take the multiple hours of 48A charging, or there is some type of chopping of the input current by the HPWC causing slight arcing which eventually burns the contact surfaces causing the high resistance. My electrician is coming tomorrow morning, and I'll see what she says. I'm a physics professor, and do a lot of my own electrical work, but a professional's opinion will be useful in this case.

 

[Bassdude2K]

You hired the wrong electrician. Was the electrician licensed? Master Electrician? Journeyman Electrician? Did he get a permit? Was it inspected?
Your panel is seriously damaged. You are lucky your house did not burn down. You must either replace the buss (if the damage isn't too expansive) or the entire panel.
STOP charging until the panel is replaced.
The guys over at Smart Charge America know this stuff inside and out and could potentially help you out.
I hope all goes well.

 

[ecospider5]

Wow, this is scary! I hired a Tesla recommended electrician to install mine back in 2019, not sure what Gen mine is, but I hope the electrician took care so that this type of thing doesn't happen. How do I ensure that mine has been installed correctly? Is an annual maintenance check is required? Really scares me as I have know a colleague whose parent died from a house fire.

Purchase a thermal camera or a temperature gun. $30-$300. Check the temperature of the breaker once or twice a year after a couple hours of charging. Get used to the Temperature. If you ever see a major jump of 20 degrees then something has changed and you should have it inspected.

In the data centers I have run we had thermal pictures taken of every panel regularly. We always had a circuit that was hotter than it should be. Re Torquing the screws and seating things almost always fixed it.