Buzzing sound coming from my breaker on the panel.

My Ioniq 6 is capable of using a higher amp L2 charge. So I bought a 40A Grizzle EVSE. The breaker is 50A. When I charge the I6 there is a buzzing sound (not really loud) coming from the breaker. It is warm to the touch, but not hot. The car dash shows 9.3 kW charge rate.

What is causing this, or what does this mean? Do the connectors at the breaker need to be tightened? I did try shutting the breaker on and off, but doesn't make any difference. Is the breaker faulty?

 

It is #6 AWG. I should mention that when I charge the Solterra there is no buzzing. That's likely because it only draws 6.6 kW unlike the I6 which draws the full 9.3 kW that the Grizzle allows. I may take off the panel and torque up the connectors. Hate doing that though, as shutting off the main panel means resetting a lot of stuff in the house. And maybe while the panel is off look at putting in a 60 or 70A breaker.

I have often checked the charge port on the I6 and it is never hot, barely even warm. I am well aware of the ICCU issues with the I5/I6, so right after I bought it, had the dealer do a check and software update for it. That was the first TSB, and maybe that prevented further charging problems at the car end. I understand there is another TSB or recall coming with another software update so will do that as well, just to be safe. The rest of the car has been rock solid with everything, and very happy with it. Over 10K kms on it already. The Solterra has over 20K kms now, and also has been rock solid.

 

I can reduce it in either. I am sure if I did, the buzzing would stop. Like I said, the Solterra charges at 6.6 kW and no buzzing. So it seems only the higher amp load does it.

Do you think it is the breaker? IE, can't handle the higher load? Having said that, the car charges fine, but I don't like that buzzing sound.

 

Thanks, EE, all great advice. Not sure when I will shut off the panel and take off the lid. Like you said, need to pick the right time, incl when I have time. Meanwhile, I am going to throttle down the charging rate at the car, and I expect the buzzing to stop then. As I mentioned earlier, no buzzing with the Solterra which does draw a lower charge. So that points to something changing, either some connections need to be tightened, or the breaker becoming faulty.

One other thing I should mention. This buzzing just started a couple weeks ago. Previously, for last 8 months or so since I got the I6, there was no buzzing, and the car charged at 40A no problem.

Also, this buzzing sound reminds me of our hangar electrical room down at the airport. Lots of buzzing going on in there with all the high powered electrical equipment. And quite a bit of heat, too, so ventilators come on as required, esp in the summer.

 

Problem is fixed, replaced breaker, and no more buzzing. But let me tell you what I did. I wanted to try a few steps before finally installing the new breaker.

I first checked all the wire terminal ends and tightened them, incl on the breaker. But buzzing continued. I then removed the old 50A breaker, checked it over, but could not see anything wrong. I reinstalled it, thinking maybe reseating it might help. But no, the buzzing returned. So last step, I replaced the breaker with a 60A one, and no more buzzing now.

So I assume there must be something wrong with the old breaker. Or the extra capacity 60A one just does a better job of handling the 40A load. The 50A breaker has been in the panel for 20 years or more, for a welder (6-50 receptacle). I only started using it again when I got the I6 last July and a 40A Grizzle EVSE with a 3 prong 6-50 plug. Worked fine until a couple weeks ago, when the buzzing started.

 

While I may be curious as to why the breaker failed, I don't have the tools or will to take it apart. I am sure that this is not the first failure of this type, so there must be info on the internet about what causes the buzzing. I am just glad with the help and advice from you guys, that I got it fixed. Thank you.

 

When I searched for why circuit breakers buzz, I found this answer. Interesting, but I never tried the remedy.

I did use to turn the breaker on an off, like a switch, when I wasn't charging, because I didn't want to waste electricity with the EVSE always on. And I knew plugging and unplugging wasn't good for the receptacle. Maybe that wore something out on it. Now I am just leaving it on.

I put the old breaker into my electrical stuff bin, but labelled it as BAD. So I could always do some more experimenting with it. Trouble is that it works fine with a 32A load. It just buzzes at 40A load.

Buzzing breakers are not normal, but a common problem. The usual cause is an unseated magnet vibrating in the breaker. These magnets sometimes do not reseat into the correct position after tripping and resetting. This can cause the breaker to not lock into "on" position or hum under load. I am not sure if this trick will work on a AFCI breaker, but on regular breakers, we remove them and give them a firm slam on it's side. This sometimes jolts the magnet back into the correct position. You can then operate the breaker on and off a few times to confirm it is seated and operates freely. I have not experienced this sound with a AFCI yet. So the sound could be the magnet vibrating or a defective coil. When I attempted to reseat a magnet and it didn't correct after a couple of "slams", or the condition returned after a trip again, I replaced the breaker. Obviously there could be another problem and the breaker should be replaced, but the slam trick can be very effective.

 

No, I certainly didn't switch it on or off under load. Only when the plug is out of the car.

But this brings up another question. I can do scheduling at the car, or at the Grizzle (has wifi). If I use the Grizzle does it just turn on, and how does the initial car handshaking work then?

Which way is better? As you know we have time of day rates coming, and I might want to take advantage of that.