Buzzing sound coming from my breaker on the panel.

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R P

R P

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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?
 
My guess is the breaker is at fault. There may be more expensive, solid state ones that don't operate on temperature yet provide safety. Perhaps good friend @hobbit might have some thoughts.

Bob Wilson
 
Should the breaker size be smaller for this application anyways? like a 45amp breaker instead or something? Is it a cheap breaker thats installed? If its a really cheap brand then maybe that could be the problem. I don't think many of these larger breakers were made with the assumption that the load would run sustained for as long as a car would charge. A similar thing is true with a lot of the more 'normal' residential 14-50 plugs too. Maybe some connections are loose or something.
 
R P said:
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?
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Need to know the AWG size of the wires and make of panel (send picture -panel open). It is possible the breaker is defective.
If #6 AWG, than a 2 pole 70A is permitted by code (Table-13) 61-70A - ampacity of conductor (Table 2) @ 75 degree column - the ampacity of 90 degree #6 conductors is actually 65A.
I would start there, and of course check torque on the conductors are tight and the breaker as well (if it is a bolt on), also bus bar where the breaker mounts is not discolored(blue).
The other thing that may be opening a can of worms, is the ongoing overheating @ the charge port (I6 owner) of E-GMP CCS equipped EVs when AC charging at maximum level of 48A, in conjunction with the throttling Hyundai has applied as a fix.
Video showing I5:

Just keep an eye on the charge port inlet temp, either by software or heat detection unit, and keep below maximum setpoint ~ 223 degrees C.
BTW - a 60A breaker should hold it's load -continuous or not - @ 80% (48A) all day long, however by changing it to a 2P 70, you are well clear of that (70 *.8=56A), wiring permitted of course.
 
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electriceddy said:
Need to know the AWG size of the wires and make of panel (send picture -panel open). It is possible the breaker is defective.
If #6 AWG, than a 2 pole 70A is permitted by code (Table-13) 61-70A - ampacity of conductor (Table 2) @ 75 degree column - the ampacity of 90 degree #6 conductors is actually 65A.
I would start there, and of course check torque on the conductors are tight and the breaker as well (if it is a bolt on), also bus bar where the breaker mounts is not discolored(blue).
The other thing that may be opening a can of worms, is the ongoing overheating @ the charge port (I6 owner) of E-GMP CCS equipped EVs when AC charging at maximum level of 48A, in conjunction with the throttling Hyundai has applied as a fix.
Video showing I5:

Just keep an eye on the charge port inlet temp, either by software or heat detection unit, and keep below maximum setpoint ~ 223 degrees C.
BTW - a 60A breaker should hold it's load -continuous or not - @ 80% (48A) all day long, however by changing it to a 2P 70, you are well clear of that (70 *.8=56A), wiring permitted of course.
Click to expand...

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.
 
Do you have an option to reduce the charge current in either the vehicle or charging station?

For example, both my JuiceBox 40 and Tesla Model 3 have the ability to limit the charging current.

Bob Wilson
 
bwilson4web said:
Do you have an option to reduce the charge current in either the vehicle or charging station?

For example, both my JuiceBox 40 and Tesla Model 3 have the ability to limit the charging current.

Bob Wilson
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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.
 
I have the same car and evse. Mine is set to 40 amp on a 50 amp breaker.
I get 9.5 kW.
Going to 60 or bigger amp breaker may cause issues for a 40 amp evse…..or so I’ve read and been told.
 
R P said:
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.
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There will always be a certain amount of variability in any manufacturing. Your symptoms are consistent with a contact chatter and the heat. Reducing the maximum charging is just a workaround until that breaker is replaced.

I'm not having a lot of luck Googling applicable, solid-state, circuit breakers. But the advantages are:
  • no resistance heat losses - a warm breaker is converting some current($) to waste heat
  • arc less - tripping does not pit and age the contacts
  • easier reset - you're not fighting the spring
  • ground fault detection - safer
  • enhancements - monitoring capabilities and self reset
They will be more expensive than the typical $15-25 ones. But over time the lower heat loss will offset the price. Remember a hot circuit breaker is warming the others which derates their current limit (i.e., makes it easier for them to trip.)

Apparently there are thermal magnetic circuit breakers that are less sophisticated but provide better protection than a standard thermal breaker:
Bob Wilson
 
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R P said:
Do you think it is the breaker?
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After checking for connection issues, perform a current draw with a clamp on meter. Also check voltage under load. If within specs and the breaker is still exhibiting a low buzz or hum sound when standing next to panel...replace it as above indicated.
You may already have another breaker in the panel you could substitute it to check if noise stops (temporary).
rcarter3636 said:
ine is set to 40 amp on a 50 amp breaker.
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That is the maximum size load the breaker will handle on a continuous basis. When it comes to EVSE installation, I tend to use #6 with 90-degree insulation. Because the equipment, (panel) is only rated 75 degrees TTR (termination temperature rating), the ampacity must be based on this column. In Canada... that is 65A, which is permitted to install a 70A breaker (see table 13).
rcarter3636 said:
Going to 60 or bigger amp breaker may cause issues for a 40 amp evse…..or so I’ve read and been told.
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It depends on which value of overcurrent is derived.
Speaking as a current master electrician in 2 provinces (35 years in the trade), I can tell you the first use the equipment specifications - if the equipment manufacture specifies a minimum circuit ampacity and a maximum overcurrent value, then follow it (providing it does not impede the local electrical code). If the manufacture specifies -"wire according to local code", then that will apply.
We have always tended to use minimum circuit ampacity with maximum overcurrent protection- to keep costs down (competitive). But with EVSE equipment and the EVs on board chargers getting larger with time, it is best practice to use a larger circuit ampacity than required for futureproofing...also to avoid the issue being discussed above by putting the overcurrent device at its maximum limits.
bwilson4web said:
Apparently there are thermal magnetic circuit breakers that are less sophisticated but provide better protection than a standard thermal breaker
Click to expand...
Agreed, but try to find an approved one that fits into your existing panel.
bwilson4web said:
They will be more expensive than the typical $15-25 ones. But over time the lower heat loss will offset the price. Remember a hot circuit breaker is warming the others which derates their current limit (i.e., makes it easier for them to trip.)
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I don't think I have seen a breaker recently that even comes close to those prices. But maybe in the States it is different.
The nature of thermal breakers tend to indeed run warm at or near maximum capacity (this is normal and is how the overload mechanism works to lead to a trip event). This is the reason to wire a circuit with ampacity better than the minimum requirements.
electriceddy said:
make of panel (send picture -panel open)
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Send a picture, PM if you want- and I will advise of type, price and local location to find a replacement - after you have checked for connection issues as advised. If you have to shut off the main to do it, don't do it on a Sunday as BC Hydro charges double for meter removal to allow for main breaker replacement if it doesn't reset... a condition I have experienced before when the breaker has not been properly exercised - generally once every 3-5 years (no-load condition).
 
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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.
 
bwilson4web said:
Take a Dremel to it and inspect the contacts. I’d like to see their state.

If you have a VOM, check resistance?

Bob Wilson
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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.
 
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R P said:
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.
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You could always ship it to Bob for some detailed forensic investigation, it might be interesting to view the final analysis:D
 
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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.
 
R P said:
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.
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This method is not recommended as a routine procedure unless the breaker has a "SWD" rating.
Because the EVSE has to "handshake" before energizing the load (EV), the initial turning on of the rated breaker only energizes the EVSE electronics, so not an issue of turning on full load conditions. Turning off I would not do under full load, wait until the charge cycle is done.
Used mostly in commercial lighting systems, also "HID" breaker ratings as well.
The mechanics of a non-switch rated breaker used for this type of energizing/de-energizing full load on a continuous basis will lead to premature failure.
 
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electriceddy said:
This method is not recommended as a routine procedure unless the breaker has a "SWD" rating.
Because the EVSE has to "handshake" before energizing the load (EV), the initial turning on of the rated breaker only energizes the EVSE electronics, so not an issue of turning on full load conditions. Turning off I would not do under full load, wait until the charge cycle is done.
Used mostly in commercial lighting systems, also "HID" breaker ratings as well.
The mechanics of a non-switch rated breaker used for this type of energizing/de-energizing full load on a continuous basis will lead to premature failure.
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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.
 
R P said:
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.
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Now we are getting into equipment specifications.
It really won't matter which calls for charging initialization, either the car will request the control circuit to engage the charging relay(s) in the EVSE, or the WIFI command. The power will have to left on the EVSE for the WIFI circuitry to operate, same if the car is programmed to initiate the charging sequence. So there will always be a slight drain to operate the electronics in the WIFI (or not) EVSE. Additionally, the car will have to be tethered in order to communicate (plugged in).
Some power companies poll the equipment thus gaining their required information that way, so WIFI may have an advantage there. BC Hydro (TOU plan) will not work that way, they have separate communication with their meters.
I rarely use my EVSE at home, the breaker is almost always off, so no phantom drain.
 
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