Gen 3 Wall Connector pulling 105 Amps?

[Bleedblue82]

Update for those interested... this morning's electrician came out, pulled the panel off, and immediately spotted that the inbound line (service --> board 1 --> this board, board 2) was not tightened and arcing under high load. Nothing to do with the HWPC at all beyond the fact that 40A load got the terminal hot enough to smoke. Unbelievable that the guy yesterday missed it.

Sure explains the smoke. Oh, and the service line to the HWPC was at a comfy 42A when the car was set to 40A. The dinosaur I got yesterday might be ready for retirement...

 

[brkaus]

Glad you got it sorted. And good that you are observant, noticed the smell, and took action.

 

[Droschke]

Electrician swapped the breaker for a brand new one; that one didn't trip either even when the car was set to 40A and amp meter showed 105A. I am more and more convinced electrician's amp meter was wrong.

So, all is good now or you are planning to install a new WC?

 

[Bleedblue82]

So, all is good now or you are planning to install a new WC?

all good. electrician doesn't see any issues with WC or the line. issue was all upstream - only reason I thought it was the WC is that the romex coming out of the board smelled like burning (because the terminal inside the board was burning)

 

[ninefiveone]

The munro video does a good job of highlighting the need to ensure everything in the charging pathway is rated for high duty cycle. Wiring, breakers, and junction connections need to be up to providing hours of the rated amperage and a lot of what's out there is meant for short-medium duty cycle like clothes dryers, etc.

 

[dannycamps]

my brand new install went through two breakers in two weeks. Got hot and tripped. 3rd was a charm and no issues since. The install was in 2017.

Electrician came by today to replace the breaker. Old breaker was literally burnt/melted on the back of it on one of the poles (yikes). Electrician said he had never seen anything like that before.

After install of new breaker, things look okay and was able to charge the car for an hour with no issue so cautiously optimistic. Will keep an eye on it for a while.

 

[mswlogo]

if it was arcing upstream it can cause trouble all over. It might have even caused his meter to measure wrong.

 

[brkaus]

Electrician came by today to replace the breaker. Old breaker was literally burnt/melted on the back of it on one of the poles (yikes). Electrician said he had never seen anything like that before.

After install of new breaker, things look okay and was able to charge the car for an hour with no issue so cautiously optimistic. Will keep an eye on it for a while.

We had a panel that had a stab (or whatever you call it) melt because of arching to the breaker. The melted metal dropped down to the next stab on the other phase, shorted, and exploded. Melted most of the bus bar and sent molten metal blobs into the garage. Melted spots into the windows of a car parked close.

 

[Dave EV]

Update for those interested... this morning's electrician came out, pulled the panel off, and immediately spotted that the inbound line (service --> board 1 --> this board, board 2) was not tightened and arcing under high load. Nothing to do with the HWPC at all beyond the fact that 40A load got the terminal hot enough to smoke. Unbelievable that the guy yesterday missed it.

Sure explains the smoke. Oh, and the service line to the HWPC was at a comfy 42A when the car was set to 40A. The dinosaur I got yesterday might be ready for retirement...

#1 cause of overheating in charging circuits - loose lugs / connections. People either fail to torque the lugs to the equipment properly and they loosen up after a few heat cycles, or they fail to properly insert the wire into the lug and it still loosens up.
#2 cause of overheating - equipment that isn't designed to handle 80% of their rated value for hours.

Electrician came by today to replace the breaker. Old breaker was literally burnt/melted on the back of it on one of the poles (yikes). Electrician said he had never seen anything like that before.

After install of new breaker, things look okay and was able to charge the car for an hour with no issue so cautiously optimistic. Will keep an eye on it for a while.

This is not an uncommon failure as well - I'm surprised the electrician hadn't seen it before. All it takes is an older breaker and/or breaker box with a bit of corrosion on the busbar and some higher currents. For this reason, a bit of dielectric grease on the breaker contacts and lugs is not a bad idea.

Most electrical equipment in your typical house doesn't see the loads that a EV generates - air conditions or heat pumps are probably closest. Everything else generally cycles on/off pretty frequently that the average duty cycle isn't that high.

 

[Droschke]

Electrician came by today to replace the breaker. Old breaker was literally burnt/melted on the back of it on one of the poles (yikes). Electrician said he had never seen anything like that before.

After install of new breaker, things look okay and was able to charge the car for an hour with no issue so cautiously optimistic. Will keep an eye on it for a while.

What amp setting were charging at on the old breaker?

 

[dannycamps]

This is not an uncommon failure as well - I'm surprised the electrician hadn't seen it before. All it takes is an older breaker and/or breaker box with a bit of corrosion on the busbar and some higher currents. For this reason, a bit of dielectric grease on the breaker contacts and lugs is not a bad idea.

Breaker was new when installed last year (2021) when wall connector was installed. Breaker box is only 10 years old (house built in 2011). It appears to have just been a defective breaker that wasn't able to properly handle the load.

What amp setting were charging at on the old breaker?

50A circuit w/wall charger set to 40A. All wiring, etc... rated to code to handle EV charging (read: constant) loads.

 

[Droschke]

50A circuit w/wall charger set to 40A.

I meant the amp setting on the car (sorry for not being clear). Was your car set to charge at full 40 amp or less?

 

[sorka]

Could his amp meter be wrong, sure. But the burning smell lends credence to something going awry.

His meter is wrong and you can still have overheating from improperly tightened lugs at the normal current.

 

[sorka]

I talked to Tesla as @DerbyDave kindly suggested - they think it's a ground fault (high temp at terminals). I coincidentally had a mobile tech out today and he thinks the unit's probably faulty given sudden failure, but I'm getting (another) electrician to come check the boxes for tesla so I can get it warrantied out. Talk about a PITA... my last wall charger went for three years without one single tiny modicum of issues...

The charger would not charge if there was a ground fault. It's pretty smart about that.

 

[sorka]

Update for those interested... this morning's electrician came out, pulled the panel off, and immediately spotted that the inbound line (service --> board 1 --> this board, board 2) was not tightened and arcing under high load. Nothing to do with the HWPC at all beyond the fact that 40A load got the terminal hot enough to smoke. Unbelievable that the guy yesterday missed it.

Especially since that's the FIRST thing you check.

 

[dannycamps]

I meant the amp setting on the car (sorry for not being clear). Was your car set to charge at full 40 amp or less?

Yes - car set to 40A.

 

[whitex]

The munro video does a good job of highlighting the need to ensure everything in the charging pathway is rated for high duty cycle. Wiring, breakers, and junction connections need to be up to providing hours of the rated amperage and a lot of what's out there is meant for short-medium duty cycle like clothes dryers, etc.

The specs of the breakers and junctions boxes actually requires them to sustain 80% load indefinitely. Perhaps some manufacturers produce crap and have been getting away with it at low duty cycles, and that's being exposed by EV charging. That said, I come from long line of electrical engineers and electricians (both my parents, one grandparent. aunts and uncles) and I've seen and heard of my share of meltdown failures (including some which would never happen at home, having to do with very high voltage lines), Yes, equipment does fail from time to time - no equipment is perfect, More often than not however, it's an installation issue such as not torqueing the connections as they should be, or doing stupid things like using aluminum wires connected directly to a breaker without an adapter for example, or even a damaged cable (perhaps damages before the installation, someone drove over it with a forklift at the warehouse).

 

[ninefiveone]

The specs of the breakers and junctions boxes actually requires them to sustain 80% load indefinitely. Perhaps some manufacturers produce crap and have been getting away with it at low duty cycles, and that's being exposed by EV charging. That said, I come from long line of electrical engineers and electricians (both my parents, one grandparent. aunts and uncles) and I've seen and heard of my share of meltdown failures (including some which would never happen at home, having to do with very high voltage lines), Yes, equipment does fail from time to time - no equipment is perfect, More often than not however, it's an installation issue such as not torqueing the connections as they should be, or doing stupid things like using aluminum wires connected directly to a breaker without an adapter for example, or even a damaged cable (perhaps damages before the installation, someone drove over it with a forklift at the warehouse).

I won't guess at ratio of sub-par equipment vs sub-par installation. I do think we'll see a correlation of sub-par installations also using sub-par equipment.

 

[EVer Hopeful]

I'm not sure 105A going through a 50A breaker would actually trip it


I think it might be something more like this:

...and no, this has nothing to do with my or anyone else's EV

 

[VT_EE]

His meter is wrong and you can still have overheating from improperly tightened lugs at the normal current.

I wonder if he had the meter set to hold the max value. If it got a reading during an arch event, it's possible he did get an instantaneous reading of 100amps.