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HPWC Burned Up (Yikes!)

My charge cycle was interrupted 2 days in a row. I unplugged it and replugged it in the AM and everything seemed fine. ( but called Tesla to have them check the car out ) Just came back from work and figured I'd crack open the HPWC (Yes I flipped the breaker off first) because I thought I smelled that ozone smell... and here is what I found :

burnedup.jpg


The heck would cause the wiring on the TESLA cable side to burn up like this? Kind of looks like something arked across the bridge there.

Should note that the car seems fine, and I charge at 40A even though the HWPC is on 100A breaker. I did charge once at 60A a few weeks back.
 
The last time I had something like this happen (on other electronics, not on an HPWC) was when there was a lightning strike close to my house (to lamp post in front of house) - it caused an EMP enough to burn up some electronics in a similar way. Have you had some monster thunderstorms in your area right before this?
 

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
6,162
14,860
Hickory, NC, USA
Looks like high resistance/bad connection on the crimped connector on the black wire causing excess heat, possibly even the screw holding it being loose. I strongly urge you not to use it anymore. From the looks of it the wire has heated enough to burn the insulation, which means it got really really hot and is no longer safe even if the crimp or connection is fixed. It's a fire hazard and should be locked and tagged out until a replacement is installed.
 
What was your amperage setting? Others have reported high temperatures for their units, but they were able to mitigate the problem by reducing the amperage (e.g. to 70 A, instead of 79 A).

The charger is set to 80A, but I charge the car on 30-40A. (Usually 30A) Bought the HPWC so I could get a quick charge if I needed too. I've only once ran it anywhere close to 80A and that was the first week I got the car just to see how quick that charge goes. Tesla support called back, they are going to send someone out from the local service center to look at it. I'm not going to mess with it untill they come by and look/replace it.

Visibly nothing looks like its loose in there or anything, (like i said not touching anything in there until the service rep pokes at it ) . It was installed by the electrician Tesla told me to use. The unit looked like it still had power when I came home as the green light on it was still on. Good thing my paranoia made me pop it open before plugging the car into it this evening.
 
Yes it is a good thing that you inspected it, close call and good catch.

i wonder what sort of current sensor that is--i've never seen one used like that with both wires thru the toroid as it would seem that the ac currents would cancel each other.

Maybe the toroid only sees a difference if one wire is carrying less current than the other like when there is a leak?
 

Rocky_H

Well-Known Member
Feb 19, 2015
8,597
11,159
Boise, ID
I can't help getting a bit of a chuckle when I see these threads about HPWCs overheating, burning, melting because so often I see all these people telling everyone to get the HPWC, even if it's still on a 50A breaker because it's so much better/safer than the UMC because it's hard-wired and so much more heavy duty, etc. etc. Eh, maybe not so much.
 
My suggestion: As long as your getting your HPWC replaced, you may as well wire in a nema 14-30 or 14-50 outlet off of the same circuit/breaker box. I did this arrangement (about $50 in extra parts) so I could use either the HPWC or my UMC, (since 30A is fine in most cases for overnight charging), and you get a back-up if either HPWC or UMC fail.
 

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
6,162
14,860
Hickory, NC, USA
Yes it is a good thing that you inspected it, close call and good catch.

i wonder what sort of current sensor that is--i've never seen one used like that with both wires thru the toroid as it would seem that the ac currents would cancel each other.

Maybe the toroid only sees a difference if one wire is carrying less current than the other like when there is a leak?

It is for the ground fault protection circuit so it only really matters if there is an imbalance since either line to ground would imbalance one and set off the protection.

If you ever look closely there is even a small lead wrapped around the coil that is used to test this circuit automatically.
 
I can't help getting a bit of a chuckle when I see these threads about HPWCs overheating, burning, melting because so often I see all these people telling everyone to get the HPWC, even if it's still on a 50A breaker because it's so much better/safer than the UMC because it's hard-wired and so much more heavy duty, etc. etc. Eh, maybe not so much.

So you anticipate there will be no electrical component failures? That is a dream!!
This failure is of no consequence and occurred as anticipated with minimal risk to property and people.

Now for the reality!!

The greater safety of the HPWC comes from the fact that the failures (heat & sparks) are contained within the HPWC's UL rated electrical enclosure, designed to safely contain the electrical failure event.

However, the UMC (a non-NRTL listed device) and the typical failure (heat & sparks) occurs at the adapter plug/wall receptacle which is outside a rated electrical enclosure and as with any typical cord connected equipment is more likely to cause a structure fire by igniting flammable materials cluttered near by.

This is no joke and nothing to chuckle about as if it happens it will not be funny since a fire caused by unattended electrical equipment is often life threating.
So I will use the HPWC with the confidence that it is a NRTL listed device which is designed to fail with minimal risk to the structure and people sleeping inside.
 
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My suggestion: As long as your getting your HPWC replaced, you may as well wire in a nema 14-30 or 14-50 outlet off of the same circuit/breaker box. I did this arrangement (about $50 in extra parts) so I could use either the HPWC or my UMC, (since 30A is fine in most cases for overnight charging), and you get a back-up if either HPWC or UMC fail.

Cephellow, could you post a picture of your setup. I just installed a HWPC on an 100amp and it tripped my house power twice at 80amps. With a meter in place and everything on I didn't not pass 85amps at any given time. Replaced a few breakers showing wear and tear and blue indications on the bolt heads. Shut off the breaker to the HWPC while at work tonight and will revisit in the morning.

~MJ
 

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
6,162
14,860
Hickory, NC, USA
Cephellow, could you post a picture of your setup. I just installed a HWPC on an 100amp and it tripped my house power twice at 80amps. With a meter in place and everything on I didn't not pass 85amps at any given time. Replaced a few breakers showing wear and tear and blue indications on the bolt heads. Shut off the breaker to the HWPC while at work tonight and will revisit in the morning.

~MJ

Sounds like you don't have sufficient capacity in your panel for charging at 80A.
 

AmpedRealtor

Well-Known Member
Jun 30, 2013
6,433
4,166
Phoenix, AZ
I can't help getting a bit of a chuckle when I see these threads about HPWCs overheating, burning, melting because so often I see all these people telling everyone to get the HPWC, even if it's still on a 50A breaker because it's so much better/safer than the UMC because it's hard-wired and so much more heavy duty, etc. etc. Eh, maybe not so much.

This is the first report that I've seen of any such HPWC issue, whereas I've read many more reports of UMC failures. In fact, didn't Tesla recall one of the UMC connectors a couple of years ago? The vast majority of HPWC installs are rock solid.
 

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,030
1,030
My suggestion: As long as your getting your HPWC replaced, you may as well wire in a nema 14-30 or 14-50 outlet off of the same circuit/breaker box. I did this arrangement (about $50 in extra parts) so I could use either the HPWC or my UMC, (since 30A is fine in most cases for overnight charging), and you get a back-up if either HPWC or UMC fail.

Just as a quick note - you may not install a receptacle off the same circuit if the HPWC is configured at greater than 50A. But having a backup 14-50 receptacle for your UMC is a good idea as a back-up.

- - - Updated - - -

Cephellow, could you post a picture of your setup. I just installed a HWPC on an 100amp and it tripped my house power twice at 80amps. With a meter in place and everything on I didn't not pass 85amps at any given time. Replaced a few breakers showing wear and tear and blue indications on the bolt heads. Shut off the breaker to the HWPC while at work tonight and will revisit in the morning.

~MJ

If your main breaker is tripping, it means either you're considerably exceeding the rating for your main breaker, or you have a defective main breaker. What is the breaker rated at?
 

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