Almost Burned my House Down... Thoughts / Theories?

[ModelXer]

stranded wire in higher gauges because solid would be unusable at that size.

But as noted elsewhere, aluminum connections have to be torqued down, not twisted, and copper in those gauges should be as well. Also, there are torque specs for the connections in the wall charger... which I followed when I installed my wall charger.

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[PungoteagueDave]

Aluminum clearly does meet code in some states. We built a new home in MD last year. The builder included an EV charger outlet (1450) as an option, which we selected. Upon adding a second WC, solar panels, and Powerwall, we discovered that the electrician had used #6 aluminum romex wire for the first wall charger. We left it in place and added another breaker, conduit and #4 copper to a new box for the first WC to mount next to the existing 1450 outlet that retains the aluminum wiring. Expensive to do, but provides the benefit of full 48 amp support at both of the Tesla WCs and allows the 1450 outlet to provide easy charging of non-Tesla EVs or to run 240v tools.

 

[REM]

Still, isn't it bad practice to rely on a downstream connection for grounding though? Sort of like not using a duplex outlet as neutral continuance for a split neutral branch circuit .
I thought BX isn't allowed as ground in new installs anyway?

oh, for sure. definitely not the textbook correct way to do it, and I wouldn't try to pass it in a professional installation... however, I have done it a couple of times on my own side projects.

one of those "meh .001% chance it could come back to bite me" type of scenarios.

 

[syburtruck]

Guarantee you need a master electrician to look at it and document it. I have two of the same connectors in my garage and if you saw the conductors used I think you might see a difference. I won't say anything beyond that what's already been said here. And I am glad you had cameras.

 

[Mr Sir]

Also very glad it wasn't worse. That said, this one appears easy.
First, an "Oxide inhibitor" doesn't appear to be present. Nothing at all wrong with aluminum wire but this product must be used to prevent arcing and loose connections. The Conductors must be correctly tightened/torked.
Next, it also appears that both units/Chargers were under one (1) circuit breaker. If this is true, you would need #2 Copper wires, not #6 aluminum (which is okay for one btw). You can confirm this if both were controlled by only one 60 amp (2 pole) breaker. I am curious though

 

[mongo]

Also very glad it wasn't worse. That said, this one appears easy.
First, an "Oxide inhibitor" doesn't appear to be present. Nothing at all wrong with aluminum wire but this product must be used to prevent arcing and loose connections. The Conductors must be correctly tightened/torked.
Next, it also appears that both units/Chargers were under one (1) circuit breaker. If this is true, you would need #2 Copper wires, not #6 aluminum (which is okay for one btw). You can confirm this if both were controlled by only one 60 amp (2 pole) breaker. I am curious though

Along with missing the anti-oxide, it wasn't an aluminum to copper split bolt .
The Polaris IT Black is prefilled, so wore just needs a brushing if there is oxidation.

Wall Connectors were on individual breakers from separate panels:

5) Two 200 amp panels with 1 Tesla Wall Charger on each panel

 

[Trekboy]

Still, isn't it bad practice to rely on a downstream connection for grounding though? Sort of like not using a duplex outlet as neutral continuance for a split neutral branch circuit .
I thought BX isn't allowed as ground in new installs anyway?

edit: Ok, I see now you were not talking about multiple ground points, but on relying on the metal conduit to ground that box. Ya, I agree that it would be best practice to have a grounding lug in that box. That's what I would do if it were my house.

 

[Bridgeboy69]

 

[Jimo]

Last night at 9:12 pm, I got a “communication error” while charging my CyberTruck. It stopped charging at 41%. I went out to the garage to check and the entire garage was filled with smoke. The breaker tripped and the Cybertruck appears to be okay. The home was built in November 2024. Moved in April 2025. We have two Tesla Wall Chargers.

The builder sent our the company who did the electrical work and they are here now.

Thoughts?

Looks like a loose connection. I have seen that even with Dryers and ranges. BTW that's what breakers are for!

 

[TARS69]

What gauge wires are they and what size breakers? How many amps are you drawing when you're charging? Glad it didn't cause a fire!

 

[donnymcdoodles]

A manual shutoff within direct sight of every WC or other EV charger is both code and a specific requirement in the Tesla installation instructions.

The installation manual for the Tesla Gen 3 charger specifically states that

A manual shutoff within direct sight of every WC or other EV charger is both code and a specific requirement in the Tesla installation instructions.

FYI, the installation manual for the Tesla Gen 3 charger specifically states that “External disconnect switches are neither required nor recommended.”

Page 9: https://digitalassets.tesla.com/tes.../gen-3-wall-connector-installation-manual.pdf

 

[donnymcdoodles]

It is also my understanding that installing a disconnect “for code” is not really so you can quickly turn it off when things go wrong… it is so that someone working on it has line-of-sight assurance that the line is not energized.

That is also why some jurisdictions are apparently fine with you just putting a lock on your breaker box on the other side of the house.

 

[Vagis9780]

1) don't allow that installer to return and inspect for any reason.

2) find out who your installer is insured/bonded under, and file a claim with them. insist that they send out a qualified investigator to document what happened.

3) follow through with a claim with the insurer to replace ALL damages.

I have seen shoddy electricians come back to "see what happened" only for them to try and erase evidence of wrongdoing or laziness. everyone makes mistakes, but this is probably a case of extreme negligence.

note: that looks like aluminum wire to me. Not sure why tf anyone in their right mind would would be using that for an EV charger. Prone to disasters just like this.

Looks to be 4 awg aluminum wire from breaker box to junction box (used aluminum to save cost), with 6 awg copper from junction box to charger?? Why not skip junc box connection by going straight into back of Tesla charger with 4 awg wire. I agree, this poor workmanship.

 

[mongo]

Looks to be 4 awg aluminum wire from breaker box to junction box (used aluminum to save cost), with 6 awg copper from junction box to charger?? Why not skip junc box connection by going straight into back of Tesla charger with 4 awg wire. I agree, this poor workmanship.

Wall Connector doesn't allow aluminum conductors .

 

[mongo]

Looks like a loose connection. I have seen that even with Dryers and ranges. BTW that's what breakers are for!

What are breakers for?
Only AFCI breakers trip on loose connections/arcing, GFCI and standard do not.
AFCI only come in 15 and 20 amp versions, not 60.
Ideally, Wall Connector is fed by a standard breaker as GFCIs can nuisance trip due to capacitive leakage current.

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