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

[btcrealm]

Agreed!
Very glad you guys are ok!
Hire another electrician, someone screwed that up!

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[btcrealm]

On the aluminum in home discussion.
I just had my power share installed yesterday. It is aluminum from the poll to the main breaker. Aluminum to the Tesla powershare unit. Aluminum from the powershare to the main house breaker panel.
Everything beyond that point is copper. To the charger from the Tesla powershare box as well.
Aluminum should only be on the service side. Not beyond that feeding anything to the house.

That looks like ground pairing with the aluminum and copper. I have never used aluminum for ground. I also use solid copper on ground (I've done up to 4AWG). This has all been network and telco related work and max 240V AC with conversion to 48V DC.

 

[Aces-Truck]

Here's my thoughts, as a homeowner who just did all electrical in my new Garage:
- In my state (WA), a homeowner is allowed to do the electrical work in their primary residence. Inspectors see this all the time. What they don't like is that many homeowners do their electrical without getting permits/inspections.
- IMHO, inspectors can miss things; especially when it comes to EV chargers. It's up to the person doing the electrical work to make sure it's right... then have the inspector be just a double check.
- I won't use AL wire anywhere inside my house. In fact I used CU to bring in 400A (320A continuous) down my mast. It's way more expensive than AL for large currents. But the benefit is that it doesn't tend to loosen due to heat related expansion/contraction over time. Day one, no difference. But after years of use, you REALLY need someone to re-torque your connections. That's true of CU as well. But not nearly as critical.
- As someone else pointed out in this thread, there is no requirement for a separate shutoff, except to protect an Eletrican working on the WC wiring in the future. My setup has the panel in sight of both WC's. I didn't have any issue with the inspector, nor in Tesla's instructions.
- If the wire was undersized, then there will be more heat due to losses. I can understand picking wire close to the limit, due to costs. Not necessarily a bad choice here. I just would rather pay more on wire for piece of mind. If any connections were not torqued enough, or loosened due to thermal cycling, those points will generate a lot of heat, which can add to the resistance, which creates even more heat. Based on the photos, the connections seem to be more of an issue than the wire sizing.
- We can all be armchair generals about second-guessing what was done, any why it failed. But in the end, what's important is that no one was hurt, and it will get fixed to prevent it from happening again.

 

[doggod]

I am not an electrician, but here are my best answers:

1) 6 gauge wire
2)
3) 60 amp breaker
4) 400 amp service (Two 200 amp panels)
5) Two 200 amp panels with 1 Tesla Wall Charger on each panel
6) Separate Panels
7) I estimate maybe 40 feet tops
8) 48 amps
9) 48 amps
10)
11)
12)
13)

I answered the ones I could.

Here are two more photos of the carnage. They believe the culprit was the piece that is in my Wife’s hand and it arched.

I was curious how they connected to wires. this appears to be the incorrect connector. on my solar setup the connecter has insulation around it, not bare metal.

 

[mongo]

I was curious how they connected to wires. this appears to be the incorrect connector. on my solar setup the connecter has insulation around it, not bare metal.

Split bolt connectors get wrapped in electrical tape, it burned off...
Still, that was the wrong split bolt for the application. Cu/Al versions aren't copper finished and have an additional piece that goes between the cables.

 

[doggod]

Split bolt connectors get wrapped in electrical tape, it burned off...
Still, that was the wrong split bolt for the application. Cu/Al versions aren't copper finished and have an additional piece that goes between the cables.

all solar in California uses the insulated connectors I show, maybe from different company. you cannot rely on tape to hold up in hot and cold situations. the glue always goes bad from temperature change. getting hot will just melt the glue.

 

[WoodChuckDad]

9 pages.....wow. Glad you came out ok. That splice bolt is the sort of thing that I use for electric fence. I wouldn't use it on house wire. For my charger I did a 60 amp breaker and 120 feet of 3AWG Aluminium from the main disconnect outside the house, to a 60 amp rated disconnect box, like you would have for an AC unit, then 25 feet of 6g thwn copper to the charger. both runs are in conduit. My charge is on a wooden post at the back corner of my house. I built the house and did most of the electric so I wasn't too intimidated by it, but I watched all the videos and read EVERYTHING I could find on the Tesla Website.

 

[cybercricket]

all solar in California uses the insulated connectors I show, maybe from different company. you cannot rely on tape to hold up in hot and cold situations. the glue always goes bad from temperature change. getting hot will just melt the glue.

It can't get hot though, that's the point. The only reason it got hot in this case is arcing. Here is what the AI calculated for a couple of examples :

4AWG copper @ 48A

Now 4AWG @ 48 Aluminum

I think the short copper run above was 6AWG, so just case another calculation

4AWG aluminum and 6AWG copper ended up giving the same result

 

[CyberGus]

 

[CyberGus]

I guess I'm not understanding what the split-bolts were for? My UWC was installed with unbroken, unspliced wire from terminals to breaker.

 

[cybercricket]

Right... I'd be not very inclined to lookup the formulas and do such math by hand, so AI is quite useful... assuming it's even remotely correct and doesn't BS us

 

[cybercricket]

I guess I'm not understanding what the split-bolts were for? My UWC was installed with unbroken, unspliced wire from terminals to breaker.

It looked like there may have been an existing drop for a 50A outlet or similar that they repurposed and needed to extend it a bit to wire into the Wall Connector.

 

[mongo]

Right... I'd be not very inclined to lookup the formulas and do such math by hand, so AI is quite useful... assuming it's even remotely correct and doesn't BS us

It's even simpler. The highest temp column is 90 C.
Electrical tape comes in 90, 105, 180, and even 260 C varieties so even the cheap tape shouldn't see it's limit. However, the 180 self fusing rubber type is often used followed by 105.

 

[mongo]

I guess I'm not understanding what the split-bolts were for? My UWC was installed with unbroken, unspliced wire from terminals to breaker.

To do most of the run in aluminum for cost savings, then switch to copper for the wall connector.

It looked like there may have been an existing drop for a 50A outlet or similar that they repurposed and needed to extend it a bit to wire into the Wall Connector.

It was new construction, I think the flex transition is due to needing to clear the garage door rails.

The summary version. This is a new home (new build) and the builder had two Tesla Wall Chargers installed as apart of their build out. So when we bought the home, it was already configured/live.

 

[CyberGus]

To do most of the run in aluminum for cost savings, then switch to copper for the wall connector.

100 feet of aluminum wire: fifty bucks
100 feet of copper wire: hundred and fifty bucks
Setting your house on fire: priceless

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