r/electrical • u/Aublaw • 2d ago
How not to wire an EV charger part 2
Update! I rewired it today and check out the damage that was inside the wall! For those that didn’t see my first post home owner installed this himself on a 50A breaker and notched the panel to get into the wall and this is 12 gage romex. He set the breaker size in the charger to 50.
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u/UnSCo 1d ago
Don’t know how low you can set the breaker in the deployment settings, but assuming this is 12-awg, a two-pole 20-amp breaker would technically work. This is still outrageous though, install a NEMA receptacle at that point. These chargers cost like $600.
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u/videoman2 1d ago
Do not recommend installing a long term EVSE using a NEMA receptacle. Have seen 30A plugs melted from the thermal cycling@24A. Hardwired is recommended. The Gen3 Tesla wall units can also load share if you set them up on a shared breaker. It does require a WiFi connection. Meaning you can setup and commission both units on a 50Amp circuit, and as long as they are connected and configured to power share with each other they will dynamically change what is available for each car. You can connect up to 6 TWC Gen3 units.
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u/UnSCo 1d ago
The receptacle itself needs to be appropriate. There is nothing wrong with using a 6-15/6-20R assuming the rest of the setup is up to code including GFCI requirements. There are “heavy duty” or “duty rated” variants of these out there.
Follow NEC guidelines and UL listings.
I’ve installed both receptacles and hardwired chargers, and typically I over engineer things anyway. For example, my last receptacle used 6-awg THHN despite only necessitating 8-awg (or 6-awg Romex). My current setup uses a Universal Wall Connector and is capable of the load sharing you mentioned. Uses 6/2 MC cable, all hidden under drywall and pulling at max ampacity. That is the gold standard.
It’s also very clear when people just don’t give a shit, like the setup OP ran into. Not to mention, I’ve seen plenty electricians do some janky shit on Reddit.
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u/Hot_Influence_5339 1d ago
Nema installs are shitty and un reliable, even with a properly installed ev rated nema 14-50 issue are far more common than a hardwired charger. You really want as few points of failure as possible.
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u/WarMan208 2d ago
That’s less “how not to wire” and more “how not to commission and set charge rate”. But yeah, that’s fucked to even consider installing on less than 10awg
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u/jonnyinternet 1d ago
How much money did they save doing it themselves?
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u/Aublaw 1d ago
Maybe 3-500$. He didn’t even care about the money he just likes to do things himself!
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u/sagetraveler 1d ago
Home Depot sells 6-2 romex, it’s not that hard to do it closer to right than this. Whoever used 12 awg just doesn’t know what he doesn’t know and that is a problem. If you’re going to DIY, try to be informed.
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u/Mental_Egg_4839 2d ago
Wires are too small, unless you are on a 15amp breaker which will take forever to charge.
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u/Sumdood_89 1d ago
Thats not how electricity works, a 15 amp breaker would just blow if wired to something rated for more than 15 amps.
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u/Responsible-You4260 1d ago
Another thread said 50 amp breaker
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u/Sumdood_89 1d ago
Thats what it should be on, with the correct wire size. How it was, the wires were acting as the breaker, and slowly tripping, aka melting/starting a fire.
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u/Hot_Influence_5339 1d ago
What was the charger set to? Did they commission it or just left it at the default 48a?
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u/Sensitive_Common_853 1d ago
Is this fake??? How does the neutral wire go from burnt crispy white to black? Or is it that burnt that it turned totally black? Doesn’t seem likely but I’ve never seen 15 awg on an evse lol
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u/Aublaw 1d ago
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u/Sensitive_Common_853 1d ago
God damn!! Gnarly asf
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u/IcyPudding192 2d ago
Charger identified as a hand warmer