Burnt wire in the wall charger

[dilsherd]

I would wager this is the electrician's fault. The install looks super lazy. First of all, that wire between your panel and the charger should be in conduit (so should your 20A yellow romex to the outlet below the charger, but I digress). Those wires just running exposed would never pass inspection in my neck of the woods....electrical code requires wires to be protected from physical damage, and every inspector I've worked with basically requires anything in an exposed wall cavity (like you have in your garage) to be shielded or in conduit. Stuff up in the ceilings/rafters are generally ok without it.

Next, your wire just passes through the hole in the charger back, no clamp connector is present (something like this should be there: https://www.homedepot.com/p/Halex-1-in-Non-Metallic-NM-Twin-Screw-Clamp-Connector-90513/100113541). I would wager he also didn't put one on the panel either...this is a big no-no. The clamp provides strain relief and protects the connections (lets say you accidentally hit the cable one day while walking by with a suitcase or something...that is going to tug on the connector in the wall charger since nothing else is holding that wire in place anywhere. You NEED a clamp to ensure that tugs on the wire etc dont pull on the connectors in the charger OR in your panel).

It looks like your hot wire had a loose connection at the charger, and that led to high resistance at that point, and things got hot and melty. You can see that the screw terminal on your charger wire block for the hot wire is black, the green plastic around it is melty, and the circuit board below it looks black and burned. And the wire got hot and the sheathing got fried too. Frankly, your electrician saying it just needs a new wire is crazy...get a new electrician. The connector on your charger is fried, no electrician should be OK hooking up a new wire to a fried connector and thinking that is safe (and if he's just going to repeat his prior install without conduit or clamps, you're asking for more issues).

And FINALLY: He ran like 6 feet of cable. 6/3 cable (I assume that is what he ran based on your description) is $5 a foot from a big box store...he should be getting it at half that price or lower as an electrician (because he's buying in much larger quantities). Without conduit and clamps etc, that whole job is basically a 5 minute install. Not a great deal for $250.

Thank you. My electrician told me the cable is rated for 50A and that's probably what's caused this since I was pulling 48A.

I'm trying to see if he can fix this without charge - but sounds like I should just dump this electrician to avoid any other issues.

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[WSea]

Thank you. My electrician told me the cable is rated for 50A and that's probably what's caused this since I was pulling 48A.

I'm trying to see if he can fix this without charge - but sounds like I should just dump this electrician to avoid any other issues.

That and the NEC requires a derate for continuous use with EVSEs. As others have said, charging at the max 48amp requires 60amp breaker. 6/3 romex is 55amp max which doesn't include the derate

 

[dilsherd]

That and the NEC requires a derate for continuous use with EVSEs. As others have said, charging at the max 48amp requires 60amp breaker. 6/3 romex is 55amp max which doesn't include the derate

Can you explain what derate for continous use means? As in if 6/3 romex is 55A max -- it's derated capacity is closer to 48A for continous use?

 

[Dark-Fx]

I don't think changing the switches inside will reduce the maximum current without a reset from Rivian. I think those chargers are weird that way.

You can go down, but not back up.

 

[WSea]

Can you explain what derate for continous use means? As in if 6/3 romex is 55A max -- it's derated capacity is closer to 48A for continous use?

Clearing up Confusion over electric vehicles and smart charging (ampcontrol.io)

 

[Dark-Fx]

Can you explain what derate for continous use means? As in if 6/3 romex is 55A max -- it's derated capacity is closer to 48A for continous use?

NEC rules require derating to 80% for continuous use. 44A is the max you can put on a 6AWG Romex for continuous use. You're allowed to have it on a 60A breaker because 55A breakers generally don't exist. But it can only be wired to a single device that is set to 44A maximum.

Rivian doesn't have a 44A setting but some other EVSE manufacturers do.

 

[HaveBlue]

The issue is the insulation on 6/3 Romex not being HH rated is what Dark FX is saying. It's not just size that matters.

 

[SparkyR1t]

Can you explain what derate for continous use means? As in if 6/3 romex is 55A max -- it's derated capacity is closer to 48A for continous use?

When you run a continuous load for more than say 3 hours you derste the components or another way to say it is you increase the current carrying capacity of the circuit by 20% to allow for the heating that occurs when you push wiring with a continuous heavy amperage load. Same if you were installing an electric heater. If you check the wiring or circuit breaker after a vehicle has been charging for a few hours you will feel the heat which is normal.

 

[Nuclianba]

Thank you. My electrician told me the cable is rated for 50A and that's probably what's caused this since I was pulling 48A.

I'm trying to see if he can fix this without charge - but sounds like I should just dump this electrician to avoid any other issues.

I don't think this is the issue, the code is written around worst case conditions (like a really hot garage in the dead of summer) and the overheating occurred at the connection point in the wire block in the charger. The connection was bad. Bigger wire with a bad connection is still going to have this happen. He didn't torque the screws properly, or if he did since his install wasn't to code, the wire got knocked at some point, it pulled on the connector in the charger, and weakened the connection point. And as stated by others, the charger is now toast, do not trust it, it's damaged.

I would get a different (licensed) electrician over and get their thoughts. His or her reaction will tell you everything you need to know.

 

[Glembi2]

I would get a different (licensed) electrician over and get their thoughts. His or her reaction will tell you everything you need to know.

I second the motion.

While mention above in combination with other issues, the number one reason I would not talk to that electrician again is because of the lack of a strain release clamp on the incoming feed:

The charger either came with a black stain relief clamp like the one on the right and the electrician forgot to add it or the electrician should have supplied his own. Adding strain relief is wiring 101. For 120v lines, messing up can be bad but not as bad as messing up a 240v line.

Sure, the electrician could try to fix it but it is not worth the chance of damaging your house or truck.

And be sure you have a surge protector on your box. I didn’t and needed to replace both panels.

Finally, your city/county may be promoting EV charger installations and waiving permit fees. Getting a building inspector to check after fixing this issue should be cheap if not free

 

[WSea]

I second the motion.

While mention above in combination with other issues, the number one reason I would not talk to that electrician again is because of the lack of a strain release clamp on the incoming feed:

The charger either came with a black stain relief clamp like the one on the right and the electrician forgot to add it or the electrician should have supplied his own. Adding strain relief is wiring 101. For 120v lines, messing up can be bad but not as bad as messing up a 240v line.

Sure, the electrician could try to fix it but it is not worth the chance of damaging your house or truck.

And be sure you have a surge protector on your box. I didn’t and needed to replace both panels.

Finally, your city/county may be promoting EV charger installations and waiving permit fees. Getting a building inspector to check after fixing this issue should be cheap if not free

The whole install looks DIY...poorly

 

[Zoidz]

Thank you. My electrician told me the cable is rated for 50A and that's probably what's caused this since I was pulling 48A.

I'm trying to see if he can fix this without charge - but sounds like I should just dump this electrician to avoid any other issues.

You said previously that he installed a 70A breaker, so he knew he was creating an unsafe condition !?!?!?!?!? Or he never considered it??? WTAF??

 

[electruck]

When shopping for a new electrician, I highly recommend working with someone who has actual experience installing EVSEs. A lot of electricians are not yet familiar with these devices and the fact that they draw continuous loads. Think of it as seeing a medical specialist instead of a general practitioner.

 

[Electrified Outdoors]

Yeah a new electrician is in order. But that guy not only did a shoddy job he cost you an $800 charger in the process.

6/3 Romex is an interesting topic. Many electrician use it anyway. NM-B (aka Romex) which all you need for a hard wired charger is 6/2 is rated for 90C however code requires a derate to the 60C ampacity. Think hot exterior walls, attics, or crawl spaces. That's where the 55 amps comes from. They can round of the breaker to 60 amps but technically continuous load should be limited like was said to 44amps to meet the 80% rule.

4/2 or 4/3 Romex is not very easy to get either so many installs you will still see #6 Romex anyway.

I recommend THHN or MC #6 both of which are good. They are also easier to obtain than some #4 Romex.

 

[electruck]

I recommend THHN or MC #6 both of which are good. They are also easier to obtain than some #4 Romex.

Some EVSE will not even accept #4 Romex (although that doesn't stop some, I've seen a few cringe stories of folks trimming strands to make it work ?).

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