Wall charger wire gauge question

[R1S88]

I'm having a Rivian Wall Charger installed in the garage of a high rise apartment building. It's quite a long run and the electrician wants to run copper 4 awg wire to reduce voltage drop. Question - will he have to drop it down to 6 awg near the charger in order to fit the terminals of the Rivian Wall Charger? Or, can the 4 awg work? Thanks,

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[Polar]

He’ll have to drop it down.

 

[R1S88]

He’ll have to drop it down.

That's what I figured - thanks for the response

 

[SANZC02]

I'm having a Rivian Wall Charger installed in the garage of a high rise apartment building. It's quite a long run and the electrician wants to run copper 4 awg wire to reduce voltage drop. Question - will he have to drop it down to 6 awg near the charger in order to fit the terminals of the Rivian Wall Charger? Or, can the 4 awg work? Thanks,

Just curious how long is the run?

 

[Dark-Fx]

Running 6 and limiting to 40A might be an option to consider as well, depending on how that changes the cost.

 

[R1S88]

Just curious how long is the run?

About 80 feet

 

[R1S88]

Running 6 and limiting to 40A might be an option to consider as well, depending on how that changes the cost.

Thanks for the response - I'm only trying to maximize charging speed and not worrying about cost. Correct me if I'm wrong, but this would not allow charging at the full capability.

 

[Zoidz]

Your electrician isn't wrong, he's doing the right thing by considering voltage drop. But in your case it's not significant. #6 at 1.42% voltage drop is still well under NEC maximum of 3%. Considering that #4 costs more and if done right, he needs provide approved transition from #4 to #6 which will also add to the cost.

I would measure the line voltage at the panel. It may be higher or lower than than 240v. I'd just go with #6 as long as the line voltage is at least 238 volts at the panel.

 

[R1S88]

Your electrician isn't wrong, he's doing the right thing by considering voltage drop. But in your case it's not significant. #6 at 1.42% voltage drop is still well under NEC maximum of 3%. Considering that #4 costs more and if done right, he needs provide approved transition from #4 to #6 which will also add to the cost.

I would measure the line voltage at the panel. It may be higher or lower than than 240v. I'd just go with #6 as long as the line voltage is at least 238 volts at the panel.

very helpful - thanks

 

[beatle]

I did 50ft 6awg Romex for my first Tesla UWC since it was run in-wall. I did 8awg in conduit to the second one about 15 feet away. These share a 50A breaker and are set at 40A charge speed. 4awg is definitely not necessary.

 

[RivianRiverRat]

Are you in a jurisdiction that requires a permit and inspection for the work?
If so check with them on code requirements

 

[Eeyore]

Your electrician isn't wrong, he's doing the right thing by considering voltage drop. But in your case it's not significant. #6 at 1.42% voltage drop is still well under NEC maximum of 3%. Considering that #4 costs more and if done right, he needs provide approved transition from #4 to #6 which will also add to the cost.

I would measure the line voltage at the panel. It may be higher or lower than than 240v. I'd just go with #6 as long as the line voltage is at least 238 volts at the panel.

I agree with this response. Well done.

 

[Time2Roll]

I agree with #6. Going oversize does nothing except add unneeded cost and two more connections that could have issues.

 

[Supratachophobia]

About 80 feet

I don't think that's too far to be honest. I'm pushing 2 Tesla HPWC and their runs are 60 and 75ft respectively. Both have 6-3 with the longer run going on 12 years or so.

You can always run the 4 gauge to a disconnect or sub panel right before the charger and then drop to 6-2 at the breaker or disconnect.

 

[R1S88]

Update: I was given a more accurate measurement and it’s actually 130 feet. I suspect the answer is still to go with 6 awg, but thought I would ask the experts here to be sure. Thanks!

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