I'm trying to help a friend who just bought an EV and wants to install a 48 amp charger (EVSE) for it. He's installed 120vac circuits before, but I think this is a little over his head. He wants to mount it on the edge of a deck, at a location that is about 15ft distant from a corner of the house where the main load center is located in an interior wall; thus some of the wire will be in a wet location.
The main problem is that an EVSE is considered a continuous load, and therefore the circuit must be up-sized by 25%, so a 60 amp circuit is required. Some people are under the misapprehension that 6awg NM-B (Romex) can be used for a 60 amp circuit, but this is false - see the attached ampacity table and recall that the 60-degreeC column must be used for NM-B (and UF-B). It can be used for 55 amp circuits, and the "step up" rule allows 60 amp breakers to be used on 55 amp circuits. Hence the confusion. So something else is needed.
One option is to run THWN in conduit. The problem with this is that it'd be pretty tough to run conduit up to the panel. Perhaps we could run 4awg Romex down to a junction box, and then transition to conduit with 6awg THWN. Another option would be to use armored cable (type MC), but it'd need to be the type that is sheathed in a PVC jacket (for water-resistance). This is called Teck90 cable: https://nassaunationalcable.com/pro...QRzm70dpv9KqQps6H-JOK1bJEItgghQBoC1OIQAvD_BwE
It's pretty damn expensive, and it requires special terminations (at least at the end that's exposed to weather) and those appear even more expensive.
I suppose we could just use 4awg UF-B, except I'm not sure that even exists, and it'd be a PITA to work with if it did.
So I'm wondering if there's something else I'm not thinking of.
My inclination is to tell him to exchange the 48 amp EVSE for a 40 amp one, and just use 6awg UF-B the whole way. My household has not one, but two, EVs and we are perfectly content with a 40 amp EVSE.
The main problem is that an EVSE is considered a continuous load, and therefore the circuit must be up-sized by 25%, so a 60 amp circuit is required. Some people are under the misapprehension that 6awg NM-B (Romex) can be used for a 60 amp circuit, but this is false - see the attached ampacity table and recall that the 60-degreeC column must be used for NM-B (and UF-B). It can be used for 55 amp circuits, and the "step up" rule allows 60 amp breakers to be used on 55 amp circuits. Hence the confusion. So something else is needed.
One option is to run THWN in conduit. The problem with this is that it'd be pretty tough to run conduit up to the panel. Perhaps we could run 4awg Romex down to a junction box, and then transition to conduit with 6awg THWN. Another option would be to use armored cable (type MC), but it'd need to be the type that is sheathed in a PVC jacket (for water-resistance). This is called Teck90 cable: https://nassaunationalcable.com/pro...QRzm70dpv9KqQps6H-JOK1bJEItgghQBoC1OIQAvD_BwE
It's pretty damn expensive, and it requires special terminations (at least at the end that's exposed to weather) and those appear even more expensive.
I suppose we could just use 4awg UF-B, except I'm not sure that even exists, and it'd be a PITA to work with if it did.
So I'm wondering if there's something else I'm not thinking of.
My inclination is to tell him to exchange the 48 amp EVSE for a 40 amp one, and just use 6awg UF-B the whole way. My household has not one, but two, EVs and we are perfectly content with a 40 amp EVSE.
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