ddxact
DIY
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Hi,
I just wired a garage electric car charger (EVSE). The EVSE is configured for pulling 32 amp (240V) maximum, and directly connected. I am using 8-gauge copper THHN wires (2 with ground) run inside 3/4 EMT conduits about 30 feet, and then the rest with 8/2 romex in the basement for another 20 feet (total 50ft run), from the electric panel to the garage. In the electric panel I put 40 amp breaker. Somewhere in the middle of the run, I spliced the wire into an AC disconnect switch rated for 60A 240V (installed indoors, with aluminum lugs) for quick turn off of the EVSE when not in use. So far I am able to charge the car fine a few times, each charge about 6-7 hours sessions (overnight). The conduits and wires got just a little warm during use. However the AC disconnect switch gets quite much hotter, not the metal box, but the inside / plastic covers, especially during warmer ambient and humid days. One time, as soon as the charge was completed, I turned off the breaker, opened the switch, and touched the wires inside. Not burning hot, but quite hot to the touch, I'd say about 160-170F or so, almost not touchable. They look ok (not visibly burnt, yet). As far as I can tell, the lugs are quite tight. But they are aluminum, I heard aluminum heats up more than copper. Is this normal? Should I buy another disconnect switch with lugs that are made of copper (if that exist)? I am able to configure the EVSE to pull less current, let's say 24 amp, which is fine, but I'd rather be able to pull 32 amp if its ok.
Thanks for your help
I just wired a garage electric car charger (EVSE). The EVSE is configured for pulling 32 amp (240V) maximum, and directly connected. I am using 8-gauge copper THHN wires (2 with ground) run inside 3/4 EMT conduits about 30 feet, and then the rest with 8/2 romex in the basement for another 20 feet (total 50ft run), from the electric panel to the garage. In the electric panel I put 40 amp breaker. Somewhere in the middle of the run, I spliced the wire into an AC disconnect switch rated for 60A 240V (installed indoors, with aluminum lugs) for quick turn off of the EVSE when not in use. So far I am able to charge the car fine a few times, each charge about 6-7 hours sessions (overnight). The conduits and wires got just a little warm during use. However the AC disconnect switch gets quite much hotter, not the metal box, but the inside / plastic covers, especially during warmer ambient and humid days. One time, as soon as the charge was completed, I turned off the breaker, opened the switch, and touched the wires inside. Not burning hot, but quite hot to the touch, I'd say about 160-170F or so, almost not touchable. They look ok (not visibly burnt, yet). As far as I can tell, the lugs are quite tight. But they are aluminum, I heard aluminum heats up more than copper. Is this normal? Should I buy another disconnect switch with lugs that are made of copper (if that exist)? I am able to configure the EVSE to pull less current, let's say 24 amp, which is fine, but I'd rather be able to pull 32 amp if its ok.
Thanks for your help