No equipment is 100% efficient. Assuming you circuit is a measly 206 volts, you are putting 6.6 kW through your EVSE. If the EVSE is 98.5% efficient it will get as hot as a 100 watt incandescent bulb.I haven,t put a thermometer on it ,but it can be held onto .I,m using a Siemens versichage plugged into a wall outlet I installed with 8 gauge stranded wiring in an 8' long conduit.After a hour charge this morning I felt the most heat at the wall plug ,followed buy the car plug cable ,some warmth all the way to and including the circuit breaker, very little else drawing power in the houes,This was all newly installed December 2019.It has been exceptionally hot hear in Calif. even at night in the garage where it's charged .I haven't seen this kinda heat wave with the load of a 32 amp system .Haven't used the quick charge option lately ,using it now might be a good cord heating test .With the heat concentrated at the wall plug supplied with the charger, I'm suspecting its inadequate,it could be omited with a hardwire install.
I believe the wire type has some impact, so I'll quote for THWN, which is I believe a more commonly used cable. The charts show 10 gauge wire is good for 35 amps, with 8 gauge jumping to 50. I used 8 gauge to wire my daughter's 40 amp Juicebox, even thought her PHEV only draws 32 amps max. I believe if you use separate wires within conduit you get a higher rating than using a bundled wire. The advantage to a UF cable is that conduit isn't necessary, and in some cases can be direct buried underground. But with UF 10 gauge is only rated for 30 amps and 8 gauge for 40. The larger the wire size, the greater the difference between the two types of cable capacity. And all these numbers are based on copper wire. Switch to aluminum and the current rating drops even lower.Can anyone weigh in on the required cable thickness for 32amp+ nema 14-50 charging? My Chinese charger has a TUV approved cable but its only 3*2.5mm²+2*0.5mm² which seems small compared to competitors. Plug head gets up to 130F. Cable right off the plug head gets up to 150F
Yeah it seems like a bunch of competitors use 3*6mm²+2*0.5mm² for 32amps and over. I'm trying to figure out if I'm comparing apples to apples.....I have to think that using cable that is too small from the plug back would cause some heat issuesI believe the wire type has some impact, so I'll quote for THWN, which is I believe a more commonly used cable. The charts show 10 gauge wire is good for 35 amps, with 8 gauge jumping to 50. I used 8 gauge to wire my daughter's 40 amp Juicebox, even thought her PHEV only draws 32 amps max. I believe if you use separate wires within conduit you get a higher rating than using a bundled wire. The advantage to a UF cable is that conduit isn't necessary, and in some cases can be direct buried underground. But with UF 10 gauge is only rated for 30 amps and 8 gauge for 40. The larger the wire size, the greater the difference between the two types of cable capacity. And all these numbers are based on copper wire. Switch to aluminum and the current rating drops even lower.
Absolutely correct. Too small a cable increases resistance, which generates heat, which is a bad thing. Oversizing electrical cable never hurts, but it does increase cost, so try not to go overboard.I have to think that using cable that is too small from the plug back would cause some heat issues