EV Charger: #8 Romex on 50a Breaker

[kwired]

Thanks Wayne. That's the answer I've been given most often- that you are supposed to intertwine the two tests together. I just can't find where the Code says to do that. It also seems like doing so contradicts the definition of allowable ampacity, which says already clarifies that it's talking about a continuous circuit.

You can account for the circuit being continuous by reducing the ampacity of the cable (40a actual current =< 40a adjusted ampacity) or increasing the current of the load (50a calculated current =< 50a actual capacity), but why would you account for it twice?

You are not accounting twice. If a 40 amp load is continuous then 210.19 is saying the minimum ampacity of conductor you use must be 125% of 40.

210.20 says basically the same thing but applies to overcurrent protection instead of conductor ampacity.

Somewhere in art 240 the two are also tied together because the conductor must be protected at no more than it's rated ampacity.

The allowance for higher overcurrent goes through 240.3 and on to other sections mentioned there. Things like motors, AC and refrigeration, capacitors, etc. though those all still typically require 125% of actual load for minimum conductor ampacity.

 

[letgomywago]

Are you buying this regularly? From where?

Yes fairly regularly. North Coast in WA has it often in cut lengths.

 

[Birken Vogt]

I noticed Platt seems to sell it in cuts up there too, but nowhere else.

 

[letgomywago]

I noticed Platt seems to sell it in cuts up there too, but nowhere else.

Order a 150ft coil it's not a bad price

 

[Birken Vogt]

I'm still at a loss here, Tortuga was ordering 6/3 Cu SER but we started talking about EV chargers, which should only need 6/2, or did it switch to ranges?

@letgomywago is it 6/2 SEU or 6/3 SER you order regularly?

 

[letgomywago]

I'm still at a loss here, Tortuga was ordering 6/3 Cu SER but we started talking about EV chargers, which should only need 6/2, or did it switch to ranges?

@letgomywago is it 6/2 SEU or 6/3 SER you order regularly?

SEU
6-6-8

 

[tortuga]

Well I just looked at the code again and I need to retract my earlier comment about 8/3 tray cable, even if its rated 'joist pull' you are limited to the 60C column [336.10(9)], the only exception is a generator which is strange, you'd think if its good for 75C terminations the type of equipment would not matter.