NEMA 6-50 on 100A circuit permissible?

NEMA 6-50 on 100A circuit permissible?

I had a temp charging solution at home with a NEMA 6-50 on a 50 A circuit using the mobil Tesla charger. I am in the process of upgrading to the HPWC on a 100 A circuit. I though I could keep the NEMA 6-50 as a backup in case the HPWC has problems. The electrician tells me that this is not permissible in Los Angeles, because the NEMA 6-50 outlet is only rated for 50 A, while the new circuit is 100 A.

I would only use the NEMA 6-50 with the mobile charger, and that is limited to 40 A draw. So even if the NEMA 6-50 outlet is only rated 50A, it should be fine. Is this sound reasoning? Is this some electrical code thing? Has anybody in LADWP area had a HPWC with NEMA-flavor on same 100A circuit approved by inspectors?

vgrinshpun | May 7, 2013

Using NEMA 6-50 outlet connected to a 100A circuit will be a violation of National Electrical Code as 100A breaker for the HPWC circuit will NOT protect NEMA 6-50 outlet under low level fault conditions.

NEMA 6-50 outlet has to be on a separate circuit, protected by 50A breaker at the panel.

inverts | May 7, 2013

Thanks for the clarifications!