Is GFCI necessary?

[BryCola]

Some great information in this thread. I'm glad I asked. Thanks for all of the replies. I think I'm comfortable without GFCI. So my electrician actually saved me a few bucks.

Sponsored

 

[Mach-Lee]

The reason the code now requires GFCI even if the EVSE already has one, it because if a person comes into contact with voltage between the outlet and the EVSE, the the EVSE will not provide protection. "You don't need it" as long as there is no fault before the EVSE!

It's also a myth that cascaded GFCIs will nuisance trip.

I think the issue is more with the difference in fault currents between the two devices. A typical EVSE will have a 20 mA fault threshold but a Class A breaker will have a 5 mA threshold. During normal use with a longer cord or wet conditions, it's possible that the ground current will exceed 5 mA for brief periods and trip the breaker even when nothing is wrong. Sometimes 5 mA is just too sensitive for certain situations.

I called Grizzl-E, they were having some issues with units going into fault or tripping GFCI breakers on startup, this was corrected with a mid-July 2021 firmware update. Units made or updated after this time shouldn't have that issue with GFCI breakers anymore. The fault current is 20-25 mA on their EVSEs.

Even with the update, the sensitivity issue with the breaker remains. Tripping issues are probably rare, but could be very annoying if you are one of the unlucky people to run into repeated issues, in that case you'd probably have to call and ask an electrician to replace the GFCI breaker with a standard one. Not good when you have to go to work and see your car hasn't charged enough because the breaker tripped overnight.

My personal opinion is that a 5 mA fault current is too sensitive, the threshold for 240V GFCI should really be raised up to 20 mA to virtually eliminate nuisance trips, while still preventing electrocution. Hopefully they fix this in the 2023 NEC. Many states have had to roll back the 240V GFCI rules in the 2017+ NEC due to nuisance tripping on ranges and outdoor A/C units (see article below). My state has also exempted these provisions from the adopted 2020 NEC for similar reasons. My final recommendation is to skip the GFCI breaker for now unless your code requires it. This will also save you some money on the install.

Articles about new GFCI rules:
New Electrical Code Requirement Causing Big Problems in the Field
Another Issue with the 2020 Electrical Code: Ranges Tripping on GFCIs

 

[Maquis]

I think the issue is more with the difference in fault currents between the two devices. A typical EVSE will have a 20 mA fault threshold but a Class A breaker will have a 5 mA threshold. During normal use with a longer cord or wet conditions, it's possible that the ground current will exceed 5 mA for brief periods and trip the breaker even when nothing is wrong. Sometimes 5 mA is just too sensitive for certain situations.

I called Grizzl-E, they were having some issues with units going into fault or tripping GFCI breakers on startup, this was corrected with a mid-July 2021 firmware update. Units made or updated after this time shouldn't have that issue with GFCI breakers anymore. The fault current is 20-25 mA on their EVSEs.

Even with the update, the sensitivity issue with the breaker remains. Tripping issues are probably rare, but could be very annoying if you are one of the unlucky people to run into repeated issues, in that case you'd probably have to call and ask an electrician to replace the GFCI breaker with a standard one. Not good when you have to go to work and see your car hasn't charged enough because the breaker tripped overnight.

My personal opinion is that a 5 mA fault current is too sensitive, the threshold for 240V GFCI should really be raised up to 20 mA to virtually eliminate nuisance trips, while still preventing electrocution. Hopefully they fix this in the 2023 NEC. Many states have had to roll back the 240V GFCI rules in the 2017+ NEC due to nuisance tripping on ranges and outdoor A/C units (see article below). My state has also exempted these provisions from the adopted 2020 NEC for similar reasons. My final recommendation is to skip the GFCI breaker for now unless your code requires it. This will also save you some money on the install.

Articles about new GFCI rules:
New Electrical Code Requirement Causing Big Problems in the Field
Another Issue with the 2020 Electrical Code: Ranges Tripping on GFCIs

There are, indeed, some nuisance issues with GFCIs. The cause is devices with more leakage to ground than the GFCI is designed to detect. GFCIs themselves do not have leakage to ground and thus will not cause other GFCIs to trip. I was involved in the industry when GFCIs were introduced!

Probably the most annoying thing about seriesed GFCIs is that it's often a crapshoot as to which one trips in event of a fault. Murphy's law says it will be the one farthest away (breaker in the basement panel)!

The 20mA threshold (Class B) is relatively new to UL - previously, GFCIs were 5mA, and there were GFPEs with a 30 mA threshold. It is too bad these groups (UL & NFPA) don't coordinate. Even if UL & NFPA were in sync, we still have the problem of timely code adoption by jurisdiction. We're still on the 2008 in Illinois, unless a locality has their own adoption - I know Chicago does.

 

[TheVirtualTim]

So I got the answer on the GFCI and the Ford Mobile Charger...

The Ford Mobile Charger DOES have built-in GFCI. This only protects you if there is a problem which occurs *after* the EVSE block on the charger. You are not protected if there is a problem between the service panel and the outlet. The recommendation for a GFCI breaker is meant to protect you if there is a problem between the service panel and the outlet ... especially if the outlet is installed outdoors.

The reason the Ford Connected Charge Station doesn't recommend a GFCI breaker is because it is only meant for a direct-wire (no plug-in receptacle) and it has it's own GFCI ... so it's not like you'd ever connect anything else to the circuit that powers It.

Sponsored