gfci afci protection

[tortuga]

From what I have heard, the ground fault protection in the charge controller is equipment level, not personnel level. Probably why they have a lot of nuisance tripping.

One way to look at that is look at the trip time, and amperage it takes to trigger the trip time;
for a standard 2 pole residential breaker to trip in 2 seconds it takes about 3 times the handle rating.
Say an appliance develops say a 2.6k ohm resistance fault to equipment ground, and say we don't want that lasting more than 2 seconds.
That fault would need to melt down to about 1.6 ohms to pull 3 X 50A or 150 Amps so you can trip a 2 pole 50A breaker in 2 seconds.
A standard off the shelf 30mA GFPE breaker must trip in 2 seconds at 150% of 30 miliamps (mA) or 45mA (0.045 Amps)
A GFCI breaker will trip 313ms with the same ground fault.
I can see the concern over regular breakers, with all the electronics in everything, but the difference between the GFCI and the GFPE breaker only 1.6 seconds and about 40ma of exposure during that time.
That means alot if your in a pool or lake but not much for 240V equipment.

 

[don_resqcapt19]

One way to look at that is look at the trip time, and amperage it takes to trigger the trip time;
for a standard 2 pole residential breaker to trip in 2 seconds it takes about 3 times the handle rating.
Say an appliance develops say a 2.6k ohm resistance fault to equipment ground, and say we don't want that lasting more than 2 seconds.
That fault would need to melt down to about 1.6 ohms to pull 3 X 50A or 150 Amps so you can trip a 2 pole 50A breaker in 2 seconds.
A standard off the shelf 30mA GFPE breaker must trip in 2 seconds at 150% of 30 miliamps (mA) or 45mA (0.045 Amps)
A GFCI breaker will trip 313ms with the same ground fault.
I can see the concern over regular breakers, with all the electronics in everything, but the difference between the GFCI and the GFPE breaker only 1.6 seconds and about 40ma of exposure during that time.
That means alot if your in a pool or lake but not much for 240V equipment.

There are no time trip requirements for GFPE in the product standards...it trips in what ever time the manufacture wants it to trip.

GFCIs have a maximum time to trip based on a formula in UL 943. That formula is: maximum permitted time to trip in seconds is equal to the quantity (20/fault current in milliamps) raised to the 1.43 power. That permits a maximum time to trip of 7.25 seconds for a 5 mA ground fault.

Most trip faster than the maximum permitted time, but some manufacturers have started putting in an intentional time delay for ground fault levels below 10 mA to help prevent nuisance tripping. If the ground fault goes away before the intentional time delay expires the GFCI does not open the circuit. If the fault is still there after the delay the device opens the circuit.

 

[retirede]

The first draft of the 2026 code 625.54 says all outlets that supply EVSE must have GFCI protection, so hard wiring wont change anything if that makes it through the process.

Is that limited to 150V to ground? Surely GFCI won’t be required for a 480V, 3 phase “outlet” connected to a 350KW DC charger?

 

[tortuga]

There are no time trip requirements for GFPE in the product standards...it trips in what ever time the manufacture wants it to trip.

My source says at least Siemens GFPE breakers are tested to UL 1053 Table 22.1 and UL 943 6.7.3

 

[tortuga]

GFCIs have a maximum time to trip based on a formula in UL 943. That formula is: maximum permitted time to trip in seconds is equal to the quantity (20/fault current in milliamps) raised to the 1.43 power. That permits a maximum time to trip of 7.25 seconds for a 5 mA ground fault.

Yes indeed thanks Don I credit you with helping me find that formula, that is the one I used to come up with the 313ms for the reference 45mA ground fault.

 

[tallgirl]

From what I have heard, the ground fault protection in the charge controller is equipment level, not personnel level. Probably why they have a lot of nuisance tripping.

That’s my understanding as well. I’ve had an EVSE for 10 or 11 years and this was a problem back then. Still a problem today.

 

[electrofelon]

Nothing 240V requires AFCI, with the exception of a MWBC.

I'm going to submit a PI saying that since AFCI is so great and proven, then there is no logical reason that they shouldn't be required on 240V circuits.

 

[don_resqcapt19]

Is that limited to 150V to ground? Surely GFCI won’t be required for a 480V, 3 phase “outlet” connected to a 350KW DC charger?

GFCIs are only for use on circuits that do not exceed 150 volts to ground.
I expect that the second draft will either delete the hardwired part of the rule and return to the 2023 language, or will take the path that CMP 17 took in Article 680, requiring the use of Special Purpose GFCIs (SPGFCI). Class C SPGFCIs are for circuits that do not exceed 300 volts to ground and Class D and E are for circuits that exceed 300 volts to ground.
The SPGFCIs are stand alone devices and not available as a breaker or receptacle. They also require an additional conductor between the SPGFCI and the protected equipment to verity that the equipment is connected to an EGC. If the device cannot verify that connection, it opens the circuit just like it would for a ground fault. The SPGFCIs also have a 20 mA trip point, but the time to trip formula is the same as I showed in post #22.

 

[don_resqcapt19]

I'm going to submit a PI saying that since AFCI is so great and proven, then there is no logical reason that they shouldn't be required on 240V circuits.

Have to change the scope of UL 1699 first. That specifies AFCI receptacles and breakers for up to 20 amps and with a supply voltage of 120.

 

[electrofelon]

Have to change the scope of UL 1699 first. That specifies AFCI receptacles and breakers for up to 20 amps and with a supply voltage of 120.

Why would that matter? New codes have come out when there isn't even a product standard for what the code says.

 

[don_resqcapt19]

My source says at least Siemens GFPE breakers are tested to UL 1053 Table 22.1 and UL 943 6.7.

I stand corrected on the GFPE trip time.

Not sure how anything in UL 943 would apply to a GFPE as the scope of UL 943 is Class A GFCIs.
Section 1.5 UL 943 says:

1.5 This Standard is intended to cover only Class A GFCI devices.

Section 6.7 contains the time to trip requirements for a Class A GFCI.