Range Tripping GFCI (210.8, 555.53)

[LarryFine]

Temporarily replace the GFCI breaker with a standard breaker.

 

[mtnelect]

Temporarily replace the GFCI breaker with a standard breaker.

TIA 1748 would have given time for the task force resolved this problem.

Note: UL estimate of resolution 2028.

 

[brycenesbitt]

No, usually takes 3-5 minutes or more. The electrician who proposed this theory had not looked at the trip curves, he just noticed that the stove was supposed to be on a 50 amp breaker per manufacturer, but was pulling 54-55 amps as it was coming up to cooking temperature.

10% over for five minutes is a yawn on the trip curve.
--
How much access do you have to this site? Can you do some testing? Consider getting a Gen 3 Emporia meter, and hook to
all three phases. You can trivially graph the startup draw on all three legs: hot hot and neutral.
--
Why these appliances use neutral at all is still unnecessary, but it's likely there are a few mA going down the neutral to run the computer.

--
What model range?
Have you read the Massachusetts GFCI exception?
Have you run a new wire over the floor from the panel to a cowboy wired direct to the machine (skip the outlet) run just for testing?
Are you interested in a referral to technical folks at AHAM, the Association of Home Appliance Manufacturers? They're feeling the brunt of the GFCI revolution in terms of returns of equipment to stores, or so I've heard.

 

[tortuga]

5 milliamps to trip a GFCI at 120v comes out to 24,000 ohms of resistance, with field conditions to take into account. Is there a way I could try to measure the resistance to see if that is feasible in this case? Maybe from the case of the stove to a nearby grounded outlet?

UL943 Class-A GFCI's trip level is in the range 4 – 6mA.
My Ideal Sure Test tests GFCI's and gives you a readout of the test mA (usually around 7.3) and measures the time to trip in milliseconds, I'd recommend using one of those to test the trip time, all you need is a adapter cord to fit the range receptacle, I made an adapter with a 3- way switch so I can test each line-neutral of a range receptacle.

Another test I have done is with 30k ohm 3 Watt resistors wired to a pigtail.
I have two toggle switches to switch on the 2nd and 3rd 30k resistors in parallel.
I meter the leakage current, if the GFCI trips with the first resistor its too sensitive.
They make testers for 120V GFCI's but not 240V ones.

Is there a way I could try to measure the resistance to see if that is feasible in this case? Maybe from the case of the stove to a nearby grounded outlet?

I'd say measure the leakage current in miliamps with a known good meter and compare it to some test loads.

 

[brycenesbitt]

How the Commonwealth of MA handled all this

Emergency Amendment to Mass. Electrical Code (527 CMR 12.00)

 

[tortuga]

We removed and capped the equipment grounding conductor from the receptacle, and bonded the ground screw on the receptacle to the neutral screw on the receptacle (just for testing purposes).

It still trips the GFCI breaker. In this set-up, there is nowhere for leakage current to go except back on the neutral.

Can you post some photos of the test setup? What kind of box was it?

 

[mtnelect]

The problem is the design of the GFCI/AFCI ... The manufacturers didn't anticipate the new energy efficiency standards the Department of Energy has required, causing the use of electronics to meet their standards in appliances. See my post 122.

This industry will be stuck between the NEC and DOE until sometime in 2028 when the task force comes through with a solution. Explain this to your customers ... see if that helps !

 

[brycenesbitt]

Rule 11. Electrical installations that appear incompatible with GFCI protection as covered in 210.8 Exception of this Code, regardless of the code requirements in effect at the time when the permit as described in Rule 8 was issued, or when the installation was completed, shall be inspected by a qualified person. The inspection shall review all field elements of the branch- circuit equipment grounding return path, and the quality of any field-accessible cord connections if applicable. The inspection shall be documented, subject to audit by the Inspector of Wires, and inspected by him or her as deemed necessary. Installations of listed equipment that, under normal operating conditions, are found to be incompatible with GFCI protective devices as made available by the manufacturer of the circuit protection currently installed shall be excused from providing GFCI protection. If not connected to an individual branch circuit, incompatible equipment shall be directly wired or connected to a single receptacle, and the circuit shall be arranged so required GFCI protection is retained for the remaining outlets.

 

[mtnelect]

In California only the appliances certified can be installed, other states are in the process of passing similar requirements.

So, the industry stuck ... you have to install these appliances that will not work with GFCI/AFCI and the NEC say you have to install these devices for consumer protection.

 

[mtnelect]

I now put a disclaimer on my invoices ... One free service call to double check if my wiring was correct. The customer is then on their own.

Or what will it look like if a contractor wires a 200-unit complex and gets 200 consumer complaints of GFCI/AFCI tripping. How long can he stay in business ?

 

[curt swartz]

In California only the appliances certified can be installed, other states are in the process of passing similar requirements.

So, the industry stuck ... you have to install these appliances that will not work with GFCI/AFCI and the NEC say you have to install these devices for consumer protection.

You keep posting that no appliances will work on AFCI or GFCI which is NOT true. Some appliances have issues.

My Miele refrigerator has a 3 phase compressor connected to an AFCI breaker which has not tripped since it was first installed 4-1/2 years ago.

My Miele freezer has a 3 phase compressor connected to an AFCI breaker which has not tripped since it was first installed 4-1/2 years ago.

My LG refrigerator/freezer has a 3 phase compressor connected to an DF breaker which has not tripped since it was first installed 4-1/2 years ago.

Most of the issues with ranges and ovens are improper connection of the neutral/ground bond or moisture in the elements. The moisture issue can usually be resolved by running the unit on a standard breaker to dry out the elements. I agree this should not be necessary but there is a workaround that that manufacture need to figure out how to resolve before the appliance gets delivered.

Large motors on VFD's do have issues with GFCI's which is why they have held off on enforcing the GFCI requirements.

Commercial kitchen equipment has required GFCI protection for many years and not had many issues.

 

[mtnelect]

I agree that AFCI is not the problem, but since combination breakers are mostly used, I mention them.

 

[ramsy]

You keep posting that no appliances will work on AFCI or GFCI which is NOT true. Some appliances have issues.

Some Dual Function devices also filter electronic noise better than stand-alone GFCI's.

 

[NEC Inspector]

How much access do you have to this site? Can you do some testing?

Can you post some photos of the test setup? What kind of box was it?

Unfortunately, it was in someone's home, so we tested as described, but in the end we went with a non-GFCI breaker, approved the install, and I no longer have access to do any testing. I think it was one of the white fiberglass boxes? I don't have pictures.

We get this call from time to time, so each time it happens I try to get the electrician to test a new theory before going straight to the non-GFCI breaker. Normally, they will do one test because they are curious too, but in the end they need the project done and to move on, so we do one test and then I come up with a new theory/strategy and wait for the next one to test it on.

Have you read the Massachusetts GFCI exception?

Yeah, I know they have had quite a few problems with this issue. That is basically how we have had to handle it too, I just want to understand why they don't work and if there is a way around the problem that no one has thought of.

Are you interested in a referral to technical folks at AHAM, the Association of Home Appliance Manufacturers? They're feeling the brunt of the GFCI revolution in terms of returns of equipment to stores, or so I've heard.

Yes, absolutely, I would love to talk to them.

 

[NEC Inspector]

UL943 Class-A GFCI's trip level is in the range 4 – 6mA.
My Ideal Sure Test tests GFCI's and gives you a readout of the test mA (usually around 7.3) and measures the time to trip in milliseconds, I'd recommend using one of those to test the trip time, all you need is a adapter cord to fit the range receptacle, I made an adapter with a 3- way switch so I can test each line-neutral of a range receptacle.

Another test I have done is with 30k ohm 3 Watt resistors wired to a pigtail.
I have two toggle switches to switch on the 2nd and 3rd 30k resistors in parallel.
I meter the leakage current, if the GFCI trips with the first resistor its too sensitive.
They make testers for 120V GFCI's but not 240V ones.

I'd say measure the leakage current in miliamps with a known good meter and compare it to some test loads.

How much access do you have to this site? Can you do some testing? Consider getting a Gen 3 Emporia meter, and hook to
all three phases. You can trivially graph the startup draw on all three legs: hot hot and neutral.

These are good ideas, I will start plotting how to implement these on the next one. Thanks!

 

[Eddie702]

I posted a while back in June 24 of a new microwave installed on a 20-amp circuit I used a dual function breaker. The Microwave tripped the breaker twice within a month. No problems since July. Don't know if Microwaves have the same heating element issues but the problem seems to have gone away. Fingers crossed.

Of course, after it tripped the 2d time I picked up a standard 20-amp breaker and a gfci receptacle and was going to change those out now it looks like I won't have to. Time will tell.

 

[brycenesbitt]

Of course, after it tripped the 2d time I picked up a standard 20-amp breaker and a gfci receptacle and was going to change those out now it looks like I won't have to. Time will tell.

The underlying problem is we're asking two pieces of equipment from different vendors to
interoperate. That's hard.

 

[brycenesbitt]

These are good ideas, I will start plotting how to implement these on the next one. Thanks!

Emporia Home Energy Devices | EV Chargers, Energy Monitors, More

Shop Emporia's energy management products that help you save money by understanding and controlling your home energy usage.

shop.emporiaenergy.com

for the simple recording current meter. You'll need better kit to see current surges less than 1 second.