Refrigerator / Freezers on GFCI's

[daveselectric]

I have been told by the Leciton tech support staff that a refrigerator motor is to strong for GFCI protection. The reason given is that the return thru the neutral is not equal to the flow thru the hot causing an iinbalance and tripping. The NEC 08 requires that unfinished basements and garage receptacles be GFCI protected. This problem can occour with a sump pump. Any ideas on how to solve this problem.

 

[charlie b]

I have been told by the Leciton tech support staff that a refrigerator motor is too strong for GFCI protection.

That is pure nonsense. ?Too strong?? What on earth can that mean?

The reason given is that the return thru the neutral is not equal to the flow thru the hot causing an imbalance and tripping.

That violates the laws of physics.

Any ideas on how to solve this problem.

Install the GFCI devices where required, and recommend to the owner that they buy appliances and pumps that do not have internal faults. That sounds facetious, I know. But if a appliance trips a GFCI, then there is a problem with the appliance.

 

[mdshunk]

I have been told by the Leciton tech support staff that a refrigerator motor is to strong for GFCI protection.

Hogwash.

As a refrigerator ages, insulation breakdown occurs. The breakdown is quite measurable, and is generally in the windings of the hermetic motor-compressor. Megohm readings at the appliance's attachment plug, from hot to ground (or neutral to ground) prove this beyond doubt.

If the GFCI trips when a refrigerator is plugged into it, the GFCI did its job.

 

[ceb58]

The reason given is that the return thru the neutral is not equal to the flow thru the hot causing an iinbalance and tripping.

That's as good as any excuse I've heard to try to cover your butt. If you have a refg. compressor "taking in" 8 amps, then if their is no moisture in the system, the windings have not broken down, then you will "return 8 amps. The GFCI will not see a imbalance and be happy but if their is moisture or the windings have broken down to a point that they let a small amount leak to ground the GFCI will see that and not be happy any more.
The same holds for a true for a sump pump if the pump is tripping a GFCI then more than likely you are getting moisture in the motor. I have lift pumps that have been running for years on GFIC outdoors in W/P boxes and have not had any problems. Now, with that said the pumps I used did not come from a local home improvement store they were a higher end, better quality pump.

 

[iwire]

I agree with Charlie and Marc.

I have been told by the Leciton tech support staff that a refrigerator motor is to strong for GFCI protection.

That is odd as pool pump motors work fine on GFCIs and on construction sites 15 amp chop saws work fine on GFCIs.

The reason given is that the return thru the neutral is not equal to the flow thru the hot causing an imbalance and tripping.

As Charlie pointed out that is imposable unless as Marc pointed out there is insulation breakdown in the motor or in the electric defrost elements.

The NEC 08 requires that unfinished basements and garage receptacles be GFCI protected. This problem can occur with a sump pump. Any ideas on how to solve this problem.

As an electrician there is nothing to be solved, the NEC exceptions have been taken away and you must install GFCIs. If the appliance trips the GFCI there is a problem with the appliance.

It happens my own sump pump was on a GFCI for a few years and it runs many times an hour during rain. Never tripped the GFCI, if it did that would be an early warning sign to buy a new pump.

 

[Jim W in Tampa]

The guy was looking for an excuse to not fix it.No reason they cant run on them other than they have leakage.

 

[brother]

Hogwash.

As a refrigerator ages, insulation breakdown occurs. The breakdown is quite measurable, and is generally in the windings of the hermetic motor-compressor. Megohm readings at the appliance's attachment plug, from hot to ground (or neutral to ground) prove this beyond doubt.

If the GFCI trips when a refrigerator is plugged into it, the GFCI did its job.

Marc, when you megger an appliance from hot to ground, neutral to ground or hot to neutral, what readings should you get to let you know its bad?

 

[mdshunk]

Marc, when you megger an appliance from hot to ground, neutral to ground or hot to neutral, what readings should you get to let you know its bad?

Depends mostly on my mood and the phase of the moon. The readings are either really good (150 meg and higher) or really bad (20 meg and lower). Not so much in between. I'm totally comfortable comdemning equipment that megs 20 or less.

 

[brother]

Depends mostly on my mood and the phase of the moon. The readings are either really good (150 meg and higher) or really bad (20 meg and lower). Not so much in between. I'm totally comfortable comdemning equipment that megs 20 or less.

ok so there is no rule of thumb on appliances?? So when you megg a motor hot to neutral knowing it will pass thru the coil, it will have to be above 20 meggs to pass?? seems that the hot and neutral megg would naturally be lower (because of the coil) than the hot to ground megg or neutral to ground, or hot to ground.

 

[tom baker]

Minimum resistance is 1 meg ohm plus operating voltage.
Do the math with 120V, what resistance will it take to get 5 mA?
99.9% of the time if a GFCI trips its doing its job. It trips between 4-6 mA, about 15 will give you a shock and 30 is enough to kill. I have seen sump pumps with dead shorts - causing a GFCI to trip. Was that a bad GFCI?

Thousands of lives have been saved with GFCIs. They cost less than a movie ticket.

 

[mdshunk]

ok so there is no rule of thumb on appliances?? So when you megg a motor hot to neutral knowing it will pass thru the coil, it will have to be above 20 meggs to pass?? seems that the hot and neutral megg would naturally be lower (because of the coil) than the hot to ground megg or neutral to ground, or hot to ground.

Never meg hot to neutral unless you want to turn a functional appliance into a non-functional appliance.

 

[mdshunk]

Just from a pure math standpoint, you can be in pretty low megohms and not trip a GFCI. I guess around .025 to .03 megohms to trip a GFCI. However, if you're down less than 20 megohms, something pretty serious has happened to that appliance. All it might take is a little bit of vibration to turn that 18 meg into .5 meg. I guess it takes megging a bunch of appliances to realize that you'll either get really high readings or really low readings. It is only those apliance where you'll measure really low readings that will occasionally trip the GFCI. Pay less attention to what the actual reading is. It's only important to note that it's in that lower percentile group.

 

[Pierre C Belarge]

Never meg hot to neutral unless you want to turn a functional appliance into a non-functional appliance.

Just wanted to emphasize this statement.

It is the reason that all loads are removed from a circuit when you are megging after a fire or water damage.
You may do more damage than the fire or water if you megger across the phase and neutral conductors.

 

[goldstar]

As an electrician there is nothing to be solved, the NEC exceptions have been taken away and you must install GFCIs. If the appliance trips the GFCI there is a problem with the appliance.

In addition to whatever personal qualities you've developed over the years you'll now have to become an exceptional salesman. As far as homeowners are concerned "This nuisance tripping has never happened before and I've lost all the food in the refrigerator" will be the normal complaint. You'll be 100% correct in installing that GFI in an unfinished basement or garage and you'll have to sell your customer on the fact that this is an NEC requirement and the problem is with their appliance, but you can be rest assured that this receptacle will soon be changed out either by the homeowner or some hack looking to make a fast buck. Hopefully they'll call you back for repeat business.

It happens my own sump pump was on a GFCI for a few years and it runs many times an hour during rain. Never tripped the GFCI, if it did that would be an early warning sign to buy a new pump.

I'm not saying you're wrong. I can read the code book as well as you can but you'd be lucky to get an early warning if your sump pump is going bad. The pump doesn't come with an early warning light or meter so you have no way of knowing exactly when it's going to break down with a GF problem. In your honest opinion would you truly be concerned if it developed a GF problem during a hurricane ? Would you have a back-up pump in that event ? Would you, in all likelyhood, be home when it started to break down ?

Sorry, just playing devil's advocate.

 

[mdshunk]

When you offer that the alternative to a fridge of spoiled food might be a fire gutted home, the explanation is much easier .

 

[JohnJ0906]

When you offer that the alternative to a fridge of spoiled food might be a fire gutted home, the explanation is much easier .

Or a shock from touching the frame....

 

[mdshunk]

Or a shock from touching the frame....

or that!

I was involved with one house fire rewire job where Liberty Mutual deterined the cause to be an old basement fridge that failed somehow or another, so that's why that popped in my head.

 

[iwire]

You'll be 100% correct in installing that GFI in an unfinished basement or garage and you'll have to sell your customer on the fact that this is an NEC requirement

I don't have to sell on it I can show it to them, if they want to pass inspection it has to be there.

but you can be rest assured that this receptacle will soon be changed out either by the homeowner or some hack looking to make a fast buck.

Not my concern at all, I worry about the work I do, what the HO decides to do after I am gone is up to them.

but you'd be lucky to get an early warning if your sump pump is going bad. The pump doesn't come with an early warning light or meter so you have no way of knowing exactly when it's going to break down with a GF problem.

The first time the pump trips the GFCI is the warning, simply reseting the GFCI and ignoring the issue is a poor choice.

IF your sump pump is that important then you better not be relying on a constant stream of power from the receptacle unless you have it on a UPS / generator setup. Power outages happen.

Would you have a back-up pump in that event ?

I DO have a brand new back up sump pump on the shelf, waiting till it breaks down during a storm only to find the stores out of stock is not something I want.

I also have a generator on hand to run it. In a storm my basement will flood without the sump pump.

Would you, in all likelihood, be home when it started to break down ?

No, not likely, which is a problem but would I likely be home during a power company outage?

Sorry, just playing devil's advocate.

Nothing to be sorry about.

 

[goldstar]

When you offer that the alternative to a fridge of spoiled food might be a fire gutted home, the explanation is much easier .

Can you make the same sales pitch for a flooded basement ? (And you can't use Bob (iwire) as your typical sample customer. He has every contingency for failure covered. You'll have to pick Joe Homeowner as your example.)

It's one thing for us to be standing in front of a homeowner who is cleaning out their refer after a GFI trip trying to convince them that they are much better off losing their food than their house (although I don't know how we got to a burnt down house scenario from a GF problem). It's quite another to be standing outside a homeowher's house while the fire dept. is there pumping out their basement because their pump tripped the GFI. Of course, if you are Bob (iwire's) neighbor he'd be outside lecturing you on why you didn't have a back-up pump (without a GF problem) or generator in case of a power failure.

I'm not trying to be a smart a** about this but in addition to our installation and troubleshooting abilities we're now going to have to become better salesmen. The enforcement of this code section is equivilent to telling the general public that anyone buying a new car from this date forward will have to by a hybrid. Anything they were accustomed to before is no longer available. A big pill to swallow.

 

[soccercomplexity]

I agree with Charlie and Marc.



That is odd as pool pump motors work fine on GFCIs and on construction sites 15 amp chop saws work fine on GFCIs.




As Charlie pointed out that is imposable unless as Marc pointed out there is insulation breakdown in the motor or in the electric defrost elements.




As an electrician there is nothing to be solved, the NEC exceptions have been taken away and you must install GFCIs. If the appliance trips the GFCI there is a problem with the appliance.

It happens my own sump pump was on a GFCI for a few years and it runs many times an hour during rain. Never tripped the GFCI, if it did that would be an early warning sign to buy a new pump.

An early warning sign requires someone to see it. My sump pump developed leakage greater than the 5 mA required and the GFCI did it's job. $2700 later in water recovery of our basement, since we were out of town, and I replaced the GFCI with a single receptacle dedicated outlet for the sump pump. It was my understanding at the time, 2005, that this was within the exceptions allowed by the NEC.

If not, I'd like to know.

thanks,
david