GFCI recep spitting fire

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dicklaxt

Senior Member
I plugged a freezer into a GFCI and sparks/arcing flew before insertion was complete.I immediately pulled it clear.I then looked to see if the freezer was on ,,,naturally it was,turned it off,reinserted the plug,turned on the freezer and everything is fine... I think.

The question is,,,,,,is this GFCI now just a standard receptacle( with blown electronic's) or did it ride thru the storm?.............any of you ever experienced this,I never had one do that before.I think I'll replace it just to be safe.

BTW that was quite a Christmas Day,a 76 year old man with COPD (24/7 oxygen)and a 72 year old woman swapping refrigerators out with out an appliance dolly,no rental places open.

dick
 
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kwired

Electron manager
Location
NE Nebraska
It was probably a good idea to replace it, although if the test button still trips it, it should still be functional.

The test button actually does introduce unbalanced current at the 4-6 mA range across the sensing coil, and if the sensing circuitry is working it responds to what it sees as a real fault condition. Pressing the test button puts current through a resistor that is connected from one line terminal to the opposing load terminal - this simulates a fault condition by truly placing unbalanced current thru the sensing coil and it will respond if it is working correctly.
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
besides the "test" button you can also test the GFCI with a wiggy or a just 60W light bulb to see if trips.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
The test button actually does introduce unbalanced current at the 4-6 mA range across the sensing coil, and if the sensing circuitry is working it responds to what it sees as a real fault condition. Pressing the test button puts current through a resistor that is connected from one line terminal to the opposing load terminal - this simulates a fault condition by truly placing unbalanced current thru the sensing coil and it will respond if it is working correctly.

I have to disagree with that. All the test button does is trip the mechanism.

If you shut the power off feeding a GFCI and push the test button it will still trip. I can even be totally not wired and in the box. A properly functioning GFCI will not re-set without power, but will trip with the test button no matter if there is current or not.

Think about this. How can the test button make for an unbalanced current if there is no grounding conductor or other 'third path' back to the source?
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
I have to disagree with that. All the test button does is trip the mechanism.

If you shut the power off feeding a GFCI and push the test button it will still trip. I can even be totally not wired and in the box. A properly functioning GFCI will not re-set without power, but will trip with the test button no matter if there is current or not.

Think about this. How can the test button make for an unbalanced current if there is no grounding conductor or other 'third path' back to the source?

I belive a true test is a load across the hot and a grounded body. Even though the manufacturer suggested way of testing the GFCI is the test button.
 

LEO2854

Esteemed Member
Location
Ma
I plugged a freezer into a GFCI and sparks/arcing flew before insertion was complete.I immediately pulled it clear.I then looked to see if the freezer was on ,,,naturally it was,turned it off,reinserted the plug,turned on the freezer and everything is fine... I think.

The question is,,,,,,is this GFCI now just a standard receptacle( with blown electronic's) or did it ride thru the storm?.............any of you ever experienced this,I never had one do that before.I think I'll replace it just to be safe.

BTW that was quite a Christmas Day,a 76 year old man with COPD (24/7 oxygen)and a 72 year old woman swapping refrigerators out with out an appliance dolly,no rental places open.

dick
Well that is what happens when you plug in an appliance under load and the contacts on the receptacle are probably worn out which will magnified what you saw so I would change out the GFCI for a new one.:thumbsup:
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
I belive a true test is a load across the hot and a grounded body. Even though the manufacturer suggested way of testing the GFCI is the test button.

I agree. All the test button does is it makes sure stuff moves to and fro as designed. It really does not test the ability to detect and interrupt a fault. It should be called an exercise button because using it regularly will keep the moving parts from sticking.

I made up an adapter so I can use an external tester for GFCI's. It's just a 2 to 3 prong adapter with a piece of wire attached to the place the ground screw is supposed to go. Then, I ground the wire, put the adapter ahead of the push button tester and it works like it would in a standard properly grounded three prong outlet.
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
Well that is what happens when you plug in an appliance under load and the contacts on the receptacle are probably worn out which will magnified what you saw so I would change out the GFCI for a new one.:thumbsup:

unless if OP was trying to reset the GFCI while the appliance was plugged in, otherwise the GFCI is always engaged.
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
Well you are wrong. And, your actions are non-compliant with the device's UL Listing.

I may be wrong because my way of testing is against the UL listing instructions but it works every time. If under my test the GFCI doesn't trip then it is a bad GFCI. I change the unit.
 

dicklaxt

Senior Member
Just curious, what kind of freezer has an on and off switch?

I have seen an off position in the thermostat, but not a separate switch, and really wouldn't trust it as a load disconnecting means.


It was the off position on the t stat
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
I may be wrong because my way of testing is against the UL listing instructions but it works every time. If under my test the GFCI doesn't trip then it is a bad GFCI. I change the unit.

How many devices have you changed, only to find out the problem was with the ground?

IMO, purposely creating a fault condition should not be considered a 'first step' troubleshooting practice.
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
How many devices have you changed, only to find out the problem was with the ground?

IMO, purposely creating a fault condition should not be considered a 'first step' troubleshooting practice.

Well obviously I would rule out the ground issue first, then after the new device is installed i still test the new device.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
How many devices have you changed, only to find out the problem was with the ground?

IMO, purposely creating a fault condition should not be considered a 'first step' troubleshooting practice.

That's exactly what an external push button tester does on a properly grounded 3 prong outlet. Pushing the button creates a path from the hot through a resistor to the grounded terminal.

The point at which such tests are done is moot. As troubleshooters we need to know what the test button does and what it does not do, along with different techniques to solve problems. The test button does nothing to test the electrical components of the GFCI, only a test fault can do that.

To me, pushing the test button and using external testing means are two different tests entirely. Only the first is accepted by the UL. That does not mean that other means are useful to a troubleshooter or not.
 

480sparky

Senior Member
Location
Iowegia
I have to disagree with that. All the test button does is trip the mechanism.

If you shut the power off feeding a GFCI and push the test button it will still trip. I can even be totally not wired and in the box. A properly functioning GFCI will not re-set without power, but will trip with the test button no matter if there is current or not.

Think about this. How can the test button make for an unbalanced current if there is no grounding conductor or other 'third path' back to the source?

The GFCI has access to the neutral BEFORE the sensor. So all it needs is a small resistor placed between that point and the ungrounded conductor after the sensor.

If a GFCI simply tests the mechanics, why does it need power to actually make the 'test' button funtion?
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
The GFCI has access to the neutral BEFORE the sensor. So all it needs is a small resistor placed between that point and the ungrounded conductor after the sensor.

If a GFCI simply tests the mechanics, why does it need power to actually make the 'test' button funtion?

It doesn't. Check one for yourself. Shut off the breaker feeding any GFCI and go push the test button. It will trip.
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
It doesn't. Check one for yourself. Shut off the breaker feeding any GFCI and go push the test button. It will trip.

I don't know all of the nuance of GFCI's but I just couldn't accept what you were saying about the test switch. I quick search of Google turned up this site from Pass and Seymour that disputes your premise. http://tools.passandseymour.com/ProductKnowledge/course.cfm?course_sak=42&cur_page=0&cur_seq=0

Perhaps the older style GFCI's operated the way you describe, but the newer ones automatically open when power is removed. The Fed Govt guidelines for installation tell you to push the button and if the unit doesn't operate it is WIRED wrong. The test button clearly provides an actual fault condition to test the GFCI.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
I tried to no avail to find pics of a GFCI receptacle's innards. Now I want to go tear one apart.

Indeed, it is possible to place a resistor inside and put it into the circuit to create an imbalance. However, real observations do not support the assumption that the test button places a resistor into a circuit.

1) As mentioned, the test button will operate with no power to the receptacle.

2) When pushing the test button, notice how much force you need. You are pushing against a spring that is part of the mechanical system of the GFCI. If all you were doing was operating a small switch, such force would not be needed.

3) I have to test this yet, but if a resistor is used, it should be able to be detected with a meter when the test button is pushed.

4) If a resistor is used, wouldn't it be pretty useless if the test button overrides the electrical side, anyway?
 
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