Hey, I'm new here.......got a question on ground fault outlets. If you plug in a piece of equipment to a ground fault outlet and it keeps popping the outlet, but if you plug the equipment into a standard outlet it will work. Why is that. I was told at first it had to do with the neutral and ground on the piece of equipment being tied together somehow. Is that true?
Ground faults circiuts
- Thread starter dinky
- Start date
- Status
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Ground faults circiuts
It also means that you have to repair the equipment (or at least investigate further, to see if this really was the cause), before someone gets hurt.
It also means that you have to repair the equipment (or at least investigate further, to see if this really was the cause), before someone gets hurt.
- Location
- Bremerton, Washington
Re: Ground faults circiuts
The piece of equipment that is tripping the GCI has a "ground fault". There is more than 4-6 mA leaking to ground, it could be much higher, and keep in mind at 30 mA it could easily cause a fatal shock if plugged into a standard receptacle.
The piece of equipment that is tripping the GCI has a "ground fault". There is more than 4-6 mA leaking to ground, it could be much higher, and keep in mind at 30 mA it could easily cause a fatal shock if plugged into a standard receptacle.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Ground faults circiuts
In both cases, it only LOOKS LIKE the equipment works. It is not working, and it may even be dangerous. A fridge may appear to be working, because it keeps stuff cold and it doesn?t trip its breaker. But it can still have a leakage current that might even be high enough to hurt someone.
Remember: If a standard breaker could have kept everything safe, there would not have been a need to invent the GFCI, and there would be no code requirement for using a GFCI. In reality, the GFCI can detect a problem that a standard breaker cannot detect, and will therefore give us greater protection. If a GFCI is tripping, then something is wrong.
I hope this does not sound too harsh, but both of these statements are untrue!
In both cases, it only LOOKS LIKE the equipment works. It is not working, and it may even be dangerous. A fridge may appear to be working, because it keeps stuff cold and it doesn?t trip its breaker. But it can still have a leakage current that might even be high enough to hurt someone.
Remember: If a standard breaker could have kept everything safe, there would not have been a need to invent the GFCI, and there would be no code requirement for using a GFCI. In reality, the GFCI can detect a problem that a standard breaker cannot detect, and will therefore give us greater protection. If a GFCI is tripping, then something is wrong.
- Location
- Massachusetts
Re: Ground faults circiuts
I can not remember a time when a GFCI was tripping because of a problem internal to the GFCI.
That has always been what I have found when sent to service tripping GFCIs.
I can not remember a time when a GFCI was tripping because of a problem internal to the GFCI.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Ground faults circiuts
It?s not impossible that the code could evolve in that direction, but not soon and not quickly. If current leaves the source via the hot leg, and does not return via the cold leg, then something is wrong. A GFCI can detect that problem, and will terminate the event by tripping the breaker (or the receptacle).
It?s not impossible that the code could evolve in that direction, but not soon and not quickly. If current leaves the source via the hot leg, and does not return via the cold leg, then something is wrong. A GFCI can detect that problem, and will terminate the event by tripping the breaker (or the receptacle).
Re: Ground faults circiuts
GFCI is not the ultimate in electrical safety and is no substitute for proper grounding! A GFCI device will protect the user against electrocution, but not against electrical shock. There are dangers from shock other than electrocution. The "jerk" reaction from a shock can cause an injury or a fall, for example. Proper grounding protects against both electrocution and shock. Many refrigerators leak sufficient voltage to trip a GFCI device. That is the reason that refrigerators are allowed to be installed on a seperate non GFCI protected circuit in a dwelling kitchen. If they are properly grounded, they will not pose a hazard.
GFCI is not the ultimate in electrical safety and is no substitute for proper grounding! A GFCI device will protect the user against electrocution, but not against electrical shock. There are dangers from shock other than electrocution. The "jerk" reaction from a shock can cause an injury or a fall, for example. Proper grounding protects against both electrocution and shock. Many refrigerators leak sufficient voltage to trip a GFCI device. That is the reason that refrigerators are allowed to be installed on a seperate non GFCI protected circuit in a dwelling kitchen. If they are properly grounded, they will not pose a hazard.
- Location
- Illinois
- Occupation
- retired electrician
Re: Ground faults circiuts
haskindm,
Don
haskindm,
Not completely true. Under fault conditions, there will be a voltage drop on the equipment grounding conductor. This voltage will be there until the overcurrent protective device operates and will create a shock hazard between the conductive parts of the faulted equipment and any other grounded objects within reach. Based on the code sizing of the EGC, the voltage drop can be 40 to 50 volts is enough to be dangerous to some people.
Don
B
bthielen
Guest
Re: Ground faults circiuts
Thought I'd pass along a little experience I had once. I used a GFCI receptacle to protect a branch circuit. When I powered the circuit, the GFCI tripped. After troubleshooting for quite some time, I finally found out that it was not a ground fault at all. What it turned out to be was a poor connection inside a wirenut of grounded (neutral) conductors inside a light fixture receptacle. All I did was tighten the wirenut a little better and the problem went away.
I like to twist my wires before applying a wirenut. What is the possibility that this contributed to the problem or is not twisting more likely to produce poor connections?
Bob
Thought I'd pass along a little experience I had once. I used a GFCI receptacle to protect a branch circuit. When I powered the circuit, the GFCI tripped. After troubleshooting for quite some time, I finally found out that it was not a ground fault at all. What it turned out to be was a poor connection inside a wirenut of grounded (neutral) conductors inside a light fixture receptacle. All I did was tighten the wirenut a little better and the problem went away.
I like to twist my wires before applying a wirenut. What is the possibility that this contributed to the problem or is not twisting more likely to produce poor connections?
Bob
Re: Ground faults circiuts
I have to back Don up on this one. IMO the voltage drop on the EGC can be as high as 60 volts or more. I base this opinion on results of acceptance/commissioning testing. It just a simple voltage divider circuit, assuming the EGC and ungrounded conductor are the same size, then the voltage can be 60 volts on a single phase 120 volt circuit. However, if the ungrounded conductor is larger than the EGC, the voltage will be higher than 60 volts, or greater than half the supply voltage.
james wuebker
Senior Member
- Location
- Iowa
Re: Ground faults circiuts
I've seen this problem before. Found that the panel where the power was coming from (sub panel most of the time) wasn't proboaly grounded correctly. The N & the grounding wires weren't seperated causing the neutral and grounding wire to be in a parallel back to the main service which would cause return amps on this circuit to be diffent.
Jim
I've seen this problem before. Found that the panel where the power was coming from (sub panel most of the time) wasn't proboaly grounded correctly. The N & the grounding wires weren't seperated causing the neutral and grounding wire to be in a parallel back to the main service which would cause return amps on this circuit to be diffent.
Jim
- Status