What would cause a GFCI to show no ground with a receptacle tester, the test reset works but an outside source that tests GFCIs does not trip it? I would think that the self TEST/RESET is not a true test of the system. It seems as though the test may work but in reality the GFCI would fail during an actual hazard. The tester works just fine and continues to work so let's not blame the tester.
GFCI trip/no trip
- Thread starter jar546
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- Illinois
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- retired electrician
Re: GFCI trip/no trip
Bennie is correct. Your plug-in GFCI tester requires an equipment grounding conductor to function and without one, it will not trip the beaker. The interal test puts a load from the hot on load side of the current sensor to the neutral on the line side of the sensor creating an imbalance of current through the sensor. This is a true test. The GFCI does not require the EGC to function. If there is any leakage above the 4 to 6 mA trip point the GFCI will open the circuit.
Don
Bennie is correct. Your plug-in GFCI tester requires an equipment grounding conductor to function and without one, it will not trip the beaker. The interal test puts a load from the hot on load side of the current sensor to the neutral on the line side of the sensor creating an imbalance of current through the sensor. This is a true test. The GFCI does not require the EGC to function. If there is any leakage above the 4 to 6 mA trip point the GFCI will open the circuit.
Don
Re: GFCI trip/no trip
Thanks for the info.. So basically unless a person who is "grounded" comes in contact with a live circuit, it will not trip. If a person held the hot and neutral wire at the same time without being grounded, current would flow and without the grounding they would become part of the live circuit, therefore no GFCI trip because there was no leak of current to ground. Unless you are grounded, the GFCI will not work.
So, there is a minimal gain in replacing an older ungrounded receptacle with a GFCI. But then again a person can pick up a ground somewhere in the house. I was hoping that there would be a separate tester that would trip a GFI without a ground.
Thanks for the info.. So basically unless a person who is "grounded" comes in contact with a live circuit, it will not trip. If a person held the hot and neutral wire at the same time without being grounded, current would flow and without the grounding they would become part of the live circuit, therefore no GFCI trip because there was no leak of current to ground. Unless you are grounded, the GFCI will not work.
So, there is a minimal gain in replacing an older ungrounded receptacle with a GFCI. But then again a person can pick up a ground somewhere in the house. I was hoping that there would be a separate tester that would trip a GFI without a ground.
- Location
- Illinois
- Occupation
- retired electrician
Re: GFCI trip/no trip
jar,
A GFCI is not intented and will not provide protection from line to neutral shocks. If a line to neutral shock is associated with a ~5mA ground fault the GFCI will open the circuit. As far as increased safety, if there are no grounds of any type, there is no hazard in touching the circuit conductors one at a time.
Why do you think that you need a tester other than the one built into the device?
Don
jar,
A GFCI is not intented and will not provide protection from line to neutral shocks. If a line to neutral shock is associated with a ~5mA ground fault the GFCI will open the circuit. As far as increased safety, if there are no grounds of any type, there is no hazard in touching the circuit conductors one at a time.
Why do you think that you need a tester other than the one built into the device?
Don
hurk27
Senior Member
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- Portage, Indiana NEC: 2008
Re: GFCI trip/no trip
and yes if a person were to get in-between the hot and neutral they would get shocked as a GFCI can not protect against this type of contact as it would also make this circuit un-usable because if the GFCI protected the hot to neutral connection then any thing that was pluged in that drawed a load higher than the 5ma trip level would trip the GFCI.
But to replace two-wire receptacles with gfci's would be better as it would still trip if someone were useing an appliance that had a ground fault and came into contact with somthing that is grounded, then the gfci would protect them.
Jar it will trip if a person touches a hot conductor and somthing grounded even if there is no ground wire to the GFCI. the GFCI does not need a ground wire to know that there is current being pulled from anothe source I.E. (ground) This is what Don has said.
and yes if a person were to get in-between the hot and neutral they would get shocked as a GFCI can not protect against this type of contact as it would also make this circuit un-usable because if the GFCI protected the hot to neutral connection then any thing that was pluged in that drawed a load higher than the 5ma trip level would trip the GFCI.
But to replace two-wire receptacles with gfci's would be better as it would still trip if someone were useing an appliance that had a ground fault and came into contact with somthing that is grounded, then the gfci would protect them.
Re: GFCI trip/no trip
Thanks for all the replies and what I learned so far was that the GFCI self tester does not require the ground to be hooked up AND an outside tester will not trip the GFCI if it has no ground. When I test receptacles that are downstream from a GFCI, it is easier to use a 3 prong receptacle tester with a "trip" function on it than to keep walking back to make sure that it is actually hooked up. I have been using a Fluke DMM since 1983 and absolutely love it. Since I started doing home inspections I find it easier to use an outlet tester. Thanks to everyone for their input and assistance.
Thanks for all the replies and what I learned so far was that the GFCI self tester does not require the ground to be hooked up AND an outside tester will not trip the GFCI if it has no ground. When I test receptacles that are downstream from a GFCI, it is easier to use a 3 prong receptacle tester with a "trip" function on it than to keep walking back to make sure that it is actually hooked up. I have been using a Fluke DMM since 1983 and absolutely love it. Since I started doing home inspections I find it easier to use an outlet tester. Thanks to everyone for their input and assistance.
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