This is a travesty
- Thread starter peter d
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ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
A hot to an egc will trip a gfci as that is a ground fault- it will detect current taking some other path than thru the noodle.
If you really meant a hot to neutral short circuit, a gfci wont trip b/c it wont sense any imbalance-in this case, the current, while large, will still be taking the intended path thru the neutral- the gfci sees no problem.
ETA- a gfci breaker will trip on a hot to neutral short ckt, (they have the same abilities as standard breakers in addition to their ground fault protection) but a gfci receptacle will not.
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I may have had an odd batch but the last time I took the load side of a GFI Receptacle directly to ground it was enough inrush that it tripped the breaker in the panel as a short circuit without tripping the reset.
Only when I took the load side hot through a load like a soldering gun and then to the EGC did the GFI Trip non violently.
Been a very long time since I tried that so things may be new and improved now.
I'll go and try it again and see what happens.
JAP>
Only when I took the load side hot through a load like a soldering gun and then to the EGC did the GFI Trip non violently.
Been a very long time since I tried that so things may be new and improved now.
I'll go and try it again and see what happens.
JAP>
Well I tried it.
Made a pigtail hot neut and ground to a gfi receptacle I had layin around.
plugged it in and stuck a jumper into the hot side and touched it to the strap.
Tripped the breaker in the panel 4 times in a row.
Tripped the reset once when I very quickly swiped the jumper over the strap but I think that was just a fluke.
I guess things haven't changed at all over the years.
JAP>
Made a pigtail hot neut and ground to a gfi receptacle I had layin around.
plugged it in and stuck a jumper into the hot side and touched it to the strap.
Tripped the breaker in the panel 4 times in a row.
Tripped the reset once when I very quickly swiped the jumper over the strap but I think that was just a fluke.
I guess things haven't changed at all over the years.
JAP>
A gfci will respond to a line to egc fault, its just that the breaker will often beat the gfci and in your experiment the gfci had no chance to see any imbalance between the H&N.
The gfci may have legimately tripped that one time by picking up just enough leakage.
It seems to defy logic- 6ma being a lower threshold than the 100+ amps of fault current you see w/ a standard ocpd, but thats the way it often is- instantaneous trip can be damned fast.:happyyes:
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- Occupation
- Licensed Electrician
It's not about egos, it's about pride of workmanship being thwarted by a device of zero value for its stated purpose, but will trip for no good reason at all.
They are not the same as GFCIs. GFCIs are a safety device that can be tested against a known standard. Everybody knows what 5mA is and you can test with a manufacturer's test button or your own plug tester or a wiggy.
You can't do that with a AFCI. There is nothing that can test them. All we have manufactures' promises that they do work, and we don't know if that is true because they keep coming out with next generation models that have a new wrinkle in the algorithm that won't trip on Panasonic tv power off this time. How do we know they are not writing out arc signatures that are the same as a dangerous arc? WE DON'T.
We do know that AFCIs don't stop a glowing arc, we do know that 120V to ground does not sustain an arc, we do know that the manufactures lied about AFCI capability, and we do know that AFCIs are costing contractors and customers money for no good reason, money that could be better spent on something that will actually save lives.
- Occupation
- Licensed Electrician
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
If they uncover wiring errors, I can live with that, most of those errors a standard GFCi will also uncover. If they won't let you run an appliance that has nothing wrong with it - that is a problem. I have no problem with the intent of reducing the number of electrical fires, lobbying the code making panels to accept them before they are ready was nearly criminal on the manufacturers part, force us to use something that doesn't work as intended, and on top of that what is likely the biggest cause of electrical fires - the "glowing connection" isn't even something they will react to, until it gets to the point that simpler GFCI protection would possibly respond. So far they made a complicated and expensive device that has little benefit for it's cost.
True, they don't prevent fires they respond to a fire.
Current level and time are both factors in when it will trip. Hook your GFCI receptacle to a 100 amp breaker, or maybe a FPE stablock breaker and see if the which trips first.
- Occupation
- Licensed Electrician
No need to do that.
User100 called me out in post #105 saying if you took the hot to the EGC that the GFI would trip because it's a ground fault not a short circuit and I was probably meaning to say hot to "noodle" as he referred to it and not EGC.
I meant what I said to begin with.
Most times a direct short from the load side hot of a GFI Receptacle's EGC will bypass the GFI mechanism in the receptacle itself and trip the breaker feeding it.
With an arc much more violent than what you would witness on a simple GFI mechanism trip.
JAP>
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
And it is just a matter of whether the GFCI receptacle or the circuit breaker would have a faster response time to the conditions, some cases they both may trip, but a breaker with low instantaneous trip setting, like standard 15/20 amp single pole QO series, may respond first in most cases.
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