Non Grounded duplex poll. Which is safer?

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Non Grounded duplex poll. Which is safer?

  • A 3 wire circuit with equipment ground

    Votes: 36 55.4%

  • A 2 wire circuit with GFCI protection

    Votes: 29 44.6%
  • Total voters
    65
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M4gery

M4gery

Senior Member
Is that failure in their ability to react to a ground fault? Or do they simply not work at all? That would be a huge difference as far as safety.
 
jumper

jumper

Senior Member
Location
3 Hr 2 Min from Winged Horses
jxofaltrds said:
Thank you.

"A grounding-type receptacle that is GFCI protected without an equipment grounding conductor is a safer installation than a grounding-type receptacle with an equipment grounding conductor (if GFCI protection is not provided). ".
Click to expand...

You are welcome, but MH also states:

WARNING: According to a study (based on data accumulated by the American Society of Home Inspectors) published in the November/December, 1999 issue of the IAEI News, out of 1,583 GFCI circuit breakers tested, 21% had failed. Out of 4,585 GFCI receptacles tested, 19% had failed. The failures were primarily attributed to damage from short circuits and voltage surges (lightning and other transients) to the metal oxide varistors (MOV) that are used for built-in surge suppression. In areas of high lighting activity such as Southwest Florida, the failure rate for GFCI circuit breakers was over 57%!
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and:

A grounding-type receptacle without a ground is a safe installation as long as the GFCI protection circuitry within the device has not failed from shorts and voltage transients. To insure proper GFCI protection, test the GFCI monthly in accordance with the manufactures instructions and if the GFCI test does not operate properly, replace the GFCI protection device.
Click to expand...
 
kwired

kwired

Electron manager
Location
NE Nebraska
M4gery said:
Is that failure in their ability to react to a ground fault? Or do they simply not work at all? That would be a huge difference as far as safety.
Click to expand...

Back at that time I'm pretty certain that it meant there was no reliable GFCI protection but the receptacle would still pass power to anything plugged into it. That is likely part of the reason their instructions said to test monthly.

I have seen many older GFCI's that will not trip when you apply unbalanced current well above where they are supposed to trip.

I think today many (maybe all if properly listed) have circuitry that does not allow operation of the receptacle if the GFCI protection is compromised.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
kwired said:
...
I think today many (maybe all if properly listed) have circuitry that does not allow operation of the receptacle if the GFCI protection is compromised.
Click to expand...
While they will not permit a reset after a test if they are damaged, most do not kill the output when the electronics fail. Some have an indication of failure, but they still don't kill the output.
 
renosteinke

renosteinke

Senior Member
Location
NE Arkansas
The two are as different as cheese and chalk- and life is about compromises.

A GFCI won't help a fault clear any faster ... and a breaker will shock the life out of you long before it ever trips. Different technology to address different problems.

Yet, the NEC panel recognized that it's not always practical to re-wire a house- so they allowed a compromise with the intent of saving lives. Half a loaf being better than none. No one ever claimed that one was a substitute for the other.

Article 90 .... it's worth remind ourselves how the 'forest' looks from time to time.
 
2

220/221

Senior Member
Location
AZ
frankft2000 said:
A local city informed me that they do not recognize replacing a non grounded receptacle with GFCI protection. That got me thinking about safety.
Click to expand...

Your poll options seem wrong. To reflect the options given by the city they should be:

Which is more safe?

A) Two wire, ungrounded receptacles.

B) Three wire receps on a two wire system with GFCI protection.
 
kwired

kwired

Electron manager
Location
NE Nebraska
don_resqcapt19 said:
While they will not permit a reset after a test if they are damaged, most do not kill the output when the electronics fail. Some have an indication of failure, but they still don't kill the output.
Click to expand...

I question how one would sucessfully make it trip during testing if that is the case. My understanding is all the test button does is apply a 5-7ma load from hot to neutral with only one side of the test circuit passing through the monitoring CT to cause an unbalance and cause the device to trip.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
kwired said:
I question how one would sucessfully make it trip during testing if that is the case. My understanding is all the test button does is apply a 5-7ma load from hot to neutral with only one side of the test circuit passing through the monitoring CT to cause an unbalance and cause the device to trip.
Click to expand...
My understanding is with the newer GFCIs, the test button itself is a only a mechanical trip. The simulated ground fault and circuit testing takes place on reset. If those tests are successful the device resets and if not it doesn't.
 
kwired

kwired

Electron manager
Location
NE Nebraska
don_resqcapt19 said:
My understanding is with the newer GFCIs, the test button itself is a only a mechanical trip. The simulated ground fault and circuit testing takes place on reset. If those tests are successful the device resets and if not it doesn't.
Click to expand...

That makes sense. You still need to follow directions and test monthly to be truly protected. Out of the millions of devices out there how many do you suppose get tested on any regular basis, or even just whenever someone thinks about it? (Electrcians testing them don't count)

I can think of a few places with written policies or extensive safety inspection programs that probably do test them, although probably not every month.
 
A

arnettda

Senior Member
For those that think a three wire system is safer, does this mean you will not replace a two wire recep with a GFCI?
 
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