Two-wire system

[Jaykline]

I thought I'd read somewhere that three-prong receptacles used on a two wire circuit should be labeled somehow ("No ground"?). Is that correct or am I imagining things?

[hausdok]

Hi,

I think you've gotten the GFCI labeling requirement confused with regular wiring.

Here's what Douglas Hansen says about the issue in his book Electrical Inspection of Existing Dwellings 2001 Edition:

Page 6.24 - Replacements

Whenever a receptacle is replaced in an area presently requiring GFCI protection, it must be provided with GFCI protection, either by using a GFCI or by installing a GFCI breaker on the circuit. The requirement for the GFCI does not depend on whether an equipment grounding conductor is present, though if one is there is should be used. What this means is that if you replace a bathroom receptacle, or a kitchen counter receptacle, the requirement for a GFCI becomes retroactive[210-7d2].

If no equipment ground is present, labels are supposed to be attached to the faceplate of the receptacle indicating the lack of an equipment ground. If other receptacles are protected downstream from the GFCI with no ground, then those receptacls are supposed to have two stickers. One states "GFCI Protected" and the other says "No equipment Ground" as in figure 6.47.(illustration omitted)

There are often misconceptions about when the labels are required. If grounding is present, the labels are never needed. In earlier code editions, not all garage and basement receptacles were required to be GFCI's, and the ones that were GFCI protected required labeling. Perhaps the overuse of these labels is a result of these outdated practices.

ONE TEAM - ONE FIGHT!!!

Mike

[crusty]

I do not recommend the practice. They are unsafe and not allowable. I always recommend that they be rewired with an approved equipment grounding conection or properly replaced with 2 prong devices or GFCI protected.

[Jim Katen]

Originally posted by crusty

I do not recommend the practice. They are unsafe and not allowable. I always recommend that they be rewired with an approved equipment grounding conection or properly replaced with 2 prong devices or GFCI protected.

I wouldn't include the choice about reverting to 2-slot outlets. Seems like a step backwards.

After explaining the problem, my reports say, "Ensure that all three-slot receptacles are either properly grounded or gfci-protected for safety."

- Jim Katen, Oregon

[crusty]

Good point Jim, but I also generally point out to people that the need for grounding outlets has diminished considerably since our colleges started cranking lawyers out like popcorn from a kettle. If the appliance in use is manufactured with a 2 prong plug, there is no need for a grounded receptacle to serve it.

IMO 2 prong outlets are still a viable alternative in most rooms in a house where few appliances are ever used with 3 prong plugs. The point I like to stress to my clients is that if the appliance has 3 prongs it needs to be grounded and my personal opinion is that ungrounded GFCI's do not provide the same protection. I know it is NEC approved but I personally don't like it. I like to see 3 wires.

The latest estimate from Dan Friedman is that there may be as many as 56 million miswired GFCI outlet in use right now that do not shut down the power when tripped, giving consumers a false sense of security. I would prefer to take my chances with restoration to 2 prong devices where there is no ground wire. I prefer to recommended adding one or two properly grounded outlets in each bedroom dining room or living room since houses of that vintage are usually pretty short on available outlets. Of course I also recommend abandoning antique services and the K&T wiring but I would hate to place my money on that happening. San Mateo County CA was still using K&T into the sixties I believe.

IMO the real issue is a false sense of security caused by thinking the outlets are grounded when indeed they are not and Friedman believes there is a 19 in 100 chance that the same problem exists with the old style GFCI's. Of course as I think about it the supply of old style GFCI's should now be depleted and the new improved models should make GFCI installations by the agents' handymen foolproof I should most likely and very gladly change my tune.

Thanks,

st

[Jim Katen]

Originally posted by crusty

Good point Jim, but I also generally point out to people that the need for grounding outlets has diminished considerably since our colleges started cranking lawyers out like popcorn from a kettle. If the appliance in use is manufactured with a 2 prong plug, there is no need for a grounded receptacle to serve it.

Of course that's true. However, those appliances can still cause ground faults. A two-slot outlet or a castrated three-slot outlet won't provide any protection against them. A gfci will (properly installed, working right, etc, etc.)

IMO 2 prong outlets are still a viable alternative in most rooms in a house where few appliances are ever used with 3 prong plugs.

I'm not so sure that the NEC agrees with that position. As I interpret it, once someone's installed a 3-slotter, they aren't supposed to go back to a two-slotter. Though I'll admit it's an argueable point.

The point I like to stress to my clients is that if the appliance has 3 prongs it needs to be grounded and my personal opinion is that ungrounded GFCI's do not provide the same protection. I know it is NEC approved but I personally don't like it. I like to see 3 wires.

GFCIs don't provide the *same* protection. They provide *better* protection, at least for people. You can still be fried by a properly grounded outlet. It's much harder to do that when a gfci's installed.

The latest estimate from Dan Friedman is that there may be as many as 56 million miswired GFCI outlet in use right now that do not shut down the power when tripped, giving consumers a false sense of security. I would prefer to take my chances with restoration to 2 prong devices where there is no ground wire. I prefer to recommended adding one or two properly grounded outlets in each bedroom dining room or living room since houses of that vintage are usually pretty short on available outlets. Of course I also recommend abandoning antique services and the K&T wiring but I would hate to place my money on that happening. San Mateo County CA was still using K&T into the sixties I believe.

IMO the real issue is a false sense of security caused by thinking the outlets are grounded when indeed they are not and Friedman believes there is a 19 in 100 chance that the same problem exists with the old style GFCI's. Of course as I think about it the supply of old style GFCI's should now be depleted and the new improved models should make GFCI installations by the agents' handymen foolproof I should most likely and very gladly change my tune.

Thanks,

st

The hazard of mis-wired gfcis is real. Though, in my experience, much less than 20%. In the homes I've inspected, I'd put it closer to 5%. In any case, around here, you haven't been able to buy the old-style gfci's for over a year now. Nothing but the new ones on the shelves. They do what they should. If they're mis-wired, they won't provide power.

- Jim Katen, Oregon

[crusty]

I'm obviously running a few months behind and totally agree with you Jim. An article Douglas just provided for our CREIA Inspector magazine noted old style on the shelves as late as April in our area. Like I said I am obviously slow in changing my ways. For years I've been running into houses placed on the market where the standard is to have the listing agent's handyman install shiny new 3 prong devices and cover plates to match the new white carpet and newly painted walls, obviously without pulling an equipment grounding conductor. IMO this was a huge hazard and I was a total wiring Nazi a$$h0le in making the calls. Regardless of NEC I always recommend(ed) that at a minimum they put 2 prong outlest back in. Now I think I'll go edit my comment library.

thanks

st