GFCI Receptacle For Appliance With 3 - Prong Cord.

Status
Not open for further replies.
Ravenvalor

Ravenvalor

Senior Member
Location
Triad region of NC
Occupation
Electrician
Good Afternoon,

A Belated happy 4th to all ! ! !

Does one know whether or not a person can use a GFCI receptacle without an equipment grounding conductor connected to it if the GFCI is used to supply power to an appliance that has a 3 - prong cord?

Thank you,
 
Ravenvalor said:
Good Afternoon,

A Belated happy 4th to all ! ! !

Does one know whether or not a person can use a GFCI receptacle without an equipment grounding conductor connected to it if the GFCI is used to supply power to an appliance that has a 3 - prong cord?

Thank you,
Click to expand...
You can do this, but you do not get any benefit from the third wire in the cord. It will be safer to use than the same appliance a two wire connection but no GFCI.
If the manufacturer's instructions actually call for a grounded connection, then this will not be legal. But the GFCI will work and do its intended protective function.
It may not trip after a fault until you supply the missing fault current path back to the neutral though. :)
 
Your point about the fault not clearing until it reaches the neutral is well taken GoldDigger.

I had a home inspector write up some GFCIs because 3 - prong cord appliances were plugged into them. The inspector said this was a code violation but I had never run across this code.

Thank you for the advice.
 
Take a look at 250.114. Generally if an appliance or piece of equipment has a "3-prong plug" it is required to be connected to an equipment grounding conductor.
 
GoldDigger said:
It may not trip after a fault until you supply the missing fault current path back to the neutral though. :)
Click to expand...

I'm struggling with the wording used here.

If the fault current returns through the neutral, presumably after the GFCI, wouldn't that result in a balance between hot and neutral and not trip the GFCI? If it faulted to earth the fault current wouldn't return via the neutral, would result in imbalance and would trip the GFCI.

Right?
 
I was just referring to the fact that the current which is flowing to "ground" is actually flowing back to the utility neutral, just not through the normal neutral path that goes through the GFCI. :)
 
Somehow I have not previously been aware of 250.114 (3).

I often work on houses wired with 12/ and 14/2 romex, no ground (what we used to call "plain"). Obviously these are older houses usually containing some handyman or DIY mistakes, I find many 3/prong recptacles that have nothing connected to ground screw.

One of my solutions is to change out to GFCI receptacles. Is this legal only until something is plugged in that is on the list? Is the receptacle in the refrigerator space in cabinets legal only until the refrigerator is plugged in?
 
don_resqcapt19 said:
Take a look at 250.114. These items are required to be connected to a circuit that has an EGC.
Click to expand...

This is a broad reaching code. I wonder why I have never been turned down by any of the local electrical inspectors. Is it possible that they consider an existing receptacle as being grandfathered in?
 
Ravenvalor said:
This is a broad reaching code. I wonder why I have never been turned down by any of the local electrical inspectors. Is it possible that they consider an existing receptacle as being grandfathered in?
Click to expand...
Well, the use if a GFCI 3- wire receptacle for replacing a two wire receptacle is clearly spelled out in the code.
But one of the requirements is to place the "no equipment ground" label on the receptacle.
That makes it OK by the inspector.
The next step, unfortunately, is that the homeowner has the responsibility not to plug a 3-wire appliance into that outlet.
To help with this the homeowner should either only use 2-wire cords or put his own " no ground" label in the end of a 3-wire cord. But the NEC (or at least the inspector) does not see any of this.
 
curt swartz said:
Take a look at 250.114. Generally if an appliance or piece of equipment has a "3-prong plug" it is required to be connected to an equipment grounding conductor.
Click to expand...

don_resqcapt19 said:
Take a look at 250.114. These items are required to be connected to a circuit that has an EGC.
Click to expand...

GoldDigger said:
Well, the use if a GFCI 3- wire receptacle for replacing a two wire receptacle is clearly spelled out in the code.
But one of the requirements is to place the "no equipment ground" label on the receptacle.
That makes it OK by the inspector.
The next step, unfortunately, is that the homeowner has the responsibility not to plug a 3-wire appliance into that outlet.
To help with this the homeowner should either only use 2-wire cords or put his own " no ground" label in the end of a 3-wire cord. But the NEC (or at least the inspector) does not see any of this.
Click to expand...


I think the key to this would be the wording "likely to become energized". How do you define "likely to become energized"? Everything metal isn't necessarily "likely" to become energized. Seems like "capable of being energized" would be a better choice of words.

Just what purpose would replacing a non-grounded, 2-wire receptacle with a GFCI serve if you can't plug in any 3-wire cord? Safety isn't always what a customer is looking for when they want either a 3-wire receptacle or GFCI to replace a 2-wire recep. They are just wanting to be able to plug in their 3-wire equipment.

Seems the code is contradicting itself by allowing a GFCI to replace a non-grounded receptacle and also saying elsewhere that, basically, an EGC must be run to plug in anything with a ground pin on it. Also, the code can't police what a customer plugs in to any receptacle, and shouldn't even write a code to try.
 
IMHO the CMP recognized that a two wire cord with GFCI is safer than the same cord and appliance without GFCI and that it was not practical to expect anyone to make and sell a two wire GFCI receptacle.
I do not think that they intended the ungrounded receptacle to be used for equipment that requires a ground for safety. But, then again two to three wire adapters are sold that are often used without the ground tab connected to anything. :)
 
Does anyone seriously believe that the Code allows the installation of three prong grounding-type receptacles without a connection to the grounding connection and not expect three pronged plugs to be plugged in?

Does anyone seriously believe that appliances, luminaires, and such that have three pronged plugs exist that do not "require grounding"? If so describe one to me.

It is clear to me that the requirement for GFCI protection of such ungrounded "grounding" receptacles has the intent of having the GFCI protection substitute for grounding. Otherwise the only reason for this scheme is to allow you to plug in a three wire extension cord or plug strip which would then be allowed to only be used by 2 prong plugs. Sounds BOGUS to me.

I believe the "No Equipment Ground" label is for those rare instances when an equipment ground is required for proper functioning of a device or interconnected devices. The only device that comes to mind is the plugin GFCI tester that needs a grounding conductor to trip the testee.

250.114 Equipment Connected by Cord and Plug.
Under any of the conditions described in 250.114(1) through (4), exposed, normally non?current-carrying metal parts of cord-and-plug-connected equipment shall be connected to the equipment grounding conductor.
-- General Rule --

406.4 General Installation Requirements.
Receptacle outlets shall be located in branch circuits in accordance with Part III of Article 210. General installation requirements shall be in accordance with 406.4(A) through (F).

(A) Grounding Type.
Except as provided in 406.4(D), receptacles installed on 15- and 20-ampere branch circuits shall be of the grounding type. Grounding-type receptacles shall be installed only on circuits of the voltage class and current for which they are rated, except as provided in Table 210.21(B)(2) and Table 210.21(B)(3).
-- Receptacles shall be grounding --
....
(D) Replacements.
Replacement of receptacles shall comply with 406.4(D)(1) through (D)(6), as applicable. Arc-fault circuit-interrupter type and ground-fault circuit-interrupter type receptacles shall be installed in a readily accessible location.
....
(2) Non?Grounding-Type Receptacles.
Where attachment to an equipment grounding conductor does not exist in the receptacle enclosure, the installation shall comply with (D)(2)(a), (D)(2)(b), or (D)(2)(c).
-- if no grounding available --

(a) A non?grounding-type receptacle(s) shall be permitted to be replaced with another non?grounding-type receptacle(s).
-- you can use a two prong receptacle --

(b) A non?grounding-type receptacle(s) shall be permitted to be replaced with a ground-fault circuit interrupter-type of receptacle(s). These receptacles shall be marked ?No Equipment Ground.? An equipment grounding conductor shall not be connected from the ground-fault circuit interrupter-type receptacle to any outlet supplied from the ground-fault circuit-interrupter receptacle.
-- or a three prong GFCI --

(c) A non?grounding-type receptacle(s) shall be permitted to be replaced with a grounding-type receptacle(s) where supplied through a ground-fault circuit interrupter. Grounding-type receptacles supplied through the ground-fault circuit interrupter shall be marked ?GFCI Protected? and ?No Equipment Ground.? An equipment grounding conductor shall not be connected between the grounding-type receptacles.
-- or a 3 prong receptacle protected by a GFCI --
 
GoldDigger said:
IMHO the CMP recognized that a two wire cord with GFCI is safer than the same cord and appliance without GFCI and that it was not practical to expect anyone to make and sell a two wire GFCI receptacle.
I do not think that they intended the ungrounded receptacle to be used for equipment that requires a ground for safety. But, then again two to three wire adapters are sold that are often used without the ground tab connected to anything. :)
Click to expand...
Since option of GFCI breaker was already available to protect 2/prong receptacle, and for other reasons, I doubt that this was the motivation of CMP.
 
fmtjfw said:
Does anyone seriously believe that the Code allows the installation of three prong grounding-type receptacles without a connection to the grounding connection and not expect three pronged plugs to be plugged in?
Click to expand...

Absolutely what the words say.


Does anyone seriously believe that appliances, luminaires, and such that have three pronged plugs exist that do not "require grounding"? If so describe one to me.
Click to expand...

Not I.

It is clear to me that the requirement for GFCI protection of such ungrounded "grounding" receptacles has the intent of having the GFCI protection substitute for grounding.
Click to expand...

Then you had best out in a proposal for an exception to 250.114.
 
The only reason the code allows GFCI and three wire plugs on two wire circuits is to allow a three wire cord to be plugged in. It's the only thing that makes sense.

As far as "likely to become energized" EGC are the least likely to become energized. Most of them sit around just hoping for the chance and it never happens. They get ripped out and replaced before they ever feel the thrill of conducting current.
 
ActionDave said:
The only reason the code allows GFCI and three wire plugs on two wire circuits is to allow a three wire cord to be plugged in. It's the only thing that makes sense.
Click to expand...

I won't argue with that, but it still does not change the requirements of 250.114.

Keep in mind 250.114 is controlled by CMP 5 and 406.4 is controlled by CMP 18.

I do not think it is any kind of stretch to think one CMP may not be on the same page as another CMP.




As far as "likely to become energized" EGC are the least likely to become energized. Most of them sit around just hoping for the chance and it never happens. They get ripped out and replaced before they ever feel the thrill of conducting current.
Click to expand...

:huh:

:?

:D
 
I had a whole lot racier description of the life of a EGC but re-typed it out of respect for the owner of this forum, but really, how often do ground faults occur in a house...anywhere for that matter?

I don't have any numbers, but out of all places likely to become energized EGCs and any possible related paths have to be on the bottom of the list. When they do get in the flow a GFCI is as good as, or even better to have, in the circuit.
 
Status
Not open for further replies.
Top