4 wire dryer outlet or 3 wire?

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Jim W in Tampa

Senior Member
Location
Tampa Florida
I believe it was in mike holts tapes on master that i heard it,could be wrong.Idea was to save copper and since it seemed to cause no problem was permitted to continue.Please dont ask me to view all 20 = hours to find it.
 

mario

Senior Member
Location
Alaska
I thought that the 4 prong plug was made mandatory because of the fact that, as previously stated, the neutral and ground were being put together in the dryer, which in essence is bonding them together a second time ... not good ...
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Jim W in Tampa said:
What you did was a violation in my opinion. You now have a piece of equipment that requires equipment ground. While she wont get killed what you did wasn't good fix
I don't agree. If an existing home does not have a conductor available to serve as an EGC, then we are permitted to install a 3-prong receptacle, and label it with "no equipment ground." I don't recall the NEC article off the top of my head, but I am confident it exists.

Adding the GFCI provided an extra level of protection against shock. Even without an EGC, a GFCI will trip if a short circuit causes current to flow through a person's body.
 

mario

Senior Member
Location
Alaska
mario said:
I thought that the 4 prong plug was made mandatory because of the fact that, as previously stated, the neutral and ground were being put together in the dryer, which in essence is bonding them together a second time ... not good ...

:?: ... I was really hoping to get some comments on this ... anybody ?? ...
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
charlie b said:
Jim W in Tampa said:
What you did was a violation in my opinion. You now have a piece of equipment that requires equipment ground. While she wont get killed what you did wasn't good fix
I don't agree. If an existing home does not have a conductor available to serve as an EGC, then we are permitted to install a 3-prong receptacle, and label it with "no equipment ground." I don't recall the NEC article off the top of my head, but I am confident it exists.

Adding the GFCI provided an extra level of protection against shock. Even without an EGC, a GFCI will trip if a short circuit causes current to flow through a person's body.
Thats all true but your missing my point.If that micro was to have equipment grounding then you took it away.Thats violating its instructions.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Jim W in Tampa said:
If that micro was to have equipment grounding then you took it away. That's violating its instructions.
That would have been true, if the microwave did have an equipment ground. But it did not. It had something that (illegally) resembled an equipment ground; it had a neutral to ground connection at the receptacle. Removing that jumper did not create a violation; it resolved a violation.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
charlie b said:
Jim W in Tampa said:
If that micro was to have equipment grounding then you took it away. That's violating its instructions.
That would have been true, if the microwave did have an equipment ground. But it did not. It had something that (illegally) resembled an equipment ground; it had a neutral to ground connection at the receptacle. Removing that jumper did not create a violation; it resolved a violation.
Yes his removing it did remove the first violation but his using a gfci did not make using this micro legal either.What he managed to do was give her a 3 prong outlet that in itself is permitted.But it requires you place a sticker saying NO EQUIPMENT GROUND.Now the violation begins when he plugs a micro into it that REQUIRES an equipment ground.Just what do you think that sticker means ? I really think the code needs to change on this in a way to purhaps plug up that ground hole.We all know few will understand it and the sticker comes off easy leaving no warning for others.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
charlie b said:
Even without an EGC, a GFCI will trip if a short circuit causes current to flow through a person's body.
That's true if the source of the fault is the equipment supplied by the GFCI.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
I will agree that it is safer now.But where in nec does it say i can supstiute a needed equipment ground if i use a gfci ? If there is no need then why put the label on it.My understanding is if we wanted gfci protection at lets say a kitchen counter but have no ground wire we can install this outlet.And that works great for everything that never had the 3rd prong to start with,such as toaster,mr coffee,electric skillet,blender,etc.Very few items even use a ground anymore but the ones that do still need it.
 
What he managed to do was give her a 3 prong outlet that in itself is permitted.But it requires you place a sticker saying NO EQUIPMENT GROUND.Now the violation begins when he plugs a micro into it that REQUIRES an equipment ground

I do not agree. My thought process goes like this: We all know the purpose of equipment grounding - to deactivate the circuit if metal parts become energized, thus alerting us that there is a problem. A 2-wire GFI protected receptacle does the same thing, protects us from shocks, just in a slightly different way. The GFI wont deactivate the circuit when a frayed hot wire come in contact with a metal frame, but it will when you are grounded and touch the energized metal frame.

I don't agree that it is against code to plug a three prong plug into a three prong GFI protected ungrounded receptacle. If it was, why did they put the exception in the NEC that allows this? If they didn't want us to do this they would have just said you can only replace a 2 prong with a 2 prong period! I don't believe the NEC would permit a receptacle outlet that requires the discretion of the homeowner as to what is safe and not safe to plug into it. More generally, I dont believe you can violate the NEC by plugging a UL listed product into a receptacle - this exceeds the scope of the NEC and furthermore would be impossilbe to enforce.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
electrofelon said:
What he managed to do was give her a 3 prong outlet that in itself is permitted.But it requires you place a sticker saying NO EQUIPMENT GROUND.Now the violation begins when he plugs a micro into it that REQUIRES an equipment ground

I do not agree. My thought process goes like this: We all know the purpose of equipment grounding - to deactivate the circuit if metal parts become energized, thus alerting us that there is a problem. A 2-wire GFI protected receptacle does the same thing, protects us from shocks, just in a slightly different way. The GFI wont deactivate the circuit when a frayed hot wire come in contact with a metal frame, but it will when you are grounded and touch the energized metal frame.

I don't agree that it is against code to plug a three prong plug into a three prong GFI protected ungrounded receptacle. If it was, why did they put the exception in the NEC that allows this? If they didn't want us to do this they would have just said you can only replace a 2 prong with a 2 prong period! I don't believe the NEC would permit a receptacle outlet that requires the discretion of the homeowner as to what is safe and not safe to plug into it. More generally, I dont believe you can violate the NEC by plugging a UL listed product into a receptacle - this exceeds the scope of the NEC and furthermore would be impossilbe to enforce.

Fine ,now exsplain why do we need that sticker.If it's equal why label it.What happens if the gfci fails ? Your method of thinking could get some one killed.
 

iwire

Moderator
Staff member
Location
Massachusetts
electrofelon said:
I don't agree that it is against code to plug a three prong plug into a three prong GFI protected ungrounded receptacle.

There is nothing that relives us from complying with 250.114 which basically requires that equipment with a grounding plug be connected to a grounded outlet.

It may not make sense but that is how it is.
 

iwire

Moderator
Staff member
Location
Massachusetts
charlie b said:
Jim W in Tampa said:
What you did was a violation in my opinion. You now have a piece of equipment that requires equipment ground. While she wont get killed what you did wasn't good fix
I don't agree. If an existing home does not have a conductor available to serve as an EGC, then we are permitted to install a 3-prong receptacle, and label it with "no equipment ground." I don't recall the NEC article off the top of my head, but I am confident it exists.

It does exist (the allowance to install a 3 prong receptacle on a two wire circuit) but that does not release us from 250.114.

You can not plug an appliance that requires a grounding means per 250.114 into that non-grounded GFCI protected outlet regardless of the fact the GFCI will provide some protection.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
iwire said:
charlie b said:
Jim W in Tampa said:
What you did was a violation in my opinion. You now have a piece of equipment that requires equipment ground. While she wont get killed what you did wasn't good fix
I don't agree. If an existing home does not have a conductor available to serve as an EGC, then we are permitted to install a 3-prong receptacle, and label it with "no equipment ground." I don't recall the NEC article off the top of my head, but I am confident it exists.

It does exist (the allowance to install a 3 prong receptacle on a two wire circuit) but that does not release us from 250.114.

You can not plug an appliance that requires a grounding means per 250.114 into that non-grounded GFCI protected outlet regardless of the fact the GFCI will provide some protection.

We are now left with one thing to figure out and that is just what item that has a 3 prong plug did not need equipment grounding ?They put it on and never tell us to cut it off.Plugging it in a gfci receptacle that has no ground is no differant than cutting it off.Yes its better to have a gfci than nothing but Bob IS RIGHT IT NEVER SAID TO IGNORE 250
 

iwire

Moderator
Staff member
Location
Massachusetts
Jim W in Tampa said:
We are now left with one thing to figure out and that is just what item that has a 3 prong plug did not need equipment grounding ?

Jim if you look at 250.114 it quickly becomes apparent that any equipment with a grounding cord cap must be plugged into a grounded outlet.

There really is no advantage in installing the 3 wire receptacle at all on a two wire system.

IMO the best route would be a GFCI breaker supplying the circuit and let the two wire receptacles remain.

At least in that way the homeowner would at least have a hint that plugging a grounding appliance into it may be wrong.

Of course some will do it anyway.
 

pierre

Senior Member
Bob wrote
"Jim if you look at 250.114 it quickly becomes apparent that any equipment with a grounding cord cap must be plugged into a grounded outlet."

Hence the reason for the label.

When I come across the requirements such as 406.3(D)(3), I will write in my book a reference to 250.114, so I do not forget.
 

chicar

Senior Member
Location
Lancaster,Pa
Hey fella's. Good morning.
This service call was from a friends granmother living on a fixed income He said his granma spoke of getting shocked when doing dishes. She felt she could not call a Contractor because she don't have a couple hundred to spend. When I found the proplem I went to basement to see about running a 12-2w/g to outlet.
8-circuit fuse box for service, Knob & tube wiring,no ground rod,no G.E.C., the whole house needed wiring. Someone elso took this ladies money by purposely making the homeowner and the inspector think that grounded recepticals were installed in kitchen. She said she paid 250.00 dollars for this work. The other recept was g.f.c.i. Now she has P.P.E right there to protect her and keep her from getting shocked. I also gave her my family discount. :D
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
I read the back of my microwave that i drag from job site to jobsite.It says must be pluged into a GROUNDED receptacle.Willing to bet hers says the same.While she is better off this way it was still not A legal way to supply this microwave.The lack of money forces many to take chances but that is no excuse for breaking codes.The correct repair was a hr to panel.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
IMO the best route would be a GFCI breaker supplying the circuit and let the two wire receptacles remain.


I agree with Bob, that is until the happy homeowner goes out and buys one of these:



pRS1C-2266744w345.jpg



The GFCI protection will help, but as Bob said you can't get away from the product with the 3 wire plug requiring grounding.
 
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