Bathroom GFCI with no ground?

[bud--]

Yes

Used to be code compliant up to about 10 years ago. It isn't now since existing metal in the path back to the system ground can be replaced by plastic in the future.

[Jay-T]

I want to replace an existing 2-prong receptacle in a bathroom with a GFCI receptacle. There is no ground wire going to the existing receptacle and no grounded metal cable or grounded metal outlet box -- just two separate wires, one white and one black. There is also no practical way to run a new ground wire back to the service.

In this situation, is it okay to go ahead and install the GFCI receptacle and put the sticker on it that says "No Equipment Ground"?

UP.SO. I "could" run a ground wire from the GFCI receptacle to a cold water pipe and make sure that there is a jumper across the hot water tank in and out pipes and across the water meter. But, I think I read somewhere about that being a bad idea (using the cold water pipe for a ground). That is a bad idea, right?

[Jeff The Drunk]

Yep, not a great idea.

[Jay-T]

[DerbyDad03]

Yes, it's OK to install a GFCI with no ground and mark it as such.

Since it's OK to install a GFCI with no ground, there's no need to answer your second question.

UP.SO. BTW...It's a bad idea.

[terry]

Use GFCI because it operates on the 'difference' in current between live and neutral. If someone did get a contact or drop the hair dryer in the wet metal bath tub any conseuent current likely to trip the GFCI safely.

[Mark]

-

agreed, but will the TEST button still work without a ground?

Mark

[Wayne Whitney]

Yes, as I understand it (I haven't tried it). I believe the TEST button in the receptacle allows a small current to pass from the LINE side hot to the LOAD side hot around the current transformer, thereby creating the imbalance that should trip the GFCI. In contrast a plug-in tester will not work, as it relies on the ground connection.

Cheers, Wayne

[DerbyDad03]

Yes.

The test button does not send any current to ground so no ground is required for it to work.

[Jay-T]

That's interesting. Thanks. I never would have thought of that -- the PEX or plastic replacement in the future.

[Jay-T]

Thanks. I wondered about that too.

Looks like I won't have a problem going ahead with the GFCI even though there is no ground.

[DerbyDad03]

BTW...not only is it OK to (and you should) replace the ungrounded bathroom receptacle with a GFCI, it is also code compliant to replace any 2 prong, ungrounded receptacle with a 3 pronged receptacle as long as that receptacle is protected by a GFCI and marked as having No Equipment Ground.

For example, if you have a circuit full of daisy chained 2 pronged, ungrounded receptacles, replace the first one in the circuit with a GFCI and wire all the downstream 3 prong, yet still ungrounded receptacles off of the load side.

It's a fairly common practice and allows for the use of three pronged cords in "older" homes.

[Michael Dobony]

And without a ground the GFI may not work properly.

[DerbyDad03]

Please explain.

[Twayne]

A GFCI will indeed work properly and to specs without a ground. Go read how they work and why/when they trip. Every box and most sites tell you what to do when there is no third wire. The OP had it right. Earth is NOT used in the operation of the GFCI.

if you're Canadian Google is full of good information

HTH,

Twayne

HTH,

Twayne

[Twayne]

That's correct. The "ground" in the name is NOT meaning current inside the device going to ground; it means power finding an improper path to ground, in general.

HTH,

Twayne

[Twayne]

You will be fine. If in doubt, look it up on Google or better yet, read the box sides in the store; the information is usually right on the outside of the containers.

HTH,

Twayne

[Twayne]

NO, it does NOT "allow" use of 3-wire equipment!! If a 3-wire piece of equipment is plugged into an outlet, the earth ground in that case DOES need to be present. THAT is why the outlets must be labeled as having NO ground! It's to prevent just that kind of accident waiting to happen.

HTH,

Twayne

[DerbyDad03]

Perhaps we need some clarification here.

We are talking about people protection only. We're not discussing whether the absence of a ground will be a detriment to the operation of the equipment.

It is my understanding that the GFCI will protect the user should there be current leakage to ground within the device.

If there is any type of short to ground within the device then there will be a differential between the current on the hot and the current on neutral and the GFCI will trip and the user will be protected.

Why else would the NEC allow for the use of a 3 prong outlet on an ungrounded circuit if they didn't expect you plug a 3 prong cord into it?

You'll note that code says it must be labeled as No Equipment Ground, not simply No Ground.

For the safety of us all, I won't mind if you correct me.

[do_not_spam_me]

Yes, since the test circuit is internal to the GFCI and includes an approximately 15,000 ohm resistor that connects between the device's hot and ground leads when the TEST button is pressed.

GFCIs pass the hot and neutral AC lines through the center of a transformer coil. Normally the currents in the wires are equal and opposite, resulting in no current flow in the secondary of this transformer, but when a ground fault occurs, the wires will not carry equal current, and that's why GFCI operation does not require a ground connection. In fact GFCIs are required to provide protection even without that ground.