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Old 12-16-2012, 12:12 AM   #1
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ground wires...


i have a ceiling llight box (the metal box that the romex goes in i dont know the techical name of it) anyway the wires that go into it that my light wires up to doesnt have a ground wire. its an old house with just 2 wires. would it be ok to run another length of romex up to the ceiling box, pigtailing the ground wire from one end of the romex wire from the plug outlet just for the use of the ground wire?


im looking to run a ground wire off of another ground wire using a length of romex..

hope this makes sense

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Old 12-16-2012, 07:15 AM   #2
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A piece of Romex to a nearby grounded receptacle will not suffice as a ground (provide an equipment grounding conductor) unless the power for the light fixture also came through that piece of Romex.

In addition (you mentioned that the house is fundamentally 2 wire), the box with the receptacle and its feed must have been upgraded (or newly installed) so as to be grounded.

Technically you may not add things onto a circuit that is not compliant for example is not grounded. So you really may not add the light fixture to an existing ungrounded circuit but rather would have to string a new circuit up from the panel.

Now you can run a separate ground wire from the item you want grounded all the way down to the panel, exactly, approximately, or vaguely following the route of the circuit conductors feeding that item. This separate EGC may or may not be in a piece of Romex but if it is, you might as well run it as a brand new circuit.

Generally you may leave existing ungrounded light fixtures ungrounded until you are ready to upgrade the circuits feeding them. They don't get touched a lot so as to make you concerned about electrocution although it is a good idea to flip off the breaker before changing the lamp (bulb).

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Last edited by AllanJ; 12-16-2012 at 07:20 AM.
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Old 12-16-2012, 07:29 AM   #3
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Quote:
Originally Posted by AllanJ View Post
A piece of Romex to a nearby grounded receptacle will not suffice as a ground (provide an equipment grounding conductor) unless the power for the light fixture also came through that piece of Romex.

In addition (you mentioned that the house is fundamentally 2 wire), the box with the receptacle and its feed must have been upgraded (or newly installed) so as to be grounded.

Technically you may not add things onto a circuit that is not compliant for example is not grounded. So you really may not add the light fixture to an existing ungrounded circuit but rather would have to string a new circuit up from the panel.

Now you can run a separate ground wire from the item you want grounded all the way down to the panel, exactly, approximately, or vaguely following the route of the circuit conductors feeding that item. This separate EGC may or may not be in a piece of Romex but if it is, you might as well run it as a brand new circuit.

Generally you may leave existing ungrounded light fixtures ungrounded until you are ready to upgrade the circuits feeding them. They don't get touched a lot so as to make you concerned about electrocution although it is a good idea to flip off the breaker before changing the lamp (bulb).
If you install a piece of romex from recepticle to the light for the ground that would acceptable. Wire nut the black and white. This wire could be claasified for future use, but using the ground wire at this time.
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Old 12-17-2012, 09:12 AM   #4
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without running new wire from the panel to the light, is there a way to add a ground wire?

let me rephrase my question.
im using the existing 2 wire ceiling light (no longer using the actualy ceiling light) to power an outlet instead.

is there a way to ground the outlet without running new wire to the panel?

Last edited by echobravo; 12-17-2012 at 10:59 AM.
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Old 12-17-2012, 05:21 PM   #5
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Quote:
Originally Posted by echobravo View Post
i have a ceiling llight box (the metal box that the romex goes in i dont know the techical name of it) anyway the wires that go into it that my light wires up to doesnt have a ground wire. its an old house with just 2 wires. would it be ok to run another length of romex up to the ceiling box, pigtailing the ground wire from one end of the romex wire from the plug outlet just for the use of the ground wire?


im looking to run a ground wire off of another ground wire using a length of romex..

hope this makes sense
Install a GFCI breaker and call it good.
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Old 12-17-2012, 05:34 PM   #6
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You used to be able to run an 'extra' ground wire, but the 2011 code changed this (or was it 2008).

New code is to install a GFCI outlet leaving the ground unconnected, or as stickboy said, put in a GFCI breaker. The breaker is better as it will protect the whole circuit, not just that outlet.

Note, this will not provide a ground for electronics, but should protect against shocks / electrocution.
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Old 12-17-2012, 06:07 PM   #7
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Article 250.130 was not changed. It still allows a EGC to be run to ground to older wiring.
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Old 12-17-2012, 07:41 PM   #8
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You used to be able to run an 'extra' ground wire, but the 2011 code changed this (or was it 2008).

New code is to install a GFCI outlet leaving the ground unconnected, or as stickboy said, put in a GFCI breaker. The breaker is better as it will protect the whole circuit, not just that outlet.

Article 250.130 was not changed. It still allows a EGC to be run to ground to older wiring.

I got a little confused; I must be tired or missed something.
So can I run a single ground wire from the panel to an outlet on a two wire circuit?
Also on a GFCI outlet leaving the ground unconnected cause the GFCI trip.
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Old 12-17-2012, 07:49 PM   #9
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Thanks guys, I'll go read it again. I do my best to be correct but I am glad you have my back!

Ok, so a new EGC has to go back to the panel, right?

Or a GFCI will meet code.

So who wants to explain how a GFCI works without a ground. I'm willing to give it a go!
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Old 12-17-2012, 07:55 PM   #10
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There are a couple of acceptable places to connect the new EGC for the old 2 wire circuit. The panel where the circuit originates is one place.

The GFI measures the difference in current between the hot and neutral. If it is off by 5 mA the GFI will trip.
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Old 12-17-2012, 08:07 PM   #11
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Quote:
Originally Posted by TTW View Post

So who wants to explain how a GFCI works without a ground. I'm willing to give it a go!
The device doesn't measure anything on a EGC, just the hot and neutral conductor....
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Old 12-17-2012, 08:07 PM   #12
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250.130 Equipment Grounding Conductor Connections.
Equipment grounding conductor connections at the source
of separately derived systems shall be made in accordance
with 250.30(A)(1). Equipment grounding conductor con-
nections at service equipment shall be made as indicated in
250.130(A) or (B). For replacement of non–grounding-type
receptacles with grounding-type receptacles and for branch-
circuit extensions only in existing installations that do not
have an equipment grounding conductor in the branch circuit,
connections shall be permitted as indicated in 250.130(C).

(A) For Grounded Systems. The connection shall be
made by bonding the equipment grounding conductor to
the grounded service conductor and the grounding elec-
trode conductor.
(B) For Ungrounded Systems. The connection shall be
made by bonding the equipment grounding conductor to the
grounding electrode conductor.
(C) Nongrounding Receptacle Replacement or Branch
Circuit Extensions. The equipment grounding conductor
of a grounding-type receptacle or a branch-circuit extension
shall be permitted to be connected to any of the following:

(1) Any accessible point on the grounding electrode sys-
tem as described in 250.50
(2) Any accessible point on the grounding electrode con-
ductor

This is where the building is grounded at the main panel

(3) The equipment grounding terminal bar within the en-
closure where the branch circuit for the receptacle or
branch circuit originates
(4) For grounded systems, the grounded service conductor
within the service equipment enclosure
(5) For ungrounded systems, the grounding terminal bar
within the service equipment enclosure
Informational Note: See 406.4(D) for the use of a ground-
fault circuit-interrupting type of receptacle.



(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).
(a) A non–grounding-type receptacle(s) shall be per-
mitted to be replaced with another non–grounding-type re-
ceptacle(s).
(b) A non–grounding-type receptacle(s) shall be per-
mitted to be replaced with a ground-fault circuit interrupter-
type of receptacle(s). These receptacles shall be marked
“No Equipment Ground.”
An equipment grounding con-
ductor shall not be connected from the ground-fault circuit-
interrupter-type receptacle to any outlet supplied from the
ground-fault circuit-interrupter receptacle.
(c) A non–grounding-type receptacle(s) shall be per-
mitted 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.
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Old 12-17-2012, 08:48 PM   #13
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AC power flows in two directions, from hot to neutral, then from neutral to hot, it switches directions back and forth 60 times a second. Think of a lamp with a two prong connector, it doesn't need a ground to light up.

The GFCI senses the amount of current going in one direction and compares it to the amount of current going the other way. It does this very well.

So lets say that lamp had an electrical leak and you touched it. You are wearing sneakers and are not touching anything else. You would not get a shock because there is no path through you to anywhere the electricity might go.

Then you touch a metal water pipe and zap you get shocked. Why? because some of the electricity found an easier way through you to do what it really likes to do, to return to it's source, the transformer at the pole (usually through the ground).

Lets say the lamp was grounded and a nasty short developed. That power would head off to ground lickety split and suddenly instead of the power draw of a light bulb, a whole lot of power is flying through the circuit breaker. So much power that the circuit breaker says Pull Over! and trips and the circuit goes dead.

Now lets say the lamp (not grounded again) has a small leak of current, not so much that the breaker trips, or maybe the breaker malfunctions, and you touch it again and grab that handy water pipe and you get badly shocked or worse.

OK, long winded I know, gotta lay off the coffee...

So now we plug our 2 prong ungrounded lamp into a GFCI

The GFCI says, lets see, I got 833.7 mili-Amps going this way and 833.1 mA going that way, no problem... Allright 831.4 mA - 832.2 mA Okee Dokee.... You get the idea...

and you touch the lamp and the water pipe again (why you would do this again I don't know).

Now the GFCI sees 829.0 mA - 834.2 mA AND SAYS WOHA NELLIE!!!!!! Theres 5.2 mA MISSING !!!!!!

I don't know where it's going, I don't care if it's going to Jupiter through the CAT! I just know that it's going SOMEWHERE it's not supposed to !!!!!

and the GFCI trips and saves your life. No ground required. They say these things trip so fast, you probably will feel a shock, but it won't kill you.

They are designed to trip at 5/1000 of an amp, that's 0.005 amps. A 100 watt light bulb only draws draws about 8/10 or 0.08 amps (or about 16 times more power) just to give you an idea.

Whew, I'm getting another coffee!
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Last edited by TTW; 12-17-2012 at 11:29 PM. Reason: Got schooled a little. It's good to learn stuff!
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Old 12-17-2012, 09:12 PM   #14
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Few fixes in your long winded explanation, first off electicity does not seek the ground/earth, it returns to the source, which is the transformer at the pole. Secondly, you will feel a shock from a gfci, but you will most likely live.
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Old 12-17-2012, 10:08 PM   #15
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Got it

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