can a ground be used as a neutral?

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  #1  
Old 10-16-13, 09:19 AM
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can a ground be used as a neutral?

A hypothetical question:
If I have a switchbox with a single switchleg 14-2WG and a switch inside BUT I want to add a 2-prong outlet for a plug-in nightlight can the ground be taped and re-identified as a neutral at both ends in order to not have to abandon the cable and run new?
 
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Old 10-16-13, 09:31 AM
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No. You need to run a new cable.
 
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Old 10-16-13, 09:36 AM
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No, grounds cannot be re-purposed.

Edit: Whoops, looks like Tolyn beat me to it.
 
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Old 10-16-13, 11:52 AM
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Absolutely not. You run the risk of electrifying parts of your system and creating a serious shock hazard.
 
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Old 10-16-13, 12:28 PM
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You run the risk of electrifying parts of your system and creating a serious shock hazard.
Sounds like a scare tactic answer. I accept it's not code today but I have seen this in 2 past homes so was it EVER OK to do this?
 
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Old 10-16-13, 12:45 PM
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No scare tactic, just logic. It has never been approved to repurpose a grounding wire to a neutral. Like mom said.....just because Johnny did it........doesn't make it right.:NO NO NO:
 
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Old 10-16-13, 12:46 PM
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No.

.
 
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Old 10-16-13, 02:06 PM
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No it is not a scare tactic. It is not permitted under the code.

The answers given on this board will be in compliance with established codes and standards. You will not get incorrect information or "hey it works" type answers here.
 
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Old 10-17-13, 10:24 AM
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Sounds like a scare tactic answer. I accept it's not code today but I have seen this in 2 past homes so was it EVER OK to do this?
Never has been code and never will be code; the NEC is all about safety.
 
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Old 10-17-13, 02:20 PM
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How far back does The Code go?
 
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Old 10-17-13, 03:12 PM
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The first electric code was started in 1897
 
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Old 10-17-13, 04:00 PM
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So any wiring prior to 1897 may be grandfathered.
 
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Old 10-17-13, 06:16 PM
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A hypothetical question:
If I have a switchbox with a single switchleg 14-2WG and a switch inside BUT I want to add a 2-prong outlet for a plug-in nightlight can the ground be taped and re-identified as a neutral at both ends in order to not have to abandon the cable and run new?
Aside from agreeing with the others --- if you were to repurpose that grounding conductor you would be removing the EGC for that branch circuit ( the switch box & switch ) which I believe would be another code violation.
 
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Old 10-17-13, 07:13 PM
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Dont get me wrong, I understand that per code other wires can be re-purposed but the green wire is sacred. What I have never seen explained is why its OK to have a house with NO grounded outlets, but not OK to repurpose that 3rd conductor that isn't serving any purpose.

The house I grew up in had some 2-conductor NM and some with ground...but not a single grounded outlet. Did the code in 1950 say to ground all boxes to the panel but dont ground outlets and appliances? Now we have plastic boxes and we're safer?
 
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Old 10-17-13, 09:26 PM
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I understand that per code other wires can be re-purposed
Under certain circumstances, in the U.S., a wire with white insulation that is part of a cable assembly may be redesignated as an ungrounded conductor. No other conductor may be. See 120/240V Wiring Color Code Interpretation.

but the green wire is sacred.
The green wire or, more commonly, the bare conductor, isn't sacred. It's separate. A complete hot-to-neutral circuit consists of an ungrounded conductor, a load, and a neutral. The equipment grounding conductor isn't part of it. It's there to provide a low-impedance path to ground in the event of a fault. It functions as an emergency overflow drain.

What I have never seen explained is why its OK to have a house with NO grounded outlets,
It isn't really OK. It's not allowed in new construction, including remodeling. It should only exist today where an older system has remained in service without being upgraded.

but not OK to repurpose that 3rd conductor that isn't serving any purpose.
The industry considers significantly reducing both the risk of shock and the risk of fire to be worthwhile purposes. The code reflects this.

The house I grew up in had some 2-conductor NM and some with ground...but not a single grounded outlet.
Any device mounted to a metal box that is bonded to ground is thereby bonded to ground. That's still allowable practice today.

If you're saying that the house didn't have any 3-slot receptacles, the work may have been done before those were adopted. It's unlikely that anyone would have invested the time and expense to run 2-conductor, 3-wire cable and not have installed those if they were available.

Did the code in 1950 say to ground all boxes to the panel but dont ground outlets and appliances?
No. Bonding and grounding requirements were expanded to include the EGC sometime in the 1960s.

Now we have plastic boxes and we're safer?
I install metal boxes and bond them to ground, but that's just a personal preference. Non-metallic electrical boxes have a proven safety record dating from before WWII.
 
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Old 10-18-13, 07:23 AM
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So prior to the code change in the 60's grounded cable was available and it was up to the installer how to apply it safely?

I've always wondered if the weird stuff I saw in the first 2 old houses I grew up in was done by hacks or if it was allowable practice back then.

I wouldn't re-purpose a ground conductor any more than I would use knob-and-tube today, but apparently both had their place in time.
 
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Old 10-18-13, 07:32 AM
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Actually correctly installed K&T would be safe even today. Some might argue slightly safer. It is not used because of the difficultly installing it correctly.
 
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Old 10-18-13, 10:44 AM
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So prior to the code change in the 60's grounded cable was available and it was up to the installer how to apply it safely?
I'm not sure it was available. It certainly wasn't commonly available. I don't recall seeing any in older installations.

In general, the manufacturing sector of the industry doesn't develop innovative products and bring them to market before they're required, and never before they're approved. If they think of something that they believe will make the work easier and safer, they may develop a prototype, and even patent it. Then they'll lobby the committees that revise the code to agree that their innovation has merit. Production begins once it's clear that the new product meets or exceeds the code requirements and it has been approved by a recognized testing organization such as Underwriters Laboratory.

It has always been the responsibility of the installer to do the work in a safe and effective manner. That's why we have to be licensed.

I've always wondered if the weird stuff I saw in the first 2 old houses I grew up in was done by hacks or if it was allowable practice back then.
Originally Posted by Nashkat1
Any device mounted to a metal box that is bonded to ground is thereby bonded to ground. That's still allowable practice today.

If you're saying that the house didn't have any 3-slot receptacles, the work may have been done before those were adopted. It's unlikely that anyone would have invested the time and expense to run 2-conductor, 3-wire cable and not have installed those if they were available.
There's no evidence that the installation wasn't done in compliance with best practices at the time.

I wouldn't re-purpose a ground conductor any more than I would use knob-and-tube today, but apparently both had their place in time.
Originally Posted by ray2047
Actually correctly installed K&T would be safe even today. Some might argue slightly safer. It is not used because of the difficultly installing it correctly.
In the early 1980s, my ex and I renovated a wonderful old house for our family. When it was built in 1908 it had a dual-fuel lighting system installed. The wiring for the electrical part was all knob-and-tube, of course.

I left a few sections of the old K&T in place and used it as part of the new 200A codes-or-better system. Mostly switch legs and other stuff in walls that didn't otherwise need to be opened and were difficult to fish in. It probably took me an hour or more to make up each junction box when I wanted to do that.

I made sure my inspector got an up-close and personal view of every splice on that job - especially the ones transitioning to and from the K&T. Everything passed on first inspection. So far as I know, it's still in use today.
 
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Old 10-18-13, 04:27 PM
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Grounding conductors in NM cable started in the early 60's. Before that the NEC did not require it. Cable commonly called BX had a bond conductor that allowed the metal sheath to be used as a ground. The boxes were grounded through the cable.

Plastic boxes do not require grounding since there are non-conductive.
 
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