# Where do you stop?



## crwilliams (Oct 26, 2012)

I was recently asked to replace some early 1950s non-polarized two prong outlets with current three-prong tamper resistant devices to improve safety. The wiring was metal clad, and that cladding was grounded. The boxes were galvanized steel mortared in to masonry. So it looked relatively straightforward. The first one I looked at had black & white wires, as expected, but the white was hot and the black was grounded (neutral). I checked the othets and found the same wiring and polarity inversion. So what would you do? Would you continue with the outlet replacement, increasing safety over the existing two-prong setup, ensuring the outlet had narrow slot hot, wide slot neutral? (In other words, if you didn’t look at the wires behind the faceplate you wouldn’t know there was an issue.)

The metal clad wiring is buried in masonry walls and it’s a far more expensive job to figure out what is going on and where the polarity color inversion is happening. It’s a large, older building used for religious purposes. It’s also quite possible that later work on the wiring elsewhere has ‘corrected’ the polarity somewhere by splicing old white to new black…


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## Almost Retired (Sep 14, 2021)

i have seen that once or twice
it was backwards in the panel (white on the breaker)
swap all the wires and see if polarity stays with correct color is best i can offer

how are you going to attach the ground to the plug ?
have you ohmed the ground for low resistance all the way to the panel ?

if you dont have very low resistance it should be a GFCI plug if you want it safe
if you are replacing plugs for the whole house, i would correct the polarity/colors
then you have to check the switches to see whether they end up switching the neutral

i know u already bid the job, but something to think about next time maybe ?


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## crwilliams (Oct 26, 2012)

Almost Retired said:


> i have seen that once or twice
> it was backwards in the panel (white on the breaker)
> swap all the wires and see if polarity stays with correct color is best i can offer
> 
> ...


Thanks for taking time to comment. Not the whole building - just three outlets in one room, hence reluctance to change anything without checking everything else in the building. Yes, low resistance from boxes through BX/MC to panel. So it measures safe and the outlets have the correct polarity: just the wire colors wrong.


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## Almost Retired (Sep 14, 2021)

crwilliams said:


> Thanks for taking time to comment. Not the whole building - just three outlets in one room, hence reluctance to change anything without checking everything else in the building. Yes, low resistance from boxes through BX/MC to panel. So it measures safe and the outlets have the correct polarity: just the wire colors wrong.


how will you attach the ground wire to the plug and the bx ?
what is low resistance ? less than 1 ohm ?


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## crwilliams (Oct 26, 2012)

The BX goes through a listed screw clamp into the box. I’m getting under 0.5 Ω on my Fluke. Was planning to use COTS grounding pigtails from the outlet ground, other end screwed into the metal box.


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## kb1jb1 (Nov 11, 2017)

I have seen several houses where the white was hot. My father warned me about it on older houses. Remember " no good deed goes unpunished" . You could switch it but you might create a problem elsewhere. If someone bootlegged a ground somewhere and you switched the wiring to what we are accustomed to, you could send the new hot to a grounding terminal. Also the armor on some older AC or BX is not approved for grounding. It technically needs that thin aluminum bonding strip. Maybe keep the wires as they are and just mark them with white tape on the actual grounded conductor and red or blue on the hot. I know we are not supposed to mark small wires but to me it is the safer option. Mark the panel likewise for the next guy.


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## Forge Boyz (Nov 7, 2014)

I've also heard of guys switching the black and white when the black was shorted to ground. They figure since the nuetral is grounded any its ok.

Sent from my SM-G970U using Tapatalk


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## dspiffy (Nov 25, 2013)

I would get some white and black electrical tape, do the job, and forget about it.


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## BleedingLungsMurphy (10 mo ago)

dspiffy said:


> I would get some white and black electrical tape, do the job, and forget about it.


Are you allowed to tape # 14 down south? That would be a code violation here. I would pig tail the correct color to the receptacles with some new wire and try not to disturb the old wiring too much.


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## canbug (Dec 31, 2015)

Your in for a bit of work however you tackle this. Being a church, you may be doing this as a favour but you need to talk to the money person and explain what you found, how to fix it properly, how long this may take if you are only stopping in once and awhile, what if any compensation you may be looking for if it ends up being a big job.
Good luck.

Tim.


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## dspiffy (Nov 25, 2013)

BleedingLungsMurphy said:


> Are you allowed to tape # 14 down south? That would be a code violation here. I would pig tail the correct color to the receptacles with some new wire and try not to disturb the old wiring too much.


I believe it's required to mark any white wire used as hot (above 50v) with black tape. Not sure about black used as neutral because I've honestly yet to run across that.


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## Almost Retired (Sep 14, 2021)

dspiffy said:


> I believe it's required to mark any white wire used as hot (above 50v) with black tape. Not sure about black used as neutral because I've honestly yet to run across that.


it can also be done with a black marker on white, i also have seen a red marker used for 220V


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## BleedingLungsMurphy (10 mo ago)

Code violation in Canada. We can only tape #2 or larger. Anything smaller and we are suppose to order the correct color.


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## crwilliams (Oct 26, 2012)

canbug said:


> Your in for a bit of work however you tackle this. Being a church, you may be doing this as a favour but you need to talk to the money person and explain what you found, how to fix it properly, how long this may take if you are only stopping in once and awhile, what if any compensation you may be looking for if it ends up being a big job.
> Good luck.
> 
> Tim.


Thanks Tim - you understand completely!


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## splatz (May 23, 2015)

The NEC doesn't allow you to re-identify small wires white for the neutral



> 200.6 Means of Identifying Grounded Conductors.
> (A) Sizes 6 AWG or Smaller. An insulated grounded conduc‐ tor of 6 AWG or smaller shall be identified by one of the following means:
> (1) A continuous white outer finish.​(2) A continuous gray outer finish.​(3) Three continuous white or gray stripes along the conductor's entire length on other than green insulation.​(4) Wires that have their outer covering finished to show a white or gray color but have colored tracer threads in the braid identifying the source of manufacture shall be considered as meeting the provisions of this section.​(5) The grounded conductor of a mineral-insulated, metal-sheathed cable (Type MI) shall be identified at the time of installation by distinctive marking at its terminations.​(6) A single-conductor, sunlight-resistant, outdoor-rated cable used as a grounded conductor in photovoltaic power systems, as permitted by 690.31, shall be identified at the time of installation by distinctive white marking at all terminations.​(7) Fixture wire shall comply with the requirements for grounded conductor identification as specified in 402.8.​(8) For aerial cable, the identification shall be as above, or by means of a ridge located on the exterior of the cable so as to identify it.​*(B) Sizes 4 AWG or Larger. An insulated grounded conductor 4 AWG or larger shall be identified by one of the following means: *
> (1) A continuous white outer finish.​(2) A continuous gray outer finish.​(3) Three continuous white or gray stripes along the conductor's entire length on other than green insulation.​*(4) At the time of installation, by a distinctive white or gray marking at its terminations. This marking shall encircle the conductor or insulation. *​


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## Veteran Sparky (Apr 21, 2021)

canbug said:


> Your in for a bit of work however you tackle this. Being a church, you may be doing this as a favour but you need to talk to the money person and explain what you found, how to fix it properly, how long this may take if you are only stopping in once and awhile, what if any compensation you may be looking for if it ends up being a big job.
> Good luck.
> 
> Tim.


Absolutely...I stay away from churches because they receive their income from donations.


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## baddoggy (7 mo ago)

If there is no dedicated bonding conductor then I would recommend using gfci receptacles. At the very least change the polarity from the first replacement to the remaining plugs. However I would want to trace it back to wherever the polarity was switched. It could save a life. Who knows what else you will find. Where to stop is when the wiring is safe. I had to rewire a house because a diy started messing around and the wiring was insulated with natural rubber and it disintegrated as soon as it was disturbed. There was no going back after that.


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## macmikeman (Jan 23, 2007)

When the outer metal wrap of bx is used as a ground and then there is a fault to ground, that spiral wrap which has resistance can start acting just like a heating coil in a heater appliance. I have seen red glowing ones before so watch out for that . A normal circuit breaker doesn't know the difference from this to a space heater. A gfi placed at the closest place near the start of the circuit or else right at the breaker is your best way to combat this.


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## baddoggy (7 mo ago)

macmikeman said:


> When the outer metal wrap of bx is used as a ground and then there is a fault to ground, that spiral wrap which has resistance can start acting just like a heating coil in a heater appliance. I have seen red glowing ones before so watch out for that . A normal circuit breaker doesn't know the difference from this to a space heater. A gfi placed at the closest place near the start of the circuit or else right at the breaker is your best way to combat this.


I agree. I don’t like those tin grounds. Better than nothing as long as you’re sure things are tight and no corrosion.


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## macmikeman (Jan 23, 2007)

baddoggy said:


> I agree. I don’t like those tin grounds. Better than nothing as long as you’re sure things are tight and no corrosion.


I don't agree. I think it's better to float that spiral skin and just use 2 wire outlets cause of that wrap getting red hot. And I mean hot.


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## Slay301 (Apr 23, 2018)

I would walk away unless it’s probably fixed. Correct me if I’m wrong. If you swap it and some how miss one in the circuit wouldn’t that creat a short ckt ? Maybe just put a gfci in instead


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## paulengr (Oct 8, 2017)

dspiffy said:


> I would get some white and black electrical tape, do the job, and forget about it.


Not a good idea. You can’t reidentify that size. This is a case of you break it you own it or two wrongs don’t make a right.

What you do is offer to fix the wiring too . I would offer up that some older BX has been known to have serious issues and the damaged black theory. But I’d verbally explain the black/white issue and what’s involved in fixing it. Let the HO decide if it’s worth it compared to a couple hours labor:

We make decisions like this all the time. Wrong colors is a normal thing for me. I do mostly industrial: Everything can be any color. You have to get good at recognizing function: Yesterday I think we identified 3 or 4 circuits (still not sure) that changes colors 3 or 4 times: Bear in mine this is for quite literally just a simple start/stop 3 wire circuit with 3 interlocks. No dra Inge of course and all panels were rats nests with everything floating around instead of tie wrapped and screwed or in wire duct.


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