Reidentifying the ground in type MC cable

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hbiss

hbiss

EC, New York NEC: 2017
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Little Falls, New York NEC: 2017
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EC
Did a walkthrough on a job earlier today. I noticed that the EC used 12/2 MC for the three- ways and reidentified the green with black tape (and only at one end!) for use as either the hot or one of the travellers. Violation? Everything else was type AC.

I have sometimes used 3 wire cable and reidentified the red as ground for IG's but this is like using the ground wire in NM for a current carrying conductor.

-Hal
 
Re: Reidentifying the ground in type MC cable

I can deal with using 12-3 mc for maybe a 3 phase motor and using blue tape,or even 12-2 to water heater and using white for a hot with tape.But if he used the green for a hot then how will he ground the device or whatever it goes to ?
 
Re: Reidentifying the ground in type MC cable

Right. After thinking about it (and to answer my own question) the armor on type MC cannot be used as an equipment ground. If you use the green ground for something else you have no equipment ground.

Violation of 250.118(11).

-Hal

[ June 02, 2004, 01:02 PM: Message edited by: hbiss ]
 
Re: Reidentifying the ground in type MC cable

Ryan, while 250.119(A) would prohibit anything under #6 from being reidentified as ground, 250.119(B) would allow it.
I believe the intent of (A) is for individual conductors pulled through raceway.

-Hal
 
Re: Reidentifying the ground in type MC cable

This may appear convoluted and I?m certainly open to a clearer reasoning.

While 200.7(B) & (C) permits re-identifying conductors normally used as grounded conductors as ungrounded conductors there is no similar permission for re-identifying conductors normally used as equipment grounding conductors as ungrounded conductors in 250-119

All conductors should be assumed to be energized until positively known to be otherwise; however, loss of the identifying method on a conductor normally used as a grounded conductor would still lead to the assumption that it is current carrying. Loss of the identifying method on a conductor normally used for equipment grounding would lead to the false assumption that it was de-energized.
 
Re: Reidentifying the ground in type MC cable

Hal,

250.119(B)is for taking a conductor and re-identifying it for use as an EGC, not for re-identifying an EGC for use as an ungrounded conductor.
 
Re: Reidentifying the ground in type MC cable

Simple:

310.2 Conductors.(A) Insulated. Conductors shall be insulated.
Exception: Where covered or bare conductors are specifically permitted elsewhere in this Code.
Click to expand...
Unless you can show where the code "specifically permits", ALL conductors (including ungrounded) must be insulated.
 
Re: Reidentifying the ground in type MC cable

Don't think 310.2 applies here. We are talking about the insulated ground conductor in MC cable being used for other than an equipment ground.

-Hal
 
Re: Reidentifying the ground in type MC cable

First off the conductor was only reidentified by the use of black tape at one termination. I have always been under the impression that you could not reidentify a EGC. I only saw in the code where they allowed you to reidentify a white or grey conductor or one that has three continous white stripes as a ungrounded conductor. 200.7 (c)
 
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