ECN Forum Forums Code Related Discussion NEC & other Code issues Geen Wire is Not Used as an Equipment Grounding Conductor?

"GENERAL

This category covers cable investigated in accordance with International Municipal Signal Association Inc. specifications.

The cable is intended for installation as aerial cable or in underground conduit as part of a traffic signal system.

This cable employs a color-code scheme that permits a conductor with green insulation to be used for other than grounding purposes.

These cables have not been evaluated for flammability.

This cable is not suitable for use as a substitute for cable or wiring systems covered in NFPA 70, "National Electrical Code."

QUESTIONS: Why? Do these systems fall within the scope of Article 725?



[This message has been edited by Joe Tedesco (edited 06-07-2002).]

What would you bet that "green" was needed for lights of the same? Blue would have brought the system into meltdown.

At one time plain-vanilla tray and pendant cables used green and white in various combinations for conductor identification. The allowance for leaving out green and white in multiconductor assemblies is about 12 years old.

“NEMA WC57-1995/ICEA S-73-532” Table E2 (formerly K2) leaves out green and white from the list. Example at: http://www.nexans.ca/egy/equip/ultx_tc/tray22.htm http://www.drakausa.com/pdfsTAM/t10TPV.pdf http://www.sns.gov/projectinfo/ics/...0Information/Technical%20Information.pdf page 35 has both “K1” and “K2” charts.

Bjarney:

Thanks! This information is very helpful. I was always concerned about the use of the cable I described above listed by UL.

If I follow the code correctly, nowadays you can reidentify individual conductors as equipment grounds or grounded circuit conductors in a multiconductor cable, but not the reverse. If one could not use white or green for other than these under the “old” scheme, {although 600V-rated} you’d end up with lots of worthless “spares.”

Joe, this cable is commonly used by the Traffic Signal industry, and is called IMSA 19-1 (International Municpial Siganl Association, 19-1 is the cable spec).

It is a five conductor cable
White-common
Red-red display
Yelllow-yellow display
Green-green display
Black-spare, sometimes used in ped signals

Signal heads typically don't have a seperate equipment groudning conductor, but the mast arms are often connected to an EGD.

Many companies make a 19-1 cable, but I don't think a much of it is listed. I'm going to check on this. In fact very, very, little traffic signal equipment is listed. This causes problems with installations where the AHJ gets involved.

I'm a certified Traffic Signal Tech and have been writing a "Code Corner" column in the IMSA Journal for the 18 months.