color code

[mbarry]

Hello,
I work for a company which designs and builds control panels per UL508A. We have difference of opinion here concerning what color to run a specific wire.
Motor control circuit is being supplied by 120vac control transformer with grounded secondary. NC contact of overload relay is located on grounded circuit conductor side of contactor coil. What color wire should be run between overload contact and coil.
Is this still considered a grounded circuit conductor after it passes through NC contact of overload and should be continued with white wire? or should it be considered part of the 120v circuit and run with red wire.
UL508A is not clear on this.
Normally we would locate overload contact on ungrounded side of coil,but in this case we are using customer drawings.
Thank you for any insight anyone can provide on which is correct or common practice.

 

[tony_psuee]

mbarry,

In the same situation, I have used a white wire. Because as you stated, it is on the grounded side of the circuit. What I have seen cause more problems is drawings that show OLR wired as you described or as your normal practice and the circuit is actually wired opposite with no change in the wire color, use red for grounded or white for ungrounded. :x

Tony
If God isn't a Penn State fan, then why is the sky blue and white?

 

[mbarry]

Tony,
Thanks for the response. I agree. I also have been running it white in the past. But, we have some new engineers here who are claiming it should be red. I think this just confuses the issue. I was just hoping to get a consensus on what other people are doing in this situation. Or better yet, if anybody knew of any reference material where this addressed
(which I doubt)

 

[Brinkmann]

Good Question...before the O/L ( from A2 to the O/L) we use red. On the other side of the O/L we use white.

 

[petersonra]

a lot of people have resolved this problem by putting the OL on the hot side of the coil.

of course you can't do this with a reversing starter.

 

[jim dungar]

Color coding of wires internal to control cabinets is covered both in NFPA79 and UL508A.

UL508A (66.5) says in "industrial machinery" control panelsl all ungrounded power conductors shall be black, and all grounded AC conductors shall be white or grey. 66.9.1 covers the control wires: Black all ungrounded conductors at supply voltage, Red all ungrounded AC conductors at less than supply voltage, Blue all ungrounded DC conductors, White or Gray all grounded AC, and White w/Blue stripe all grounded DC conductors.

Every control panel wiring reference I have found says "if the conductor is grounded then it needs to be white".

 

[mbarry]

Jim,
I agree. The difference of opinion is wether or not this wire is considered a grounded conductor.

 

[jim dungar]

OOPS

I just went back and reread your original question, I have been looking at the wrong wire.

IMHO
One end of wire is directly connected to coil (not ground) other end of wire is directly connected to one OLR contact (not ground), therefore this is not a grounded conductor and should not be white.

For what it is worth, every major manufacturer of UL listed NEMA style starters uses a colored wire in this application.

 

[bassphisher]

I ran into this a lot myself also and for what its worth heres my opinion.

After the coil the wire should be white if their are no other loads in series besides the over loads.
Here is my reasoning if you check voltage on the a2 side of the coil their will be no voltage to neutral or ground.Since their is no potential difference the wire is neutral and should be white,even though the overloads are in series with this wire.
Paul
Electrical Inspector