UL508A wire color code

[stevetaurus]

It was brought to my attention that UL508A had a wire color code change in the 2013 edition. I have been told that the new edition states some drastic changes from the previous release: 24VDC common, unless it is grounded, should be blue, any wire that does not turn off with the panel disconnecting means shall be orange or yellow and the neutral shall be white with orange stripe. In the case of having a UPS in the panel it seems like anything fed from the UPS would then have to follow this orange and orange/white color code. Has anyone come across this change, or are these specific to a certain type of control panel?

 

[Jraef]

It was brought to my attention that UL508A had a wire color code change in the 2013 edition. I have been told that the new edition states some drastic changes from the previous release: 24VDC common, unless it is grounded, should be blue, any wire that does not turn off with the panel disconnecting means shall be orange or yellow and the neutral shall be white with orange stripe. In the case of having a UPS in the panel it seems like anything fed from the UPS would then have to follow this orange and orange/white color code. Has anyone come across this change, or are these specific to a certain type of control panel?

These are the color codes that have been in NFPA 79 for as long as it has existed, which itself came from the older JIC standard.

The UPS angle is one I never thought of before though. Interesting, and even more so it you have a 24VDC UPS!

 

[jim dungar]

Are you sure the Orange/Yellow requirement is for internally sourced circuits that stay energized, like UPS and Caps, or is it for external sources that are not controlled by the main disconnect?

As I recall, UL 508A has some requirements for all 'general panels' and then some different requirements for panels being used in some specific machine/process panels.

 

[petersonra]

Are you sure the Orange/Yellow requirement is for internally sourced circuits that stay energized, like UPS and Caps, or is it for external sources that are not controlled by the main disconnect?

As I recall, UL 508A has some requirements for all 'general panels' and then some different requirements for panels being used in some specific machine/process panels.

this is what it actually says in the 2008 version.

66.9.1 The following color coding shall be employed throughout the panel:
a) Black – all ungrounded control circuit conductors operating at the supply voltage.
b) Red – ungrounded ac control circuits operating at a voltage less than the supply voltage.
c) Blue – ungrounded dc control circuits.
d) Yellow or orange – ungrounded control circuits or other wiring, such as for cabinet lighting,
that remain energized when the main disconnect is in the ²off² position.
e) White or gray or three white stripes on other than green, blue, orange or yellow – grounded
ac current-carrying control circuit conductor regardless of voltage.
f) White with blue stripe – grounded dc current-carrying control circuit conductor.
g) White with yellow stripe or white with orange stripe – grounded ac control circuit current carrying
conductor that remains energized when main disconnect switch is in the ²off² position.

This is what it says in the 2013 version.

66.9.1 The following color coding shall be employed throughout the panel:
a) Black – all ungrounded control circuit conductors operating at the supply voltage.
b) Red – ungrounded ac control circuits operating at a voltage less than the supply voltage.
c) Blue – ungrounded dc control circuits.
d) Yellow or orange – ungrounded control circuits or other wiring, such as for cabinet lighting,
that remain energized when the main disconnect is in the ²off² position.
e) White or gray or three white stripes on other than green, blue, orange or yellow – grounded
ac current-carrying control circuit conductor regardless of voltage.
f) White with blue stripe – grounded dc current-carrying control circuit conductor.
g) White with yellow stripe or white with orange stripe – grounded ac control circuit current carrying
conductor that remains energized when main disconnect switch is in the ²off² position.

They appear to be the same. I see no difference in the 2013 version.

Also note that it says nothing about external power. it uses the phrase "main disconnect switch is in the ²off² position" so I would say it is pretty clear that outputs from a UPS need to be color coded with yellow or orange.

incidentally, NFPA79 (2002 which is the latest I have) says this.

14.2.3.1* Where an ac circuit includes a grounded conductor,
this conductor shall be WHITE, GRAY, or three continuous
WHITE stripes on other than GREEN, BLUE, ORANGE, or
YELLOW insulation along its entire length.
14.2.3.2 The use of other colors for the following applications
shall be as follows:
(1) WHITE with BLUE stripe for grounded (currentcarrying)
dc circuit conductor.
(2) WHITE with ORANGE stripe or WHITE with YELLOW
stripe for grounded (current-carrying) circuit conductor,
which remains energized when the main disconnecting
means is in the off position.
(3) Whichever color stripe is selected, that color stripe shall
be consistent with the ungrounded conductor of the excepted
circuit described in 5.3.5.

So neither of them says anything about "external" power.

 

[Jraef]

True, nothing says "external".

Also, just as a cautionary note by the way...

Most UPS units will be listed under UL1778. In the UL508a rules, UL1778 is not one of the associated standards that are allowed to be incorporated into a listed panel assembly. That has typically resulted in the UPS being located OUTSIDE of the listed panel assembly, in which case the color coding would be as per usual for external circuits (er... circuits not disconnected by the main...) anyway.

That said, read a post (link) I put up here in 2011. As far as I know, nothing has changed yet with UL.

 

[petersonra]

I had a chat once with a UL engineer. One of the things he told me was that in essence if the standard itself says it can be used in a UL508a panel it is Ok to use it there even if it is not in the list of acceptable parts in the UL508a standard itself.

I don't recall offhand what I had specifically asked about though. It is possible it has since been added to UL508a.

You can also add things to your own version of UL508a that don't apply to anyone else unless they also pay to have it added to their "procedure".

For instance, I understand that AB (or maybe one of its contracted panel shops) has some kind of procedure that allows them to use at least some things that are listed for switchboards in their UL508a panels, but that are not listed in UL508a specifically.