We are nearing the end of the series of questions about equipment labeling. I received another suggestion for a question so here it is:

Should arc flash warning labels be placed on enclosures such as wire way and larger junction boxes?

• Yes
• No
• It depends (please explain)

As we wind down this series, if you have any questions that you would like to see as part of the "Question of the Week", please let me know.

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"It Depends". Typically, wireways and junction boxes are not (or shouldn't be) accessed for "examination, adjustment, servicing, or maintenance..." (NEC 110.16). They usually have bolted covers. HOWEVER, there are instances where a j-box may have an easily accessible hinged cover. So, it becomes a "field observation" call in my view.

I also think "It Depends" This is one of those gray areas. What if you were performing some change, maintenance, addition etc. in a wire way? You do this dead/electrically safe but to verify dead you need to test voltage and this process assumes it is live until proven dead. What PPE would you wear if there is no label. I can see this spiraling out of control quickly.

Wireways typically do not have bare conductors or terminal blocks.

As for junction boxes, they may or may not have terminal blocks.

If opening the junction box affords the opportunity to expose bare live conductors, then it should have an arc flash label, but if it is in effect, just a wireway with no bare conductors or terminals, then it does not require a label in my opinion.

Larry S's words were almost identical to what I was going to say.

Junction boxes (those with splices) in my experiance have more potenial for failure than a pull box (enclosure without splices). Think of opening of a junction box with a power distribution block where various loads are tapped into a feeder cable, is this much different than opening an MCC cubical door.

Splicing in a wireway or junction box is a nightmare waiting to happen (primarily from a maintence / troubleshooting standpoint). Generally if I was going to make a splice in a junction box, I would either use a terminal strip or lugged / bolted connections.

I have seen junction boxes used for a place to make wiring changes on a frequent basis. I have also seen them never opened up. If there is going to be frequent changes or testing (especially 480V) then YES. If it is a simple controls j-box or taped connections then probably no.

Sounds like we need a definition of access frequency (more than once a year).

In my opinion, there should be Labels as the reason for opening them are to add, to check or to remove wires. Unless you have a way of proving the hazard before opening the wireway, them labels are needed. Retire with all your fingers, eh!