There are a number of 100 Amp 600V fusible disconnects that were installed on a project. They had installed a round type of voltage indicator (approx. 2" diameter)onto the front face of the switches. The wiring is then secured to the inside of the door with slack and goes to the Line terminals.
My concern is, are we allowed to mount anything on a door? A lot of people did not see anything wrong with it. I don't like it, and was looking for some code articles that I could hit them with. I never installed anything on the door of a disconnect. Thanks

Modifications to the enclosure (door, etc.) IMHO would be an issue with the UL listing/labeling. Also, I would have an issue with the volt indicators being on the 'line' side; is there any OCP? How are the terminations of the meter leads made on the 'line' side. What purpose were the voltage indicators installed for?

Thanks John,
I don't think it flies with UL. They were installed in the field. I have to check, if there is fuse protection for the meters. The terminations cannot go under the same lug. I want to check that.
They are using them for a fast visual to determine voltage presence.
When I find out, I'll let you know
Good Day - Steve

The set-up seems poorly thought out. One would want the leads to go to the LOAD terminals so that blown fuses -- and single phasing -- would show up.

Further... Is this out in the open? NEMA 3R?

Are you dealing with 1-phase or 3-phase power?

It's hard to see how meter leads would NOT foul up safe access to the fuses.

Tesla,
Three-phase, indoor, and they want the leads on the Line side. Large experimental hallway. I agree, the wiring could be in the way.
To be continued, Thanks -SJT