Equipment serviced by seperate disconnecting means?

[Chev]

I have a nagging thought running through my head that tells me: "you can not feed more than 1 piece of equipment from a single disconnect." But I can not find any documentation to back my memory.
Scenario is, a small drill press and a grinder mounted side by side. The guys on the job want to come out of an altered interlocking weld plug disconnect (plug removed and replaced with a sheet metal "patch") and feed (480 volts) both pieces of equipment from the one disconnecting means.
I question the alteration of the weld plug disconnect, and the feed of 2 pieces of equipment from 1 disconnecting means, but am searching NFPA 70, 70E, 79, and SAE Stds. for Automotive Industrial Machinery and I can find nothing to say "they can't do that". Helpppppppppp! :-?:grin:

 

[zbang]

The first question is whether the (former) welding circuit is correcctly sized for the new load (see Art 630). Because it was a welding circuit, the conductors might be smaller than he breaker size would indicate (say, 12g on a 30a breaker), so using this for something else could easily be a violation. The next quistion is whether the manufacturers require a dedicated power feed to their equipment.

Also, look at Art 430 on motors.

If the conductors match the OCPD, and you run that same size all the way out to the equipment (you can't downsize along the way), then it might be OK.

 

[Jraef]

...Also, look at Art 430 on motors.

If the conductors match the OCPD, and you run that same size all the way out to the equipment (you can't downsize along the way), then it might be OK.

That's the key, plus the issue of being within line of sight to both machines. Unless the machines don't have their own OCPDs, in which case you also have to deal with that issue and then the "jury rig" may end up being a moot point.

For example, a 1/2HP drill press and a 1HP grinder, both a 480V. The max. OCPD for the 1HP is going to be twice the size of the 1/2HP, but if you size the single OCPD for the 1/2HP, the 1HP may blow the fuses. If you use a CB, then 15A is the smallest anyway and if each machine has it's own OL relay, it might be OK. Bottom line, lots of "IFs".

 

[zbang]

Oh.... if all the sizes are correct, you still won't be able to run both at the same time..

And somehow I just can't think of a 480v drillpress as 'small', but maybe I don't get out enough.

 

[Chev]

I was misinformed, I went out and looked for myself and found a sander that is 3 phase 480 volts drawing 2.5 amps, and a grinder that someone had hooked up :roll: 2 phase 208 but was "running" on 3 phase 480 and the guys on the job hadn't noticed it...now we have a whole new kettle of fish! They're going back to the drawing board!
Thanks for the help all! At least I learned something from this!