Control panels used as raceways

[Glenn Becnel]

I would appreciated some help with an issue I recently observed. An A/C contractor on a new construction project apparently installed a conduit into the wrong piece of equipment (A/C Chiller Unit control panel). The problem was conpounded when he installed another conduit from the same control panel to the correct equipment. He has pulled the wire (low voltage) through the control panel (contains 480V). Wires in these two conduits are not terminated in the control panel. He is using the panel as a pass-through. Where can I find this violation in the NEC?
Thanks in advance for your help.

 

[bphgravity]

Re: Control panels used as raceways

Enclosures, including control panels, are generally permitted to be used as raceways. The requirements are found in 312.8. Conductors of different systems are also permitted to share the same enclosure if the meet the rquirements of 300.3(C)(1).

However, I am not sure what you mean by "low voltage" systems? Perhaps your are talking about class 2 or 3 circuits. If so, Artcile 725 must be reviewed.

 

[steve66]

Re: Control panels used as raceways

I would reject this based on 300.3(C) unless he can show that the low voltage cable is rated for 480 volts. There may be some exceptions to this rule (like Bryan said), but I would let him try to find an exception that allows it.

Steve

 

[paul]

Re: Control panels used as raceways

Originally posted by steve66:
I would reject this based on 300.3(C) unless he can show that the low voltage cable is rated for 480 volts. There may be some exceptions to this rule (like Bryan said), but I would let him try to find an exception that allows it.

Steve

Steve,

The FPN on that article tells us to look at 725.55(A), which tells us we can share the same enclosure with Class 2 and 3 circuits as long as we follow the rules of separation.

My opinion is it's legal, but cheesy.

[ March 17, 2005, 11:33 PM: Message edited by: paul ]

 

[steve66]

Re: Control panels used as raceways

My basic take on this is it is crappy workmanship - even more so if it is a network or data cable. If Glenn is the owner or engineer on the project, I can see why he would want this corrected.

To show this complies with the NEC, the AC contractor would first have to prove that he has a class 2 or class 3 circuit. Then he would have to provide the "barrier" Paul mentioned.

In addition, I would want him to show there aren't any manufacturer instructions suggesting to stay clear of line voltage/ high current wiring.

Finally, if this were an existing enclosure, I might be tempted to mention something about it being private property, not part of his contract, not his to mess with, and kindly seal those holes you put in my panel after you get your stuff out of it.

Steve