Joining stacked electrical power and control panels

[Mike Gattorna]

I have an installation where a separate control panel (36x24x10) is being stacked on top of its related but separate power distribution panel (30x24x10). Bolted together, the unit(s) will be free standing on a housekeeping pad. There will be 8 control wires fed down into the power panel for control of the MCPs. Are there relevant codes (NEC, 508a) that define the mechanical connection of the 2 panels? Is any insulation needed between the joining surfaces? Does the close nipple penetration between the 2 enclosures need sealing? My google searches have been fruitless.

 

[Jraef]

I have an installation where a separate control panel (36x24x10) is being stacked on top of its related but separate power distribution panel (30x24x10). Bolted together, the unit(s) will be free standing on a housekeeping pad. There will be 8 control wires fed down into the power panel for control of the MCPs. Are there relevant codes (NEC, 508a) that define the mechanical connection of the 2 panels? Is any insulation needed between the joining surfaces? Does the close nipple penetration between the 2 enclosures need sealing? My google searches have been fruitless.

If the environment warrants sealing, it warrants sealing. If not, it doesn't matter. You haven't said.

Looked at another way, if the enclosures are Type 12, Type 3 or Type 4 because the environment requires that, then any penetration into or out of either enclosure must meet those same requirements. In that case a "close nipple" alone would not be sufficient, you would need a sealing hub, like a Meyers Hub, on each box, then a close nipple between the hubs.

If the enclosures are Type 1 or are Type 12 only because that worked best, and the environment really only required Type 1, then a simple chase nipple between them to protect the wires would suffice.