3 Ph single conductors

I can't speak to their thinkiong, but I do know that water (leaks, condensation, etc) can "hang" between runs that are too close - corroding, embrittling from contaminants, and lowering resistance value of insulation. It can also allow "wicking" (capillary action) which can draw water into boxes, supports, etc.

Are you speaking of overhead, in conduit or in cable trays and or ducts?

in article OYg3d.59957$KU5.38517@edtnps89, Dave at snipped-for-privacy@telus.net wrote on

I do not understand what you are asking. I am not an expert on code practices. First you say single conductor and then you say A,B,C as if there are three conductors.

Aside from any code considerations, running single conductors through metal conduit does is not wise. The conduit will act as a shorted turn secondary against the single conductor.

Bill

on

They are 500 mcm single conductor tech cable runs of a 3 ph 480 volt feed to a MCC section. They are run up in a wooden ceiling strapped to 2x4's. I believe the spacing is to reduce sheath currents due to the magnetic field cutting through the aluminum armor.

Dave

Are the really saying you can't use the "single conductor in free air" ampacity

| It can also allow "wicking" (capillary action) which can draw water into | boxes, supports, etc.

That can be stopped with a separator to fan the wires apart at each end.

Section 330 10(A)(13) allows single conductor type MC cables to be grouped together.

The one diameter spacing I believe comes from section 392 11 which applys to cables in tray.

wrote

From what I am reading/understanding, you need the help of a pro that is local to you. Strapping 500 MCM to an wood surface is an violation of everything good and true that I know. Please call some one for an estimate locally.