Running conduit into main feed of machine

I once heard there was a rule for running conduit containing 480V into the side of a machine at a horizontal angle. If it comes straight down from the ceiling to the machine, it could cause a arc from condensation build up.

Is there any truth to this?

If so, do you know where in the rules it is?



Thanks in advance!

I don't think there is such a rule. May be some particular company rule.
If you pose your question here you will get the most knowledgeable electrical answer in the world.

http://forums.mikeholt.com/

kinda like this site is for PLC's

If there is enough moisture in your atmosphere for you to experience condensation build up in your conduit, then said conduit is not fit for purpose and your mains cables should be IP rated for the job. Enclosed cable and glands from source to cabinet.

You will get condensation if there is a temperature difference between the ends of the conduit. E.g. if you're running the conduit from a roofspace into an air conditioned food processing hall, then you WILL get condensation. This applies whether the conduit is vertical, horizontal, or put in by crazy-eye johnston on a 27 degree angle.

This doesn't just apply to your mains, either. Obviously the SAFETY risk is higher with higher voltage, but the functionality/equipment risk is the same with any type of cable.

In this situation I always specify the board to be bottom entry, run the conduit down level with the bottom of the panel and then loop the cables into the bottom of the board through a gland. Then stand back and watch all the condensation dripping harmlessly out the bottom of the open conduits, and be thankful it's not dripping into your main isolator or your PLC

Ditto to ASFs comments. You can also use silicon (silastic) food rated and seal BOTH ends of the conduit. To prevent air flow from both temperatures.
I prefer ASF method though.