Panel Vent and Fan Location Advice Please


I have two panels about ready to ship. I calculated the thermo load when sizing the enclosure but I am worried they are both still getting a bit warmer then I like.

One has a PLC, touch panel and such in it ... the other has 12 contactors in it.

One panel measures 36 x 36 x 8 (contactor panel) ... the other 36w x 48H x 12D.

These are going inside a protected climate controlled building.

So, I found a fan (120 mm ... quite with good air flow) ... and a louvered 3R grill (about twice the size of the fan opening).

Now, where to put them ...

I am thinking the fan should blow in and be low ... with the vent high?

I could also put the vent low and suck the air out high.


I have always avoided putting in a fan, but I had the contactors on all day and they are measuring 130 deg surface temp on their coils (hottest spot ... low temp near the top of only 80 deg). This is with the door of the enclosure open and no load on them (not that it will generate any heat).

Any advice would be greatly appreciated.

At a minimum use a simple filter on the inlet to minimize debris build up.

The temps don't seem particularly high for the contactors. Your more sensitive electronics will be better off with air circulation.
Thanks! I was thinking of a small computer style filter (really a fine mesh head on by magnets so easily removed and cleaned).

In 30 years, I have never used a fan .... this is the largest panel I have ever built and one of the few with a PLC. I always overbuild my panels. If they need a 5 hp contactor, I put in a 7 1/5, so this is really a "safe then sorry" item.

Thanks ... Mike
I have executed many panels and in such scenario I keep louvers (filters) in the bottom and Fan at the top so that cold air intake from bottom) and hot air exhaust (from top of panel) will happen, and an interlock fan with a temperature switch to power on only when it reaches the temperature set point.