# Component Spacing Inside Control Panels



## JRaef (Mar 23, 2009)

TransistorGeek said:


> Hello Everyone! I'm just wondering if there is a specific requirement for air gap spacing between electrical parts in a control box? Do we need to perform software simulations or thermodynamic heat transfer calculations everytime or is there a simple, IEEE or NEC approved standardized set of rules for making these determinations? Thanks!


The rule is, whatever the manufacturer of the component says it is. In other words, you must follow all mfr instructions when installing components, and if the mfr says they can be stacked next to one another with no air gap, then that's acceptable. For example, with AB component class drives, the PF4 series must have a 1" gap side to side if you want the enclosure temperature to be 50C max, but if you can limit it to 40C, then they can be directly touching each other.

I have also seen that people assume, incorrectly, that IEC motor starters, which typically have no spacing gaps mentioned, can be jammed into an enclosed space with no thought to heat. But if you CAREFULLY read the instructions, they will tell you that bi-metal thermal OLs put out about 3W of heat per running load amp. So stacking 20 x 75HP IEC starters in a box chunks out almost 6kW of heat! Then everyone gets excited about the ones in the middle of the stack over heating...

In other words there is no excuse for not using common sense.


----------



## Jlarson (Jun 28, 2009)

JRaef said:


> I have also seen that people assume, incorrectly, that IEC motor starters, which typically have no spacing gaps mentioned, can be jammed into an enclosed space with no thought to heat.


I love when people build their own "mcc"  out of a multi door can and just pack it solid with IEC starters from one end to the other and of course they all have front aux contacts with all the aux wiring dressed tight over the top of the whole f'ing row . The bad one is always the one right in the middle too


----------



## JRaef (Mar 23, 2009)

Jlarson said:


> ... The bad one is always the one right in the middle too


Murphy Rules!
:hang:


----------



## Jlarson (Jun 28, 2009)

It's like surface of Venus hot in that F'er too. Top row of combos it too hot to touch :laughing:


----------



## Aydin2011 (Apr 2, 2013)

Jlarson said:


> It's like surface of Venus hot in that F'er too. Top row of combos it too hot to touch :laughing:


At least yours is good looking. Here is the worst one. When u take look at vfd power 480 vac 3 phase sharing like residential receptacle no protection, no space it is bothering me . But not my boss)


----------

