Outside Mcc

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puckman

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ridgewood, n.j.
I have a concern that mcc used outdoors should have some type of condisation heaters used inside the mcc to prevent moisture build up.
Does anyone feel the same about this ? Does anyone know if this is a manditory design rule listed somewhere ?
Thanks for any replies.
 
puckman said:
I have a concern that mcc used outdoors should have some type of condisation heaters used inside the mcc to prevent moisture build up.
Does anyone feel the same about this ? Does anyone know if this is a manditory design rule listed somewhere ?
Thanks for any replies.
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It's a "JRaef Mandatory Design Rule", but it's not mandatory at far as the National Electric Code, other than the general clause that is often paraphrased as "equipment shall be suitable for the use..." In other words and inspector can, if he so choses, say that space heaters are required to be suitable for outdoor use, and if he says so, it is.

All that said, I don't know of anyone in their right mind that would not do it. Whatever you are putting inside of that MCC will have some wording in the instruction manual that says something to the effect of "keep the equipment clean, dry and free from condensation". That would mean space heaters. If you don't put them in, and something goes wrong that causes the mfr representative to go out there, if he sees that there are no space heaters, you are pretty much going to be left twisting in the wind.
 
puckman said:
I have a concern that mcc used outdoors should have some type of condisation heaters used inside the mcc to prevent moisture build up.
Does anyone feel the same about this ? Does anyone know if this is a manditory design rule listed somewhere ?
Thanks for any replies.
Click to expand...

It is not all that easy to come up with an MCC suitable for putting outside in the first place. One would think the manufacturer would know what it takes to make it work right when you specify that it is outdoors.
 
There are a number of GE 7700 line outside MCCs where I am working at that were installed over 40 years ago and they had heaters in the bottom wireway. The original EC was not careful with the installation of his field conductors in the bottom wireway. A few conductors were damaged from the heat, so the heaters were disconnected over 30 years ago and they have had no more problems with these outside unheated MCCs than with the ones installed in the inside MCC rooms.
 
petersonra said:
It is not all that easy to come up with an MCC suitable for putting outside in the first place. One would think the manufacturer would know what it takes to make it work right when you specify that it is outdoors.
Click to expand...

One would think... But just last week I had an oil company engineer request that I REMOVE the space heaters from the NEMA 3R MCC I'm working on for him. He would not elaborate.
 
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