adccommunitymod (AutomationDirect) asked a question.
Ground Question again
Created Date: November 19,2009
Created By: dieseltwitch
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I asked a question about grounding before but I need a little bit of clarification, I was told that if there are any electronics on the door of an enclosure that the door must be bonded to the enclosure. does this need to be done if there are only low voltage items on the door? Ie a C-More Micro or a DC power C-More Screen?
Created Date: November 19,2009
Created by: uman
If in doubt...bond to ground especially if there AC inside. Safety could be comprised if a detached power wire contacts the door.
Created Date: November 19,2009
Created by: dieseltwitch
I kind of have to know for sure. getting a ground in cleanly on the door requires repainting/coating the enclosure. i will have to grind off the paint, spot weld in a stud and then re-coat the entire thing.
Created Date: November 19,2009
Created by: sii
My understanding is that if there is a ground stud on the door, an EGC is required regardless of the presence of electronics. No stud, no EGC needed unless there is something on/in the door that is over 50 VAC to ground.
The enclosure would have been manufactured to NEMA standards in regard to whether the stud was needed to maintain ground continuity.
Created Date: November 20,2009
Created by: DetroitSound
Not sure about the regular C More, but the C More Micro has a non-metallic housing. In my opinion, attaching it to the cover does not make it any more or less of a hazard than if it was not there. I'm not certain about this, but the C more micro may qualify as intrinsically safe as well.
I fully understand the concept of bonding, and for certain, if you have pilot devices, switches, etc on the cover of a metallic enclosure, bonding is prudent. Most of the control panels I 've built over the last 10 years or so have been FRP or polycarbonate plastic and use plastic devices. When someone shows me an effective way to bond plastic parts to ground, I'll do it. In the meantime, in most cases I'll ignore plastic items as needing to be bonded.
If anything, if you cut a piece of metal out of an enclosure and replace it with plastic I see it as potentially reducing hazard rather than increasing it.
Created Date: November 19,2009
Created by: dieseltwitch
I asked a question about grounding before but I need a little bit of clarification,
I was told that if there are any electronics on the door of an enclosure that the door must be bonded to the enclosure. does this need to be done if there are only low voltage items on the door? Ie a C-More Micro or a DC power C-More Screen?