MCC- Safety Concern
- Thread starter C_A
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zog
Senior Member
- Location
- Charlotte, NC
tryinghard
Senior Member
- Location
- California
Shouldn't be anything in there too hot right. 
I wouldn't want to spray if contacts randomly open or close though.
I wouldn't want to spray if contacts randomly open or close though.
zog
Senior Member
- Location
- Charlotte, NC
Nfpa 70e 130.6(h)
Spray painting and glossiness affects surface emissivity which affects heat transfer from the enclosure. It may or may not be a problem. You could test for internal heat rise before and after but I don't know what standard to use to gauge the effect of your measurements.
weressl
Esteemed Member
Not only live but even de-energized spray painting is not a good idea.
- Unless it is water based paint you would be creating a potentially explosive atmosphere and the MCC would be a source of iginition.
- The spray paint would coat the contact surfaces, eventually causing them to prematurely pit and fail.
- The spray paint would undubtedly get into the iron core surfaces of the contactor solenoid, eventually causing them to burn up the coil.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
I used to work for an MCC manufacturer and every now and again, we would get a Consulting Engineer on a project who INSISTED on an MCC being a specific color. They seemed to think it was OK to just paint them after the fact. It wasn't. As I recall (it's been over 25 years now), there was something in NEMA ICS or UL845 about not re-painting an MCC with any conductive material inside, so if you wanted a different color it had to be done pre-assembly.
One project shipped out and although we had taken exception to the color change, the contractor hadn't noted it in the bid and nobody caught it until it showed up on site, where the CE rejected it for being the wrong color (he wanted baby blue, it was hideous). So we had to strip out ALL of the units, panelboards, main and vertical bus bar etc.. We had it electrosatically painted in the field, which significantly cuts down the mess, but even using that process I witnessed exactly what weressl mentioned, the paint spray got EVERYWHERE inside that MCC and had there been any bus bars or units installed, it would have been all over everything.
I also had several end users paint MCCs after the fact, then complained about component failure afterward. The only one I have seen that didn't was painted with a roller and brushes, but that was just plain horrible looking. Even then I don't think ANY of them were foolish enough to have done it live.
Doing it live is a suicide wish. VOC based paint is a fire waiting to happen, water based paint is a flashover waiting to happen. Either way, I would not want anyone I know or like holding that spray gun!
One project shipped out and although we had taken exception to the color change, the contractor hadn't noted it in the bid and nobody caught it until it showed up on site, where the CE rejected it for being the wrong color (he wanted baby blue, it was hideous). So we had to strip out ALL of the units, panelboards, main and vertical bus bar etc.. We had it electrosatically painted in the field, which significantly cuts down the mess, but even using that process I witnessed exactly what weressl mentioned, the paint spray got EVERYWHERE inside that MCC and had there been any bus bars or units installed, it would have been all over everything.
I also had several end users paint MCCs after the fact, then complained about component failure afterward. The only one I have seen that didn't was painted with a roller and brushes, but that was just plain horrible looking. Even then I don't think ANY of them were foolish enough to have done it live.
Doing it live is a suicide wish. VOC based paint is a fire waiting to happen, water based paint is a flashover waiting to happen. Either way, I would not want anyone I know or like holding that spray gun!
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
I wonder if you could hook up a temporary pressurization line to the MCC while the painting is going on to keep paint out of the inside of the MCC.
It does not sound like a good idea in any case from what some are saying from bad experiences.
It kind of bothers me because it is not an unusual thing to do in the field. I can't tell you how many MCCs and other electrical equipment I have seen repainted this way in the field.
I have not noticed paint on the insides of them. Maybe I did not look close enough.
It does not sound like a good idea in any case from what some are saying from bad experiences.
It kind of bothers me because it is not an unusual thing to do in the field. I can't tell you how many MCCs and other electrical equipment I have seen repainted this way in the field.
I have not noticed paint on the insides of them. Maybe I did not look close enough.
weressl
Esteemed Member
This(OP) is the type 'question' that drives me up on the wall, down and back up again!:grin:
I deal better with issues when the objective is stated. We are all educated, trained and hired as problem sovers and solution providers.
In this case, if the objective is purely esthetics, then remove the doors and sidepanels, remove the attached hardware from it, prep it and paint it with hatever painting method you chose - spray, poweder, electrostatic, combinations of those - in appropriate coating facilities.
If the objective is restorative, then one would need to further investigate what else is deteriorated. If there is visible then it is likely that internal components suffered some damage and the overall job assesment may dictate to aim toward replacement.
...and so on and so forthings.:roll:
renosteinke
Senior Member
- Location
- NE Arkansas
NEC prohibits 'foreign contaminants' from the insides of panels and such. This is a favorite of the HI crowd, who zero in on even the slightest sign of overspray or spatter.
A nice, deliberately applied paint job on the inside? Well, some would welcome that as an invitation to debate just what 'contamination' means. (Personally, I believe they are misapplying the section, which I believe is concerned about the integrity of connections and insulators).
Outside? I have no problem. Nor have I any problem with painting an unmounted cover or dead front. Not with any sort of paint- even a 'metallic.' Dang things ARE metal, after all.
Article 110 does tell us to protect metal against corrosion. Untill fairly recently, there was no requirement that the metal be galvanized before painting; as a result, there are many enclosures out there that need regular maintenance.
A nice, deliberately applied paint job on the inside? Well, some would welcome that as an invitation to debate just what 'contamination' means. (Personally, I believe they are misapplying the section, which I believe is concerned about the integrity of connections and insulators).
Outside? I have no problem. Nor have I any problem with painting an unmounted cover or dead front. Not with any sort of paint- even a 'metallic.' Dang things ARE metal, after all.
Article 110 does tell us to protect metal against corrosion. Untill fairly recently, there was no requirement that the metal be galvanized before painting; as a result, there are many enclosures out there that need regular maintenance.
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