Senior Electrical and Controls Specialist.

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welcome1

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I have 3 Motor Control Centers that are covered by plastic during rainy periods (3 months). The Roofs of Electric rooms were finally installed but their rusty steel rafters were sand blasted. Is there any advise before I re-certify them by a third party testing company. The onus is on the General Contractor.
 
welcome1 said:
I have 3 Motor Control Centers that are covered by plastic during rainy periods (3 months). The Roofs of Electric rooms were finally installed but their rusty steel rafters were sand blasted. Is there any advise before I re-certify them by a third party testing company. The onus is on the General Contractor.
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If they were covered in plastic why would they need to be re-certified, whatever that may mean to you?
 
Condensation under the plastic?
Conductive sand blasting dust with non dust resistant enclosures?

Depends on how well covered.

Tapatalk!
 
The MCC mfr will have had instructions saying that if they are stored, they must not only be covered, but heated. Without heating, the cold air allows metal surfaces to collect condensation, which can lead to traces of contaminates on conductive elements and increases the risk of flash over. Most likely any warranty (assuming they were new) is void if no heaters were installed.

I would contact the mfr. and see if they will do something for you, but don't hold your breath.
 
Jraef said:
The MCC mfr will have had instructions saying that if they are stored, they must not only be covered, but heated. Without heating, the cold air allows metal surfaces to collect condensation, which can lead to traces of contaminates on conductive elements and increases the risk of flash over. Most likely any warranty (assuming they were new) is void if no heaters were installed.

I would contact the mfr. and see if they will do something for you, but don't hold your breath.
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what difference does it make that they are heated in storage if they are not heated when in use?
 
They will be heated when in use, i.e. I2R, but anti-condensation heaters are a good idea. Regardless, heaters are a must when being stored. The specification should have required them to follow manufacturer instructions for storage. If they didn't then simply reject the equipment. If they did follow instructions, and heaters were not required, then there is no issue.
 
petersonra said:
what difference does it make that they are heated in storage if they are not heated when in use?
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kingpb said:
They will be heated when in use, i.e. I2R, but anti-condensation heaters are a good idea. Regardless, heaters are a must when being stored. The specification should have required them to follow manufacturer instructions for storage. If they didn't then simply reject the equipment. If they did follow instructions, and heaters were not required, then there is no issue.
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Besides that, the OP implied that these were stored where there was no roof and getting rained on, just covered in plastic. The issue of heating is required IF the equipment is not stored in a clean, dry environment. So if that detail was left out of the OPs scenario and the MCCs were covered in plastic but stored at a climate controlled facility, then that's fine.

Why he would mention the rainy season and the fact about the roof finally being put in place would be a mystery though.
 
Depending on the details, I have seen plenty of water damage from condensation in items stored under plastic in the rain.
Particularly if over a wet surface, even when raised on cribbing.

Tapatalk!
 
SECS

SECS

petersonra said:
If they were covered in plastic why would they need to be re-certified, whatever that may mean to you?
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Public Works Deals in Specification! before the owners take possession of the equipment . it must meet certain engineering, manufacturers standards as well as NETA testing. This equipment was NEMA 1 rated as such it does not have any outside protection. The equipment was covered but not sealed.
 
Space heaters are normally recommended as a defense against condensation. I had believed at first that the space heaters were there to warm the enclosures but that is not the case. The space heaters cause the air to circulate because of their heat. The moving air prevents moisture from condensing on the surfaces. When the gear is placed into service it generates its own heat. Often times thermostats are added to turn on the heaters in order to circulate the air when the gear is not energized.
 
If the purpose of the space heater was merely to move the air, it could be done cheaper w/ a simple fan. What the heater does is raise the temperature well above the dew point, which is what keeps the cabinet dry.
 
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