Panel in a damp location

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Bill Annett

Bill Annett

Senior Member
Location
Wheeling, WV
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Retired ( 2020 ) City Electrical inspector
Hi, I have a person who wants to install an electrical panel in a damp location, their basement. The existing panel has a lot of corrosion and I recommended that they move the panel to the first floor. They do not want to move it so I have been looking at code article 312.2 (Damp and Wet locations) and the NEMA type of panels that are made for Damp Locations. I wanted to see what I can find to back me up.

In my mind the dampness is a corrosive agent which would require a Nema 4X or 6P.

Am I wrong in thinking that Moisture is a corrosive agent. I am getting the phrase ?corrosive agent from table 110.28. Please let me know what you think.

Thanks, Bill
 
@Bill

I am not sure I would consider the basement a wet or damp location. However, thats your call or better yet the local AHJ's call based on local experience since their is a informational reference (not enforceable) under the definition of damp location.. I would tend to say the corrosion being experienced is probably due to it being installed on a cinder block or concrete wall and so on but thats me assuming again.

Regardless, you can always install a Enclosure Type 3R inside if you wish but honestly I do not consider what you are talking about as "corrosive agents" and I certainly don't think Table 110.28 would either.

If that was the theory of "corrosive agent" then you would see a 3R listed for that and it is not...yet it is exposed to rain, snow and sleet. If you read the last statement of section 110.28 it says " The enclosure is not intended to protect against conditions such as condensation, icing, corrosion, or contamination that may occur within the enclosure or enter via conduit or unsealed openings"

If this is the case then look at 312.2 for some guidance as well. The panel enclosure being in a DAMP location (if thats selected) then I would install a Type 3R, maintain the 1/4" air space on the surface mount and end it there.

Hope this is helpful.
 
iwire said:
If panels in basements are a problem than about 99% of New England's homes are in violation.
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They all could move to Arkansas as they tend to not have basements...;) Anyway thats the problem with an Informational Note under "damp" locations, it tends to create a "catch all" mentality, kinda like "such as clothes closets" does.
 
Location, Damp. Locations protected from weather and
not subject to saturation with water or other liquids but
subject to moderate degrees of moisture. Examples of such
locations include partially protected locations under canopies,
marquees, roofed open porches, and like locations,
and interior locations subject to moderate degrees of moisture,
such as some basements, some barns, and some coldstorage
warehouses.
 
jxofaltrds said:
Location, Damp. Locations protected from weather and
not subject to saturation with water or other liquids but
subject to moderate degrees of moisture. Examples of such
locations include partially protected locations under canopies,
marquees, roofed open porches, and like locations,
and interior locations subject to moderate degrees of moisture,
such as some basements, some barns, and some coldstorage
warehouses.
Click to expand...

As stated in my previous post, that is part of the information note in the 2014 NEC, it was part of the definition in the 2011 NEC. Big difference in how individuals take it and apply it.
 
The great state of NC using an association to NCSU studied housing designs in respects to basements
and raised foundations.

What their study showed is that building foundation vents were not a asset but a hindrance to a houses
over-all comfort level. They detracted from the proper heating above and the mixing of air could with
various conditions cause other problem.

You can pass the information along that if fact it's better to seal up the basement and close the vents.
Once done they can use a dehumidifier and it will take the moisture out of the basement and the wood
above the walls and even the floor of the basement.

If in fact the foundation or basement walls are that wet and causing mortar to sweat, or real algae to grow
they have problems way beyond a panel change.
 
You may find if you have equipment mounted directly to a masonry wall that is damp/frequently damp you will experience more corrosion even if using a 3R enclosure.

Mounting equipment on a surface that normally remains dry will make a difference.
 
Bill Annett said:
The existing panel has a lot of corrosion and I recommended that they move the panel to the first floor. Please let me know what you think.

Thanks, Bill
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It has been my experience looking at a lot of water damage panels over the years in need of replacing, the seal at the top of the meter is the cause. After water finds its way past the seal it drips to the service entrance cable and then as we describe it in this region wicks it?s way into the service equipment in the basement.

In other words once the inside of the sheath gets wet it is surprising for some how much damage the water dripping will do to the panel
 
Good Morning.



The existing panel is in a business. I guess that if it is not relocated, they will just be replacing it down the road. By that time I do not think I will be around

I want to thank ever one who replied. We are on the 2011 NEC. I will take this information to the Building Official and see what he wants to do.


Thanks Again, Bill
 
Bill Annett said:
Good Morning.



The existing panel is in a business. I guess that if it is not relocated, they will just be replacing it down the road. By that time I do not think I will be around

I want to thank ever one who replied. We are on the 2011 NEC. I will take this information to the Building Official and see what he wants to do.


Thanks Again, Bill
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If it is mounted on a wall that is always/often damp just spacing it from the wall somehow will make a big difference.
 
kwired said:
If it is mounted on a wall that is always/often damp just spacing it from the wall somehow will make a big difference.
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installing it and maintaining the 1/4" will also make a difference. This is all that Sec. 312.2 mandates as well. Again, I would not venture in saying this is a wet or damp location but every location is different.

Personally I would mount it on a piece of treated plywood and install a Type 1 enclosure and move on.
 
Use a stainless steel NEMA 6P or go home


Type 6P Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (hose directed water and the entry of water during prolonged submersion at a limited depth); that provides an additional level of protection against corrosion and that will be undamaged by the external formation of ice on the enclosure.
Click to expand...
 
MasterTheNEC said:
installing it and maintaining the 1/4" will also make a difference. This is all that Sec. 312.2 mandates as well. Again, I would not venture in saying this is a wet or damp location but every location is different.

Personally I would mount it on a piece of treated plywood and install a Type 1 enclosure and move on.
Click to expand...

Treated plywood is treated to resist rot, but is still absorbent just something to keep in mind.
 
kwired said:
Treated plywood is treated to resist rot, but is still absorbent just something to keep in mind.
Click to expand...
well them my original statements stands...lol...just meet 312.2 and go home.

Or if you have the cash....meet iwires response and still go home.;)
 
Around here a typical method due to the stone foundations was to drop a couple of 2x4s down from a floor joist, mount plywood to that and the panel on the plywood. (Or bead boards if old)

This would provide 6" to 14" of clearance between the stones and the wood.
 
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