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MC in a walk-in cooler

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Is there any issue with using MC (standard, not jacketed) on the interior of a walk-in cooler ??
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Elect117

Senior Member
Location
California
Occupation
Engineer E.E. P.E.
300.6(D) - 1/4" off the wall of areas where they are going to wash.

300.7 - where it might enter or exit the walk in cooler it requires sealing adequate to prevent condensation or the transfer of heat into the colder environment. You would also need to compensate for thermal expansion/contraction when the cooler is being serviced or cleaned (when not running).

I think it would be a poor design choice for most circumstances but I can't find a reason it would be against code (granted the MC is a type suitable for wet/corrosive environments).
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
The inside of a walk in is one of the dryest places you'll find. You could make jerky in there.
Right, the concern is where the metallic sheath emerges from the thermal insulation into the warm, comparably moist surroundings. The sheath could be colder than ambient due to thermal conduction from the cold side of the insulation.

Cheers, Wayne
 

Elect117

Senior Member
Location
California
Occupation
Engineer E.E. P.E.
The inside of a walk in is one of the dryest places you'll find. You could make jerky in there.
Right, the concern is where the metallic sheath emerges from the thermal insulation into the warm, comparably moist surroundings. The sheath could be colder than ambient due to thermal conduction from the cold side of the insulation.

Cheers, Wayne

Everyone I have been in is wet. When i used to work in the restaurant they would just hose it down. And every food cold storage facility does the same thing. Most freezers have ice forming on doors seldomly used.

Maybe I am thinking food cold storage and you guys are thinking the beer coolers at gas stations?
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Where we penetrated the unit we would use a short piece of EMT between a box inside the unit and a box outside on top sealed with duct seal.
 

rambojoe

Senior Member
Location
phoenix az
Occupation
Wireman
Everyone I have been in is wet. When i used to work in the restaurant they would just hose it down. And every food cold storage facility does the same thing. Most freezers have ice forming on doors seldomly used.
This is my experience as well...
For me, its always spec'd out in pipe, wp fittings and vapor proof/bells.
Dont forget the caustic degreaser..
 

rambojoe

Senior Member
Location
phoenix az
Occupation
Wireman
Never seen pvc either...
Most of the big ones (re-BIG) come pre fabbed but either the order gets screwed up or the pipe is too small in the wall.
Its mostly run outside the panels and sealed.
 

mtnelect

HVAC & Electrical Contractor
Location
Southern California
Occupation
Contractor, C10 & C20 - Semi Retired
We do maintenance on produce warehouses, with the principle of "Thermodynamics" before any temperature drop the latent heat has to be removed first. Inside it is a very dry climate.
 
The inside of a walk in is one of the dryest places you'll find. You could make jerky in there.
Strange how so many many think a walk in cooler or freezer is wet or damp. I have never seen it Where does this come from? Maybe cuz stuff is cold it sort of registers as damp in the 🧠? Maybe cuz stuff often sweats after coming out, and no one noticed is was dry before it came out? . Never got a damp hand grabbing something from my fridge or freezer. Used to work at a restaurant in my teens and was the one called upon to run to the walk ins for stuff. All sorts of stuff in cardboard boxes there .
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
Everyone I have been in is wet. When i used to work in the restaurant they would just hose it down. And every food cold storage facility does the same thing. Most freezers have ice forming on doors seldomly used.

Maybe I am thinking food cold storage and you guys are thinking the beer coolers at gas stations?
The inside of the dry pantry would be wet if they hosed it down. Nobody is hosing down any of the ones that I've been in. What do you do with all the food that's not in sealed containers?
 

mtnelect

HVAC & Electrical Contractor
Location
Southern California
Occupation
Contractor, C10 & C20 - Semi Retired
In the produce warehouses we work in, 18 wheelers are coming and going, forklift drivers are taking the boxed produce into the warehouse coolers. It's a very busy environment. They have curtains blocking air movement on the docks and at the entrance of each cooler. Then they have sorting tables to re-box to the stores. They throw away a lot of product ! They have several winter coats hanging outside each cooler.
 
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