# Preferred wiring method for Walk in cooler



## Loose Neutral

MC or EMT The last one I did was EMT.


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## Dennis Alwon

I can't imagine using mc in a cooler- It would look terrible, IMO.


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## user4818

LFNMC-B or commonly referred to as "Carflex" or "non metallic seal tite" would be my choice. The ones I did in a Walgreens store I used EMT on the top of the cooler and dropped down with seal-tite to the refrigeration units.


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## al13nw4r3LC76

Peter D said:


> LFNMC-B or commonly referred to as "Carflex" or "non metallic seal tite" would be my choice. The ones I did in a Walgreens store I used EMT on the top of the cooler and dropped down with seal-tite to the refrigeration units.


Indeed. Last one we did was just like this.


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## Loose Neutral

What about the door heaters? Did you drop down for all those?


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## user4818

Loose Neutral said:


> What about the door heaters? Did you drop down for all those?


IIRC the door heaters had a factory made whip that had to be brought out of the cooler box and fed. Either than or there was a factory installed j-box somewhere that needed a feed. 

But I don't deal with this stuff very often so my opinion doesn't count for much. :no:


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## BBQ

Loose Neutral said:


> What about the door heaters? Did you drop down for all those?


I have typically seen and used EMT down the face of the unit to pick up both the door frame and door heater leads.


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## Loose Neutral

BBQ said:


> I have typically seen and used EMT down the face of the unit to pick up both the door frame and door heater leads.


Did you make penetrations for each frame or just one?


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## nitro71

If I was the inspector I would say that the inside of a cooler is subject to damage and wouldn't want to see MC in there. Those coolers get abused. Racks shoved, shoved out. Washed out. Large objects tossed onto racks by teenagers.


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## MechanicalDVR

Peter D said:


> IIRC the door heaters had a factory made whip that had to be brought out of the cooler box and fed. Either than or there was a factory installed j-box somewhere that needed a feed.
> 
> But I don't deal with this stuff very often so my opinion doesn't count for much. :no:


 
That is pretty much the norm for the door panel section. And I always used Carflex inside as well, most places steam clean or at least wash down the interiors.


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## Big John

I'm surprised that everyone is saying EMT. I sorta figured coolers for high-abuse environments and figured rigid would've been the standard choice. :huh:

-John


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## MechanicalDVR

Big John said:


> I'm surprised that everyone is saying EMT. I sorta figured coolers for high-abuse environments and figured rigid would've been the standard choice. :huh:
> 
> -John


 
EMT on the outside not in the box.


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## nitro71

You can use EMT in areas subject to damage. I feel that properly installed EMT is safe in a walk in cooler.


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## B4T

I just wired one and I used MC with EMT as a sleeve.. it looks much better than plain MC cable and clamps..

I put a 1900 box on the ceiling and dropped MC tails to the controls..


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## partyman97_3

We do a lot of for for a local grocery store chain and inside the box they spec Emt with compression fitting and bell boxes. We usually make one penetration for door heaters, frame heaters and lights and a penetration for each of the coils.


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## captkirk

nitro71 said:


> If I was the inspector I would say that the inside of a cooler is subject to damage and wouldn't want to see MC in there. Those coolers get abused. Racks shoved, shoved out. Washed out. Large objects tossed onto racks by teenagers.


 I agree... I would use emt or seal tight if its out of the danger zone.....


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## al13nw4r3LC76

The door heaters in the one we did we were able to run emt to the top of the cooler from a heater box in the wall to the lid. Set a box on top of the cooler etc etc.


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## user4818

One thing I forgot to mention - don't forget to plug your raceways with duct seal when leaves the cooler. I accomplished this by transitioning from the seal-tite to a 4" square box and plugging the seal-tite connector with duct seal.


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## partyman97_3

Good call Peter D. I usually use expandable foam. I push the straw as far down the conduit as I can and slowly pull it out as I press the button. If not the difference in temperature will cause moisture to drip into the j-box.


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## backstay

partyman97_3 said:


> Good call Peter D. I usually use expandable foam. I push the straw as far down the conduit as I can and slowly pull it out as I press the button. If not the difference in temperature will cause moisture to drip into the j-box.


Is expandable foam legal inside the pipe? Would listing be an issue?


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## al13nw4r3LC76

Peter D said:


> One thing I forgot to mention - don't forget to plug your raceways with duct seal when leaves the cooler. I accomplished this by transitioning from the seal-tite to a 4" square box and plugging the seal-tite connector with duct seal.


I'm curious. My foreman wanted me to do that and I didn't understand why. He was the type to layout and then run off not allowing for questions. Is it code? Something to do with the location?


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## BBQ

al13nw4r3LC76 said:


> I'm curious. My foreman wanted me to do that and I didn't understand why. He was the type to layout and then run off not allowing for questions. Is it code? Something to do with the location?



Anytime you have a raceway that passes from one temperature area to another you should be sealing it. Air flows thru the conduit like it is a an air duct. If it is warm air blowing into a cool conduit the water in the warm air condenses on the inside of the conduit, over time this can fill a conduit with water. 

Many times people do not seal conduits and nothing bad happens but with walk in coolers / freezers if you do not seal the conduits completely at every penetration _you will_ have water problems in the future.

I have seen ceiling mounted vapor proof florescent fixtures filled on the inside with ice because the conduit coming in the back of it was not sealed, countless other switch and outlet boxes filled with ice and water due to unsealed penetrations.


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## partyman97_3

backstay said:


> Is expandable foam legal inside the pipe? Would listing be an issue?


To tell you the truth backstay, not sure, but I have never had an inspector question me. I have seen some guys who prefer just using silicon. 

I have seen more than one light fixture half full of water because the pipe wasn't filled. 

In fact some time back I went to grocery store where the water was so bad in a walk in freezer the light switch was completely covered in a block of ice.


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## user4818

backstay said:


> Is expandable foam legal inside the pipe? Would listing be an issue?


I wouldn't use expanding foam. I'm pretty sure they make a kind of expanding foam to plug raceways, but I doubt the generic stuff for windows and doors is suitable. At any rate, if you need to make a change you have a mess on your hands. You have to rip out the raceway and start over. There is no way you're getting all that foam out of the conduit. :no:


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## Jlarson

Peter D said:


> I wouldn't use expanding foam. I'm pretty sure they make a kind of expanding foam to plug raceways, but I doubt the generic stuff for windows and doors is suitable. At any rate, if you need to make a change you have a mess on your hands. You have to rip out the raceway and start over. There is no way you're getting all that foam out of the conduit. :no:


It's actually pretty easy to clean out. I usually yank the conductors out then take a short piece of steel fish tape and put it in a drill and clean it out.


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## user4818

Jlarson said:


> It's actually pretty easy to clean out. I usually yank the conductors out then take a short piece of steel fish tape and put it in a drill and clean it out.


Hmm. I guess it's not as bad as the foam in place house insulation. _That_ stuff is nasty to remove.


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## MechanicalDVR

Peter D said:


> Hmm. I guess it's not as bad as the foam in place house insulation. _That_ stuff is nasty to remove.


 
One small spray of carb cleaner and the stuff just vanishes like magic.


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## MF Dagger

B4T said:


> I just wired one and I used MC with EMT as a sleeve.. it looks much better than plain MC cable and clamps..
> 
> I put a 1900 box on the ceiling and dropped MC tails to the controls..


Why did you sleeve MC? Why not just run the EMT if you were running it over the MC anyway?


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## user4818

MechanicalDVR said:


> One small spray of carb cleaner and the stuff just vanishes like magic.



Good to know! :thumbsup:


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## MarkyMark

backstay said:


> Is expandable foam legal inside the pipe? Would listing be an issue?


The orange kind looks like it is.
http://building.dow.com/na/en/products/sealants/fireblock.htm
The yellow, probably not. Most big box stores carry both.

I usually run EMT to everything in a walk-in. The exception being, sometimes they call for a vapor-tight fixture in the center of the ceiling (or sometimes the health inspector wants us to add more light in the cooler.) In that case I just pop through into the top of the light with an MC whip, and duct seal on top of the unit.


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## B4T

MF Dagger said:


> Why did you sleeve MC? Why not just run the EMT if you were running it over the MC anyway?


I had to run (3) feet up a wall and then (6) feet along the ceiling to a 1900 box..

Sleeving the MC is the best way to keep it neat looking when running along the ceiling without having "loops" in the cable..

The tin they use barely can hold a screw in place from dropping on the floor.. 

(4) 1/2 EMT straps and the main run is done.. :thumbsup:


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## partyman97_3

B4T said:


> The tin they use barely can hold a screw in place from dropping on the floor..


How true. Usually I just use a sheet metal screw, not self drilling, and drive it with my phillips screwdriver. Just a quick tap with my Kleins and than run the screw in by hand.


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## backstay

partyman97_3 said:


> To tell you the truth backstay, not sure, but I have never had an inspector question me. I have seen some guys who prefer just using silicon.
> 
> I have seen more than one light fixture half full of water because the pipe wasn't filled.
> 
> In fact some time back I went to grocery store where the water was so bad in a walk in freezer the light switch was completely covered in a block of ice.


My concern would be the spray foam deteriorating the wire's insulation. Sealing with it would be more complete than you could get with duct seal. Then again, they spray foam the hell out of my wiring in the walls of most new homes.


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## erics37

backstay said:


> My concern would be the spray foam deteriorating the wire's insulation. Sealing with it would be more complete than you could get with duct seal. Then again, they spray foam the hell out of my wiring in the walls of most new homes.


That spray foam stuff is fine for wire insulation and the like.

Acetone's good for dissolving foam but only before it sets up. After that, you gotta do it the hard way :thumbup:


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## JohnR

al13nw4r3LC76 said:


> I'm curious. My foreman wanted me to do that and I didn't understand why. He was the type to layout and then run off not allowing for questions. Is it code? Something to do with the location?


Yes, it is code. Look at 300.7(A)


NEC2008 said:


> 300.7 Raceways Exposed to Different Temperatures.
> 
> (A) Sealing. Where portions of a cable raceway or sleeve
> are known to be subjected to different temperatures and where
> condensation is known to be a problem, as in cold storage
> areas of buildings or where passing from the interior to the
> exterior of a building, the raceway or sleeve shall be filled
> with an approved material to prevent the circulation of warm
> air to a colder section of the raceway or sleeve. An explosion-
> proof seal shall not be required for this purpose.


I read that to mean anything that will A, not hurt the conductor insulation, and B, stop air ingress and egress through the sealed portion.
fiberglass, could probably be used as well. 

I have used the water based spray foam,(easy cleanup) but if the unit is turned on too quickly, it doesn't have time to cure. And will drip down inside your lights. The normal kind will cure anyway, but will take a lot longer.


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