Flexible Metal Conduit-Type FMC inside walk-in cooler evaporator case.

[David Goodman]

I came across a walk-in cooler today with FMC runs inside the evaporator case. Would you agree that this was a violation of 2014 NEC Article 348.12(1) prohibiting use of FMC in wet locations?

Did any prior NEC's allow for use of FMC in wet locations?

 

[iwire]

I came across a walk-in cooler today with FMC runs inside the evaporator case. Would you agree that this was a violation of 2014 NEC Article 348.12(1) prohibiting use of FMC in wet locations?

No I do not.

In my opinion most walk in coolers are not wet locations.

And after doing cooler maintenance for about 15 years I find that using wet location equipment in coolers leads to problems.

 

[David Goodman]

No I do not.

In my opinion most walk in coolers are not wet locations.

And after doing cooler maintenance for about 15 years I find that using wet location equipment in coolers leads to problems.

Thank you. I can understand how liquid tight conduit would hold any condensate that might form in the conduit in low spots causing problems. Looks like I need to examine the definition of wet location a little closer. I might not have a good understanding of that term.

 

[iwire]

Here is a picture I took one night in a supermarket dairy cooler

The dairy cooler had been the open type and for energy savings reason the store was adding glass doors to it.

The doors are UL listed cooler doors made by http://www.anthonyintl.com/en/Index.aspx. Notice that they ship with FMC whips on them. I had to run wet location wiring to them due to customer specifications. Kind of dumb in my opinion.

 

[David Goodman]

I came across a walk-in cooler today with FMC runs inside the evaporator case. Would you agree that this was a violation of 2014 NEC Article 348.12(1) prohibiting use of FMC in wet locations?

Did any prior NEC's allow for use of FMC in wet locations?

In this application the FMC was inside the evaporator case with the fans and evaporator coil. So, it was subject to frosting and dripping of condensate from other parts in the case. The FMC was directly above the condensate drain pan.

 

[sparkyjr]

I'm curious I work on coolers all the time this looks to be a walk in dairy cooler. The condensation always becomes a problem. In Kroger's king soopers and city markets its in the specs to use seal tight yet I come across doors like this all the time. I would consider it a wet location. In freezers especially. Just remember that when you change or go through walls and temperatures are different that you need to use some kind of seal (like duct seal) this will help keep the condensation down. I don't see how this can not be a wet location/damp location or even a wash down area.

 

[ActionDave]

I'm curious I work on coolers all the time this looks to be a walk in dairy cooler. The condensation always becomes a problem. In Kroger's king soopers and city markets its in the specs to use seal tight yet I come across doors like this all the time. I would consider it a wet location. In freezers especially. Just remember that when you change or go through walls and temperatures are different that you need to use some kind of seal (like duct seal) this will help keep the condensation down. I don't see how this can not be a wet location/damp location or even a wash down area.

I work in walk in coolers too. Maybe not as much as you, certainly not as much as iwire, but I agree with him, the inside of coolers is not a wet location. It's very dry in there. The only place there is any evidence of moisture is at the condenser. Everything else is bone dry and close to zero humidity.

 

[David Goodman]

I work in walk in coolers too. Maybe not as much as you, certainly not as much as iwire, but I agree with him, the inside of coolers is not a wet location. It's very dry in there. The only place there is any evidence of moisture is at the condenser. Everything else is bone dry and close to zero humidity.

Do you work in them when the refrigeration system is working properly, or when the system has problems?

They can turn into a wet mess when things go wrong. The humidity levels and condensation on walls and other equipment inside the cooler also depends on how often the cooler is entered, if an "air curtain" is used to reduce unconditioned air from entering when the doors are opened, and other factors.

I'm sure you would correct me if I called something a "bus bar" when that wasn't correct. So, I must say that the condenser is not typically the part of the system that has "condensation" on it. It is the evaporator on which condensation will typically form, and for the system I originally posted about, the FMC was inside the evaporator case that was inside the walk in cooler.

I can certainly understand that this might not be an NEC violation because as I think about it, I believe that the FMC was actually factory installed for the wiring to the evaporator fans. Since it was a UL listed system component, then I guess the NEC doesn't come into play.

 

[ActionDave]

Do you work in them when the refrigeration system is working properly, or when the system has problems?

They can turn into a wet mess when things go wrong. The humidity levels and condensation on walls and other equipment inside the cooler also depends on how often the cooler is entered, if an "air curtain" is used to reduce unconditioned air from entering when the doors are opened, and other factors.

And when roof gets torn off a house in a thunder storm a dry location gets wet, the inside of the house is still a dry location

I'm sure you would correct me if I called something a "bus bar" when that wasn't correct. So, I must say that the condenser is not typically the part of the system that has "condensation" on it. It is the evaporator on which condensation will typically form, and for the system I originally posted about, the FMC was inside the evaporator case that was inside the walk in cooler.

Fair enough. I paint with a broad brush but I realize that details are important in a technical discussion.

I can certainly understand that this might not be an NEC violation because as I think about it, I believe that the FMC was actually factory installed for the wiring to the evaporator fans. Since it was a UL listed system component, then I guess the NEC doesn't come into play.

One of the problems with using water tight wiring methods in coolers is moisture stays trapped. With more open methods moisture can migrate out before it condenses and becomes measurable levels of water.

 

[David Goodman]

And when roof gets torn off a house in a thunder storm a dry location gets wet, the inside of the house is still a dry location
Fair enough. I paint with a broad brush but I realize that details are important in a technical discussion.
One of the problems with using water tight wiring methods in coolers is moisture stays trapped. With more open methods moisture can migrate out before it condenses and becomes measurable levels of water.

Thank you, I am here to learn.

 

[sparkyjr]

I work in walk in coolers too. Maybe not as much as you, certainly not as much as iwire, but I agree with him, the inside of coolers is not a wet location. It's very dry in there. The only place there is any evidence of moisture is at the condenser. Everything else is bone dry and close to zero humidity.

I wasn't belittling you at all I'm sorry if I came across that way. All I know is I work in these quit a bit. I wouldn't change it because like said before it is UL listed. But servicing and doing remodels water is a big issue. As far as the condenser it is usually on the roof the unit in the cooler is a evaporator. Evaporator so in my mind it is means there is a potential for water or condensation. I'm assuming the lights are also water tight fixtures. There must be a reason that they are designed this way. Hope this helps let me Know if there is anything I can do to help.

 

[GoldDigger]

... Evaporator so in my mind it is means there is a potential for water or condensation....

But the evaporator is evaporating coolant inside the closed system and not putting moisture into the air. Moisture will condense on the outside of the evaporator coil and must be drained off, but that leaves the air nice and dry and unlikely to condense on any other surface inside the cooler.
The problem comes when humid outside air is allowed to come to the temperature of the inside of the cooler via air leaks or door opening.

 

[roger]

Hang some strips of seasoned beef in front of a fan in a walk in cooler for say 24 hrs and you will see how dry of an area it is when you have beef jerky.
In my experience all factory wiring in evaporators are FMC.

Roger

 

[kwired]

I agree with most of the replies that a cooler is not a wet location in general. Sure there is water condensing off the evaporator coils, if you are running something in that immediate area you may want to consider it to be wet. But about all that is normally in that space is defrost heaters, and some systems don't even have that anymore they send hot gas thru the coil to defrost it when needed. The rest of the cooler is at the most a damp location unless it gets frequent hose down.