The walk in coolers I have done in the past have been wired in mettallic sealtight, the last one the cooler contractor stubbed the wiring for the door's straight up on to the top of the cooler in sealtight than we took it from there. My current job I am responsible for all wiring and the door wiring came with a piece of alum. flex hanging off the wires, is this okay to stub thru the ceiling of the cooler and run a few feet to a box or would you change it. The wiring penetrations have to be sealed inside and out just doesn't seem right with alum. flex.
Question on cooler wiring
- Thread starter KWH
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iMuse97
Senior Member
- Location
- Chicagoland
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
You could terminate the FMC in a box on the ceiling and then leave the cooler with some other raceway - sealing it right where it leaves the cooler. Just an option. One install it may make sense the next install changing to LT flex may make more sense. It doesn't need to be watertight, unless it is a washdown area.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
I'd switch to LFMC. Condensation will ruin the FMC, IMO.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
If flex is vertical or mostly vertical as appears to be the case condensation will not accumulate in the flex, it will drain into the cooler door wiring compartment. This will be the case no matter what kind of raceway is used. By nature of FMC construction some water could leak out of raceway before reaching the end, but otherwise it will have a tendency follow pull of gravity. Sealing the raceway from conditioned to non conditioned air is what reduces condensation.
iMuse97
Senior Member
- Location
- Chicagoland
Yes, that's it. Now I remember how I did these: I ran the sealtite to a JB (4x4 or 11B) mounted on the exterior of the cooler exactly where the sealtite exits the cooler. So the sealtite is coming into the back of the JB which itself is mounted to the surface of the cooler. Sealed around the fitting with appropriate silicone RTV and sealed the interior of the LFMC with ductseal.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
It would also be a good idea to make sure the cooler never goes into defrost, that would help.
I'd stick with the LFMC.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I still don't think it matters much. It is either going to condense in the raceway or it is not. Type of raceway will not make much difference.
The idea of defrost is to not raise the temperature of the entire refrigerated area but to apply enough heat to the evaporator coil to remove any ice build up on the coil. Once the coil is cleared of ice the purpose of defrost is completed. They usually have thermostats installed on the coil to terminate defrost once a certain temperature is reached. Many times they turn off lights (maybe not so much anymore, especially with LED lights) and door frame heaters during defrost cycle to reduce the amount of heat gained in the refrigerated space during the cycle. During a defrost cycle you are not bringing in warm humid air that can condense you are adding heat to what is already there. Newer systems use hot gas through the coil instead of electric elements and are much more effficient when it comes to how much heat is introduced into the refrigerated space during a defrost cycle.
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