ECN Forum Forums General Topics of the Trade General Discussion Area Walk in cooler

It's a design issue.

As others have pointed out, the heat tapes are used primarily on freezers. What's left unsaid is that the freezer is often accessed from within the cooler itself. This would put the receptacle in the cooler- though out of the freezer.

Even if the receptacle can be placed completely outside the sooler, it's still something the electrician has to power up.

schenimann ;

The Information submitted so far by the other Members should be what you need.

I would like to add a few things to the list of data:

If the Cold Box is a "Freezer" - having a Target Nominal Design Temperature of 32ºF (0ºC) and lower, figure these following Design Specifications:

1. Use XHHW type Insulation inside the Cold Box, for the Conductors,
2. For any Low Voltage Cables (Temp. Sensors, Relative humidity Sensors, Freon Sensors), the Cable Jacket + Conductors should be suitable for Ambient Temps below 40ºF. Something equal to "FREP",
3. If you use Fluorescent Strip Fixtures, GVA makes a nice sealed, gasketed surface mounted unit, designed for low temperature installations.
   For best performance, use 4' T5HO (F54T5HO) and Programmed-Start Ballasts,
4. The Man Doors _SHOULD_ include Door Heat (Heat Trace Cable), which is pre-installed by the Manufacturer.
   Typically, Man Door Heaters are 400 VA @ 120VAC, and use Self regulating Heat Trace.
   This would be common Specs for a typical 3'-6" to 4'-0" Man Door.
   Heat Trace terminations will be made on the "Ambient" side of the Door, on the upper corner of the Door Trim, opposite side of the Door's Latching (Hinged Side).
   Typical connections are terminated in a Single Gang Bellbox,
5. To Seal Off the Penetrations, fill at least 12" of whatever Conduit is entering the Box with dense foam sealant.
   Seal the Penetration through the Insulated Panels as well.
   (I have Seal-Off detail Drawings; let me know if you would like a copy for reference),
6. I typically Specify NEMA 4X Enclosures in Coolers and Freezers, but NEMA 3R will work as well,
7. The Evaporator(s) will require at least One Disconnect Switch mounted on or near the Evaporator Unit.
   These may be Non-Fusible EXOs.
   Need One Disconnect for the Evap. Fans, and One for any Electric Defrost Heater Arrays.
   Use NEMA 3R or 4/4X Rated Enclosures,
8. Drop into each Disconnect with Sealtite (LFMC).
   We drop into the Cold Box at each Disconnect location, from a Seal-Off / Jbox Assembly mounted on the Ambient side of the Lid (Ceiling),
9. For Defrost Terminations & Fan Delays, drop into the Evaporators as is done for the Fan / Defrost Heaters whips,
10. If the Liquid Solenoids are external, these will be mounted above the Hard Lid. Connect a pair of #14s per LSV, and run back to the C.U.
11. Drain Line Heaters: These are typically wrapped with 6 VA per Foot Heat Trace Cable, using a Ratio between 1.41 and 3 Wraps per Linear Foot.
    Typical Drain Line allotments would be 600VA per Evaporator, unless tighter wrap ratios are requested,
12. Place the Lighting Switches outside of the Cold Box - at the Man Doors, unless Project Specifications require the Switches to be inside the Box.

Mostly the same will apply for Coolers. Drain Line Heat and Door Heat will likely not be used in Coolers; Defrost might likely be Air Defrost (no Electric Heaters or Hot Gas Defrost).

Conductor Insulation may be THHN if Design Temperature is >+36ºF

As for the Condensing Unit(s), the Evaporators will likely be driven from the C.U., so this is where you will pick up the Branch Circuitry for Evaporator Fans and Defrost Heaters.

Freon, Humidity and Temperature Sensors, along with the Defrost Terminations / Fan Delays, will Terminate to Control T-Blocks at the C.U. - unless separate Control Panels / Equipment is used with the Sensor Systems.
A typical example would be Temperature Sensors controlling LSVs via a Johnson A419 Controller.

There are a few other things to mention, but I will stop here.

*** IMPORTANT NOTE ***

Verify all Installation Data against the Project's Specifications - Electrical Plans, Cutsheets, Vendor Specific notes, Ref. Contractor's Specifications, Manufacturer's Data and Specifications, as well as the Project Manual.
Verify installation notes per each "Section" of the Plan Set - i.e.: "A" Sheets, "R" Sheets, "M" Sheets, "P" Sheets, "S" Sheets, as well as the Cutsheets from the Cold Box Manufacturer.

Best bet is to consult with the Refrigeration Contractor for specific stuff.

Try obtaining as much relevant information possible. If the specific details &/or Requirements are unclear, or you are unsure of what to do, feel free to post a reply.

Good Luck.

-- Scott

After looking over the plans this is what they have. There is a "processing room" with a meat saw, grinder etc. This room has a fan and a condensor. This room leads into a "Walk in cooler" with a fan and a condensor. Other that breaker sizes and lighting specs, this is the info they have provided me with. I am certaintly not a veteran commercial electrician, but with the information that you guys have been so helpful with, I would say I don't have enough to give an accurate quote. Would you concure with my hypothesis?

Actually, you do have enough information. I can't tell you what the rules are in the US, but our code books aren't that different, so I expect you have the rules at your fingertips. It isn't a freezer and you can expect food handling to include wash-down. In Canada, I would wire it as a Category 1 location. Can someone translate that to American?

A couple of posts mention using spray foam inside raceways, is that stuff approved for use within electrical equipment?

That kinda a thin line to walk on that IMO they genrally not approved unless the UL did test on them however I know the UL did test on flamé test on them but for other means I am not too sure on UL side but in France we can do that but it will not honour the warranty if the expanding foam cause issue with it { what I heard some can attack the plastique materals }

Merci.
Marc

Noté: I think John { Reno } may know little more on this matter so if he do read this so he may comment little more on his part.

Good heavens ... a little secret here ... the linesmans pliers and wire strippers you use are NOT UL listed.

The presence of a UL lable on the can could even be misleading. There's no UL standard for conduit sealing compounds, so any UL listing would relate to its' use as a fire stop, flame spread, or some other use not related to this thread.

Code just says you need to seal the conduit - and is silent as to how. There's no listing requirement, or even an 'approved method' required. You could use old bubble-gum and still be legal.

Still, we are expected by Article 110 to protect the wires from damaging chenicals, etc. So, maybe it's not so crazy to ask 'will this stuff hurt my wires?'

To answer that, we can look to the NEMA studies that explored expanding foams and non-metacallic cable (Romex). Tere were no issues found; foam and the PVC jacket of the cable got along just fine. Since the in sulating part of THHN is also a PVC compound, it's safe to say the foam won't hurt anything.

Please note that we're still expected to arrange the conduit to drain, etc. This might even mean doing things like installing drain holes, and other actions not considered by UL when they rated the various components.

We must have a different type of romex BC safety authority bulliten can be found HERE

Doug:
I don't think it's a different type of romex (NM cable) but different types of spray foam!

The polyurethane type you linked to and NM cable have issues, however the latex based spray foam is not an issue with NM. IMHO, Reno is referring to the latex based product.

I have not come accross any 'foam' being used for sealing conduits btwn different temperature areas. The polyurethane based foam may not have any effects on THHN/THWN/MTW as it is gasoline/oil resistant. Duct seal is the product of choice.

http://www.nema.org/...ed%20in%20spray-foam%20insulation.pdf

Document is from 1985 and, oddly enough, the research was performed in Canada. At that time the ONLY spray foam available was the polyurethane type.

IMO, the latex stuff is junk anyway.