I am pricing an install for a new butcher shop. It has a walk in cooler. I have not dealt with these very much. This one will have two doors with 3way switching outside. It calls for 2 strip lights inside as well as a fan.

What is the best way to enter and wire inside of these units? The plans call for seal-offs wherever the conduit enters the cooler. Are these the same seal-offs that are used in explosion proof installs?

There are a few details to pay particular attention to.

First, have a chat with the local health department. Since the cooler will be used for (unpackaged) food, it's likely they will want the piping stood off from the surfaces inside. Maybe Mineralacs will be enough; more likely they will want you to use the plastic stand-offs the HVAC guys use, that hold the pipe more than an inch away from the wall. This space is to facilitate cleaning.

If it's a freezer, you will need receptacles near the doors (inside) to power the heat tape that keeps the doors from freezing shut.

You do NOT need 'explosion proof' seals. Just stuff the conduit with a bit of duct seal or squirt in spray foam.

The cooling unit will need a disconnect switch, and you'll need to run power and t-stat cable from the inside 'evaporator' to the compressor outside. Of course, you'll need to mount a t-stat somewhere. The condenser outside will need a timer -the HVAC guys can tell you which one - to control the defrost cycle.

Just drill through the walls in the usual way; your boxex will close off the holes.

Lights are the usual vapor-tight ones, and Bell boxes work well. Teks screws will mount it all. There's usually a piolt light ot lit switch outside to tell everyone that the light is on.

All I can add is that you mention 'strip' lights, which I take as fluorescent. IF you are supplying the fixtures, make sure the ballast is capable of the ambient temp in the 'box'.

Anything that you install on the interior has to be suitable for 'wash down'. WP in use covers on any outlets & switches. As Reno said....check with the local or county health dept. for any requirements.

Lighted switches, bell boxes, plasic standoffs, vapor tight lights no problem. However I think that the hvac wiring is more complicated than it appears at first. Do you know where I can look at a schematic of one. This would be helpful

On the inside of the cover to the condenser.

I don't have a condenser yet, I am pricing the job.

Some of them can get pretty elaborate with lockout relays, multiple evaporators and such, but the most basic walk-in coolers I have wired normally use a line voltage thermostat inside the box at the evaporator that controls the liquid line solenoid to shut off the compressor on the low pressure control. If it’s a cooler only, it generally won’t need a defrost timer setup, because the evaporator doesn’t get cold enough, but if it’s both a cooler and freezer setup, it will have one. You might also have some door jamb and air pressure vent heaters to connect.
A condensate line heater is normally used in a freezer compartment. I’ve seen them either 120 or 208V, so I would check with the reefer guys on that because it may require add-on GFI/GFP protection.
For the interior wiring, I like to use EMT with pipe hangers, WP compression fittings and LFMC where needed along with WP metal boxes and covers, but I’ve also done coolers with PVC and FS boxes and LFNC where needed that worked out fine. I’ve seen some guys just use LFMC inside the walk-in secured directly on the surface with one-hole straps along regular dry location 4” boxes, so I guess it depends on what the walk-in is used for and your local requirements. I your case, they are storing fresh meat, so I think your state sanitary code is going to come into play.
I just use ordinary duct seal to pack the LB other fittings at penetrations and then run a bead of caulking around the outside of the fittings.
HeatCraft is a big name in walk-in refrigeration sytems. You can download other installation literature from their website, but the one in the link below is pretty typical of what you'll see. The wiring diagrams start on page 40.

HeatCraft

IF you can, walk through and inspect an existing installation.

Many grocery stores permit civilians to enter the back warehouse. You could well talk your local grocer into letting you provide a free circuit inspection.

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To prevent nasty call-backs you absolutely want to cork up the conduit penetrations. Any idea of wiring light fixtures from vertical penetrations directly above should be dismissed. The lenses will gradually fill with water.

( c.f. the jelly jar thread. )

Figure on EMT and Sealtite runs.

Figure on 3/4 minimum for box penetration. Use PVC for such since it's easier to trim and does not break the insulation. Obviously, provide a bonding jumper across it.

Be sure to provide drainage weep holes at low points in your system.

Treat everything as if it was 'outdoors.'

It gets dark inside and on top... General lighting doesn't cut it.

You'll need a long pilot bit to align your penetrations.

Time can be saved by using 45 degree Sealtite elbows -- sometimes. Most Sealtite runs will be 1/2" linking an integral T-stat relay that is set by the HVAC j-man. I've never encountered a T-stat independently mounted.

Figure on dedicated C/Bs since a tripped breaker is lethal.

The low power motors typically found in most chill boxes have internal protection for overloads. Meaning that the disconnecting means does not require fuses. A motor rated double-pole or triple-pole toggle switch gets it done.

Shun LBs, stay with 4-squares; exception: beauty effects.

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I normally penetrate inside the left side of the condenser assembly from the inside out -- avoiding any seam.

Figure on bonding conductors running everywhere; I use solid.

A suitable scaffold will save labor at the condenser.

Topside, use a battery powered spot lamp.

Good luck.

Thanks for the info. Lots of good ideas that I certaintly had not thought of. It's good to have guys who do this stuff everyday. I go to church with the manager of a grocery store. I will check with him about a possible walk through.

I don't want to get too bound up in details, but I do want an idea of time and material for the quote. This helps alot.

One thing that John(Reno) posted above worries me a tad.
Over here, with any freezer/chiller room, with door heaters, you are required to have the heat tape tails come out on the outside of the door.
These usually come out into an enclosure, where they are joined to a permanent supply (ie: is supplied from the refrigeration panel).

Using a recept and a plug in a place that is renowned for moisture is an accident waiting to happen.

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.

I note that the BC link refers to damage that might occur when the cables are moved after the foam has cured. Well, DUH!

I'll bet even a concrete-rated cable (like UF) would be damaged if you tried to pull it out after the concrete has set. Heck, even steel pipe would 'fail' that test!

Why would anyone waste a $6 can of foam on the thumb sized chunk of sealant you need to draft stop that conduit?
I sure would like to watch the installer try to get that out if he needs to do something with those conductors.
Why not use the right thing? Duct seal is about $2.50 a pound and you can get it out later.

Duhhh.....
The spray foam is in a nice aerosol can, and if you're careful...you don't get messy!! The duct seal has to be pulled off of a big block & you have to use your hands!!

What can I say Greg.....convenience at $6 a shot!

Are you kidding? I get several months of use from an 'open' spray can. All it takes is to clean the straw and nozzle with some acetone (carburator cleaner has acetone in it) right after each shot. I particularly like the small $3 cans - about the size of a soda can- you can find from time to time.

Sealing is usually the last thing you do - and you're usually sealing wall penetrations and all manner of other openings at the time. Foam? It's what's at hand.

Spray foam is very difficult to remove from a conduit. Its bad for the next guy if he needs to replace or add wires. If you want other electricians to hate you, put spray foam inside a raceway.

Oh, I won't deny that. Beats the stars out of opening a Chico-filled explosion-proof seal though.

I didn't know that was possible.

I have seen a few instances of a 'sparky' trying to accomplish what Reno is (hopefully) joking about!!

Oh, I've had to do it. Hours of chipping with improvised chisels until the breakthrough.

Naturally, the wires are ruined.

In all of my days...

I've NEVER needed to re-wire the penetration into a chiller.

So you're getting excited over nothing.

If worst came to worst, just abandon the prior conductors and punch another hole; set another j-box next to the prior and carry on.

You're not supposed to cork up anything until the whole unit checks out.

If you're terrified that you've missing something toss in a spare conductor or two. The entire penetration zone is only 6 inches. Scrap conductors that long are all over your spool butts.

------

I've never played Chico & the electrician...

But I understand that warm to hot vinegar does wonders for it.

In which case a suitable nipple full of vinegar screwed into the stopper threads could be heated by electric gun/blower...

And you're making progress.

Tesla:
New to me.....vinegar?? What'cha think Reno??

There are some expanding polyurethane foam type sealant products that are supposedly listed for direct contact with electrical wiring and cable jackets. I haven’t tried it myself, but apparently the Hydra-Seal brand can also be easily removed for future rework.

Hydra-Seal

HotLine ... it almost makes me want to go to the local gas station and try it out!

Now, if only I could find a way to get cured foam out of my clothes ....

Ever the scientist I just tried acetone on some cured spray can foam. (Great Stuff, controlled expansion in the blue can)

It softened it up a little but it did not get gummy or break down in a 5 minute soak. It might help you get it out of your clothes tho but if you have "plastic" clothes it might eat a hole in them.

Trichlorethane 1.1.1 is similar.


Lacquer thinner was even less effective.

This is polyurethane and there is not much that will eat it.

Dynasolve CU-6 says they can do it but this is pretty nasty stuff.

http://www.customlinings.com/industrial/ApplicatorsOnly/MSDS_Sheets/CU6_MSDS_SHEET.pdf

I accidently tried acetone on a nylon windshirt, (Was going to use lacquer thinner on a stain)It did no harm it may have no harmful effect on other plastics....


On the orig. topic, learned the hard way about sealing conduits when came back to fixtures full of water. Lesson learned.

Jay, as far as I'm aware, no, you are supposed to use proper caulking agents inside things like conduits, especially where the conduit could become a fire-path, spray-foam as a rule isn't self-extinguishing, in fact it burns quite readily.
Unfortunately, spray-foam has become the slap-happy approach, leave the spray foam to the DIYers that use it, get the proper stuff.

Scott35,
Is there any chance of you maybe making up a generic wiring schematic for the Tech Reference Area, with respect to basic Refrigeration installs?
At one time I used to be able to do these installs no worries at all, as the EC company I worked for about 10-odd years ago specialised in them, it's a funny thing, when you leave doing that sort of work, it's hard to remember just how it's all done.
If you need a hand doing this, flick me a PM, I can sort of remember what goes into a Reefer install.

The spray foam is virtually identical to the expanded poly urethane of which the insulated walls are made of.

So the additional fire risk is nil.

Further the topside is corked by the 4-square.

As for an internal ignition source...

You'd be talking sabotage.

In which case, nothing we build is immune from that.

The purpose of the seal is to stop heat entry into the chiller. Expanded foam has to beat Chico for such a purpose.

In all my days, I can never recall anyone needing to add additional conductors to a chiller penetration.

Mike,



Sounds good.

Could upload a few Plan Pages from some of the Cold Storage Warehouse Project Design / Engineering Jobs in my Archives.
The Plan Pages would be "PDF Plot Files", not AutoCAD Files, so anyone could view them.

Need to alter the Client / Contractor information in the Title Block, but this will not affect the layout.

I am thinking of these Plan Sheets to upload:

1. Refrigeration Equipment Power Plan,
2. Refrigeration Controls Plan,
3. Details Sheet.

Hopefully I can upload these Sheets as PDFs, instead of a Graphic (Image) File Format.
The Sheets are to be Plotted on ARCH E size Media (30"x42"), so this might present issues if viewed directly in a Web Browser, as a Graphic (Raster) File Format.

If things work out well, viewing may be done in separate Browser Tabs, via a PDF viewing Utility or Plug-In.

Will reply with results.

-- Scott

Electrical Plan Set Sheets follow-up:

Successfully uploaded (3) PDF Plot Files for review.


Go to Electrical Planset- Refrigeration Equipment, at the Technical Reference Section, for viewing, download and descriptions of the Plans.

---edit note:
Will have to add descriptions later this weekend... I am supposed to leave soon for an event I just found out about!


A little background per the uploaded Drawings:

The Uploaded Electrical Plan Sheets are (3) of the Total (10) Sheets that comprise the Electrical Construction Plan Set, for an Electrical Design-Build Tenant Improvement Project performed last Year.
Project is for a well-known and repeat Business Client's new Regional Distribution Center.

The T.I. Project consists of new Cold Storage Facilities within an existing 462,000 Sq. Ft. Concrete Tilt-Up Warehouse Building.
Warehouse Roof Decking is between +45 and +55 Feet Above Finished Floor (A.F.F.).

The Square Footage of this Improvement covers 40,950 Sq. Ft.: 39,500 Sq. Ft. of the Building, and 1,450 Sq. Ft. of the exterior Loading Dock area, for the Refrigeration Equipment (Evaporative Condenser plus the Refrigeration Equipment Rack).

New +40ºF Loading Dock:
Area = 10,000 Sq. Ft.
Ceiling (Lid) Height = +24'-0" A.F.F.

New +34ºF Warehouse Cooler:
Area = 12,500 Sq. Ft.
Ceiling (Lid) Height = +40'-0" A.F.F.

New -10ºF Warehouse Freezer:
Area = 17,000 Sq. Ft.
Ceiling (Lid) Height = +40'-0" A.F.F.

This T.I. is more simpler than the majority of Projects I perform Design / Engineering work on, which is why I chose to use this Project for examples.

........................................................

The Uploaded Plan Sheets were from a "Conceptual" Design Development Plan set Version ("1st draft"). Electrical Plan set was later revised about 6 times due to Client, Vendor and Subcontractor Changes.

For the most part, changes were not too dramatic for the other Trades, but quite dramatic on my side. Revisions per Evaporator layouts affected not only the Penetration Points, but greatly affected the Lighting Layout.
The last Revision was strictly Lighting Fixture Placements - so as to clear the Proposed Fire Sprinklers' Layout.
The Fire Sprinkler Design Engineer and I worked together via E-mailed Layouts, for about 3 Days.
She was in Wisconsin, me in California.

Almost forgot... The Title Block Entries have been greatly edited, to remove Company / Client Information.
Title Block Text has been replaced with Humorous Client / Designer-Builder information.

---BTW---
I could upload the remaining (7) Plan Sheets if needed or preferred.
These Sheets are:

1. Cover Sheet / Scope of Work,
2. Site Plan / Building Footprint,
3. Lighting Compliance Forms,
4. 1 Line Diagram,
5. Panel Schedules,
6. Lighting Circuitry Plan,
7. Lighting Fixture Layout / Dimensions Plan.

Feel free to reply with questions &/or comments.

I hope everyone enjoys the drawings.

-- Scott

El'BUMPO

Mike (Trumpy) and schenimann

Did you guys check out the uploaded PDF Plot Files?

Did anyone look at them???


Things got side tracked per the Sealant, so I am unsure if anyone has interest in this topic still.

-- Scott

Scott:

Yes, I looked at them.

A few design pros that submit plans to me should look at them!!

As ususl, well done....."medium rare" is what comes in my office on first & sometimes second submittals.

I did and filed them in the back of my head for the next time I have to design a tree cooler, but it has been a while since I have done one of them (at least 10 years) so I just gave them a cursory glance. As always I am impressed by the completeness and quality of your responses.

Shane

John and Shane;

Thanks for the replies, for viewing the Posted Documents; and most of all, the positive comments!



-- Scott

I have look at scott's drawing as well that is a really good workmanship and did cover all the details in there IMO that should be a stanard pratice to do that.

Merci,
Marc

Marc,

Once again, Thanks for the nice reply!

-- Scott