# Walk in coolers



## WronGun (Oct 18, 2013)

I have a project starting that involves wiring a large wall in cooler. I’m not so concerned with the lighting but the cooling system. 

4 in-cooler fan units and 3 rooftop units it’s easy enough to read name plates and bring the required power. However , I know there is more to that. 

Is it normal to get into any control work or does the refrigeration company do this? 

Im not responsible for any efficiency systems, just powering the units up (stated in my contract). 

I’ve spent some time reading what I can on google but still nervous as to what I’m walking into. As I’ve never done a walk in cooler of this type or size (30 doors) 

I guess I’m asking if this can get too technical for a novice in refrigeration wiring 





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## telsa (May 22, 2015)

You're describing factory assembled compressor assemblies -- I believe.

In which case, the mechanical dudes figure to have the controls contract, and you're just going to be bringing in big feeders.

Get more details from the EEs on what's up.

Be prepared to see copper conductors specified by contract, etc.

If you want to slam this puppy out, stay with factory elbows. ( feeder sizes, of course )


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## joebanana (Dec 21, 2010)

Piece of cake. power to the RTU's, power to the FAU, and a lighting ckt. Talk to the refer. guy first.


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## MechanicalDVR (Dec 29, 2007)

The evaps (indoor units) will be on one circuit each, if they have electric defrost. If it's hot gas defrost they will draw relatively small current.

The condensing units (outdoors) will be large ampacities. 

If the solenoid valves are line voltage you may need to wire those but that should be arranged before you start.


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## WronGun (Oct 18, 2013)

joebanana said:


> Piece of cake. power to the RTU's, power to the FAU, and a lighting ckt. Talk to the refer. guy first.




That’s what I thought until google spooked me out. 

Signal wires , door heaters , etc, etc, etc. I lost track of all the possibilities. 




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## MechanicalDVR (Dec 29, 2007)

WronGun said:


> That’s what I thought until google spooked me out.
> 
> Signal wires , door heaters , etc, etc, etc. I lost track of all the possibilities.


Door (mullion) heaters are on the lighting circuit and draw next to nothing.


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## MechanicalDVR (Dec 29, 2007)

joebanana said:


> Piece of cake. power to the RTU's, power to the FAU, and a lighting ckt. Talk to the refer. guy first.


What the hell is a FAU?

You mean FCU?


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## WronGun (Oct 18, 2013)

I hope it goes well. 

I’m sure I’ll have more questions, it sounds straight forward. 


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## joebanana (Dec 21, 2010)

MechanicalDVR said:


> What the hell is a FAU?
> 
> You mean FCU?


Forced Air Unit. Or, evap.


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## joebanana (Dec 21, 2010)

WronGun said:


> That’s what I thought until google spooked me out.
> 
> Signal wires , door heaters , etc, etc, etc. I lost track of all the possibilities.
> 
> ...


Don't forget the EXO-disco at the RTU.


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## WronGun (Oct 18, 2013)

joebanana said:


> Don't forget the EXO-disco at the RTU.




What is EXO? 


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## joebanana (Dec 21, 2010)

WronGun said:


> What is EXO?
> 
> 
> Sent from my iPhone using Tapatalk


Externally operable. They require them out here.


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## WronGun (Oct 18, 2013)

joebanana said:


> Externally operable. They require them out here.




Ok , yes planned on this 


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## macmikeman (Jan 23, 2007)

I did a zillion walk in's . Door heater, light and switch, power to fan coil and heater tape to keep the drain pipe from freezing over. Then there is a 4 wire with ground control between the fan coil and the rooftop compressor. XN34 is the contacts on the time clock that correspond to the fan coil units terminals. Don't cross em up, use a different color for each wire. (probably all replaced with plc type controls nowadays, hey I'm an old dinosaur what can I say, haven't done any lately, my connection to the refrigeration business died from colon cancer six years ago. I always did all their cooler boxes since the day they started the company till the day he died. Wife sold the business to a nice guy who has fifty electrician cousins from the Philippines who will work cheap. 


Don't drill any holes in the bottom side of the fan coil units, that is a drain pan down there..............


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## WronGun (Oct 18, 2013)

macmikeman said:


> I did a zillion walk in's . Door heater, light and switch, power to fan coil and heater tape to keep the drain pipe from freezing over. Then there is a 4 wire with ground control between the fan coil and the rooftop compressor. XN34 is the contacts on the time clock that correspond to the fan coil units terminals. Don't cross em up, use a different color for each wire. (probably all replaced with plc type controls nowadays, hey I'm an old dinosaur what can I say, haven't done any lately, my connection to the refrigeration business died from colon cancer six years ago. I always did all their cooler boxes since the day they started the company till the day he died. Wife sold the business to a nice guy who has fifty electrician cousins from the Philippines who will work cheap.
> 
> 
> 
> ...




Ok 

Sounds like I’ll have to run an additional pipe from the cooler to the roof with 3 Control wires.

Did you install pvc or rain tight emt in your coolers ?


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## MechanicalDVR (Dec 29, 2007)

joebanana said:


> Forced Air Unit. Or, evap.


Never called an evaporator for a walk in a forced air unit as that term usually is for a ducted discharge air handler.

Maybe that's just some regional slang.

Some do call them 'fan coil units'.


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## cdslotz (Jun 10, 2008)

Did you include just power feeds in your estimate and qualify?


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## macmikeman (Jan 23, 2007)

WronGun said:


> Ok
> 
> Sounds like I’ll have to run an additional pipe from the cooler to the roof with 3 Control wires.
> 
> ...



4 wires + ground. I used emt always.

Left something out. For freezers if you penetrate the box you need to seal up your conduits afterwards to prevent ice buildup inside the conduits and electrical equipment. I've used duct seal , expanding foam, dap, silicone. The best has been expanding foam. Ask your inspector though which sealant he approves before hand. Silicone seal any screws inside you use to clamp conduits to the box. Carflex inside the boxes is the way to go. Liquid tite non metallic flex for the code nazi's .


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## mgraw (Jan 14, 2011)

There is a lot of guessing going on here. The fan coils may need to be connected electrically to the condenser or they may not. There may be a line voltage t-stat and/or a line voltage solenoid. There probably are door and/or frame heaters. Talk to the refrigeration guy and find out exactly what you need.


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## MechanicalDVR (Dec 29, 2007)

mgraw said:


> There is a lot of guessing going on here. The fan coils may need to be connected electrically to the condenser or they may not. There may be a line voltage t-stat and/or a line voltage solenoid. There probably are door and/or frame heaters. Talk to the refrigeration guy and find out exactly what you need.


Evaps for a walk in are only extremely rarely connected electrically to the condenser, other than for some types of defrost.

The norm is a solenoid on the liquid line coming into the evap that is controlled by a thermostat inside the box. 

The condenser operates indepently off it's own pressure control.


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## WronGun (Oct 18, 2013)

MechanicalDVR said:


> Evaps for a walk in are only extremely rarely connected electrically to the condenser, other than for some types of defrost.
> 
> 
> 
> ...




I will touch base with the refrigeration tech to make sure. Once this part of the job is out of the way the rest is basic fitup , and security.... I will be more relaxed  


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## joebanana (Dec 21, 2010)

MechanicalDVR said:


> Never called an evaporator for a walk in a forced air unit as that term usually is for a ducted discharge air handler.
> 
> Maybe that's just some regional slang.
> 
> Some do call them 'fan coil units'.


Just a generic term for 'not the condenser'.


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## MechanicalDVR (Dec 29, 2007)

WronGun said:


> I will touch base with the refrigeration tech to make sure. Once this part of the job is out of the way the rest is basic fitup , and security.... I will be more relaxed


Sounds like a plan, let us know how they are going to be when you find out.


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## MechanicalDVR (Dec 29, 2007)

joebanana said:


> Just a generic term for 'not the condenser'.


I see that but it has to be a west coast thing.


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## mgraw (Jan 14, 2011)

MechanicalDVR said:


> Evaps for a walk in are only extremely rarely connected electrically to the condenser, other than for some types of defrost.
> 
> The norm is a solenoid on the liquid line coming into the evap that is controlled by a thermostat inside the box.
> 
> The condenser operates indepently off it's own pressure control.


Yep I have only installed a few hundred of them over the years(both electrical and refrigeration) so I am sure I have not seen it all.

What you said is the most common but it is not the only way. That is why I said to talk to the refrigeration people.


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## WronGun (Oct 18, 2013)

Is it necessary to have a service GFCI Receptacle at all 3 rooftops ? 

They are side by side about 10’ apart from each other 


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## MechanicalDVR (Dec 29, 2007)

WronGun said:


> Is it necessary to have a service GFCI Receptacle at all 3 rooftops ?
> 
> They are side by side about 10’ apart from each other
> 
> ...


You should be good, I think it just has to be within 25'.

Not sure what state you are in but NJ requires a light fixture as well.


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## MTW (Aug 28, 2013)

I can wire refrigeration equipment with one hand tied behind my back and a blindfold on.


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## Galt (Sep 11, 2013)

and size and run all the tubing and evacuate and add the refrigerant


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## WronGun (Oct 18, 2013)

MTW said:


> I can wire refrigeration equipment with one hand tied behind my back and a blindfold on.




If you can wire the lights at the same time with your other hand I’d like to offer a job position with my company. Let me know if interested I’ll forward a digital application. 


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## lighterup (Jun 14, 2013)

WronGun said:


> If you can wire the lights at the same time with your other hand I’d like to offer a job position with my company. Let me know if interested I’ll forward a digital application.
> 
> 
> Sent from my iPhone using Tapatalk


I do believe he is looking...soooo


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## MechanicalDVR (Dec 29, 2007)

lighterup said:


> I do believe he is looking...soooo


Good thing about a forum like this.


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## WronGun (Oct 18, 2013)

Ok here goes, another question ...

The RTU’s are marked 200-230v 3ph

The panel shows 240v Max 3ph.

What does 240MAX actually mean. 




They Also have ice machines and bottle recycle machines that are tagged 208V 3ph. 

There is not a 208v Panel 


All I have is 347/600v Panel and a transformer for square D panel pictured below 





Panel 











Recycle machines 











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## MechanicalDVR (Dec 29, 2007)

WronGun said:


> Ok here goes, another question ...
> 
> The RTU’s are marked 200-230v 3ph
> 
> ...



What is the actual voltage phase to phase you are reading on the panel?


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## macmikeman (Jan 23, 2007)

MechanicalDVR said:


> What is the actual voltage phase to phase you are reading on the panel?


Bingo winner! It is probably going to be 208 wye. Max means up to in panel land. You cannot hook up to a 480 volt secondary with that panel or breakers. But a 208/120 is fine since it's less than 240 volts. P.S. 240 MAX means 240v nominal. It will reach a higher voltage for 240 twice each cycle, x60 for 60hz systems. But most of the time it will average 240 volts, and anyway if you use a Knopp volt tester like real manly man above superior intelligence peoples in this trade do, it won't read the higher end of the cycles. They did that on purpose so that you would get a good restful sleep at night.


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## MechanicalDVR (Dec 29, 2007)

macmikeman said:


> Bingo winner! It is probably going to be 208 wye. Max means up to in panel land. You cannot hook up to a 480 volt secondary with that panel or breakers. But a 208/120 is fine since it's less than 240 volts. P.S. 240 MAX means 240v nominal. It will reach a higher voltage for 240 twice each cycle, x60 for 60hz systems. But most of the time it will average 240 volts, and anyway if you use a Knopp volt tester like real manly man above superior intelligence peoples in this trade do, it won't read the higher end of the cycles. They did that on purpose so that you would get a good restful sleep at night.


Yeah man, taking a real reading as opposed to reading a label is always best.


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## 460 Delta (May 9, 2018)

Uhh, mac, real manly men use a Simpson 260. IMHO.


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## MechanicalDVR (Dec 29, 2007)

460 Delta said:


> Uhh, mac, real manly men use a Simpson 260. IMHO.


You leave out the less than manly ones that just have a good apprentice to carry their tools.


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## 460 Delta (May 9, 2018)

You’re right mech, if I had an apprentice they would pack my 260, Sperry Snap 9 and my hand crank Biddle megger. Alas I’m without a apprentice 😞


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## macmikeman (Jan 23, 2007)

460 Delta said:


> Uhh, mac, real manly men use a Simpson 260. IMHO.


I admit, those were great. I had one given to me in vocational school. 1975-6. I don't recall where along the line I lost it or it was "borrowed" or if it just died. I don't have one now though.


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## MechanicalDVR (Dec 29, 2007)

macmikeman said:


> I admit, those were great. I had one given to me in vocational school. 1975-6. I don't recall where along the line I lost it or it was "borrowed" or if it just died. I don't have one now though.


Must have been loaned or stolen.

I think they had to be shot with a rifle round to die.


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## WronGun (Oct 18, 2013)

Yes it is 208v.. thinking back, it makes sense.. it’s amazing all the years of working in the field of simply following directions and looking at plans so detailed it’s like color by numbers. It’s like that on very large highly engineered jobs...


This entry level commercial jobs have been requiring so much more planning. 
now I’m spending all day reading name plates and Doing code calculations..... 


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## WronGun (Oct 18, 2013)

Do these RTU’s normally run at the same time ? 

Im checking load calcs as they’ve added additional smaller fridges, etc.

The panel Main has a 100A breaker and is being stepped down from a square D xformer coming from a 347/600 Panel. 

I’ve never had to size an xformer before so if it needs changing I may need some help. 

Tomorrow morning I’m going to get the exact specs off the xformer 

But it seems the cooler alone would require an upgrade from 100A 




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## sparkiez (Aug 1, 2015)

WronGun said:


> Do these RTU’s normally run at the same time ?
> 
> Im checking load calcs as they’ve added additional smaller fridges, etc.
> 
> ...


Sounds to me like you're in the money now.


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## WronGun (Oct 18, 2013)

Transformer rated 83.3A and is being fed from a 3-phase 45A Breaker

Now I’m truly in new territory.

3 RTU’s
6 cooler fans 
Lighting 

Additional smaller loads , without calculating at this moment seems I need to upsize. 












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## WronGun (Oct 18, 2013)

I’ll be honest , I don’t know a damn thing about sizing transformers. I only have experience installing them.

Here is a quick load calc I did and came up with upgrading to a 75KVA 

I think it looks good but would like some input from some of you more experienced fellows.













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## catsparky1 (Sep 24, 2013)

I am doing a packing house with a 5000 square drive in cooler . 
It has 3 three phase condensers , 3 120 fans , 8 LED high bays , 120 heat tape on doors .1 3 phase bin dumper , 3 conveyer lines 120 volt with VFDs . All of this runs 24-7 for a couple months a year and needs a 100 amp sub . Total load is around 70 amps .


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## WronGun (Oct 18, 2013)

This is a 15,000 sq’ liquor store with only a 100A panel and it seems the cooler alone is going to eat up a good portion of the power. 

Most of it is just lighting ofcourse. Cooler appliances are most of the load. 


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## Ctsparky93 (Sep 17, 2016)

How did you get the 208/20a is 10kva for the rtu? I am assuming it’s 3 phase but the math still is off


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## WronGun (Oct 18, 2013)

Ctsparky93 said:


> How did you get the 208/20a is 10kva for the rtu? I am assuming it’s 3 phase but the math still is off
> 
> 
> Sent from my iPhone using Tapatalk




It’s 3-phase

I did it over and got 7.2 


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## catsparky1 (Sep 24, 2013)

Did you mean 1500 square ? The average convenience store is 4000 square . small grocery store is 15,000 . I have done some little mini markets with 2 100 amp 3 phase panels . when they add a gas station 400 or 600 amp service but 15,000 square 1200 amp 120-208 service .


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## WronGun (Oct 18, 2013)

No I mean 15,000 sq’ 

This place is like a giant state liquor store. 

8,000 sq’ of it is just overstock storage (just high bay lighting)

7,000 is retail Space 

Most of the floor space is just lighting load. 

The power is from coolers , and front end area 

The lighting comes from the high voltage panel not the step down sub 

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## WronGun (Oct 18, 2013)

I’m still pushing the power pretty close to its limits 

35-40KVA and it’s rated 30kVA


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## Ctsparky93 (Sep 17, 2016)

Is it possible they could get some of the equipment in 480v if not just add a 75 kva transformer with a 200 amp panel if there is space. Or replace that 30 with 75 and make the 100amp panel a sub panel.


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## WronGun (Oct 18, 2013)

Ctsparky93 said:


> Is it possible they could get some of the equipment in 480v if not just add a 75 kva transformer with a 200 amp panel if there is space. Or replace that 30 with 75 and make the 100amp panel a sub panel.
> 
> 
> Sent from my iPhone using Tapatalk




The panel is already rated for up to 225A

I would just need to change the 100A breaker on it , the conductors and xformer...

Equipment was already ordered before i was involved in anything. 


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## WronGun (Oct 18, 2013)

I will start a new thread on this hopefully I can get some more input 


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## Ctsparky93 (Sep 17, 2016)

So in your calculations how did you get the amps and kva? All those look off now that I look closer. But if a 15000 sq store only has a 100 amp panel I am sure most of that is being used a 30 kva is only good for 83 anyways. So it looks like you need a new transformer. 


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## WronGun (Oct 18, 2013)

Ok , 

Here is the layout of exactly what I have with my corrections.


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## WronGun (Oct 18, 2013)

Ctsparky93 said:


> So in your calculations how did you get the amps and kva? All those look off now that I look closer. But if a 15000 sq store only has a 100 amp panel I am sure most of that is being used a 30 kva is only good for 83 anyways. So it looks like you need a new transformer.
> 
> 
> Sent from my iPhone using Tapatalk




To get KVA I just did the equation for 3-phase 

KVA= VOLTS x AMPS x Square Root of 3 / 1000

KVA single phase 

KVA = Volts x Amps / 1000



Also , the main lighting and HVAC RTU come from the 277/480 side 

Just outlets and small bathrooms come from the 120/208




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## Ctsparky93 (Sep 17, 2016)

I did the math and you get a total of 41678 kva needed. No matter what old transformer is to small. Also you said the store only has a 100amp 480/277? Did you do a load calc for the store? 


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## WronGun (Oct 18, 2013)

Ctsparky93 said:


> I did the math and you get a total of 41678 kva needed. No matter what old transformer is to small. Also you said the store only has a 100amp 480/277? Did you do a load calc for the store?
> 
> 
> Sent from my iPhone using Tapatalk




I did not do a load calc on the main. I will tomorrow. There are a few items on it.










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## WronGun (Oct 18, 2013)

This is only a 100A/480v service back to the meter. 

The Main has 2 lighting circuits and (2) RTU’s Which have 35A OCPD. I have not made it up to the roof to check name plates. 
That is all. 

Meter is 200’ away and it’s all piped in 1 1/4” 


The only other option is a 480v/200A Panel about 80’ away and is a clear shot with wide open racks already in place. This panel
Has 1 RTU circuit and 1 lighting circuit only 

This other 200A panel is actually part of the adjacent unit , but the tenant leased both units for this business. 

I would assume he will need permission from building owner if they want to mix electrical between both units. 


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## WronGun (Oct 18, 2013)

I know there were some suggestions on 1 circuit per interior fan but the refrigeration company installs 1 timer per 2 fans. Also the calculations suggest 2 fans per circuit is still under load. 


Update on last few posts :

We ended up bringing new 480V/200A feeds Into a disco then a new 75KVA xformer and updating the 120/208 tub to fit a 200A ML Kit. 


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