Refrigeration equipment

[WestAL]

After years of working for other companies, I have finally gone into business for myself. I am based out of a small town in west Alabama, serving a market that has been under served for years. I have done several smaller service jobs, and have pretty well for myself since opening my doors. I had the owner of a local grocery store approach me about a new refrigeration project he has.

He has bought a refurbished refrigeration 'rack' for his coolers. It will be set on a new pad they are pouring on the back of the building. After the rack is in place, they will build a room around it to protect all the refrigeration equipment.

I have spoken with the installer, and he has informed me that it requires a 225 amp three phase circuit. The installer's electrician looked at it, and was going to come off an existing 400 amp breaker in the switch gear. This breaker feeds a deli that is no longer in use, but they would still like to have some power going to it, as they want to be able to turn into storage, and have a small office area. I have explained to them that if we were to do the work the way they are asking, they loose the capability to ever run any more of their large kitchen equipment. They understand and want me to proceed with an estimate on the electrical work.

The deli is fed with parallel runs of 250 mcm, the lugs of the breaker look like they are only big enough for 250. If I were to size my wire to the 400 amp breaker that is there now, I would have to pull 500 to the new rack system, set a fused disconnect, and step it down to 225 rated wire going into the rack. I can't fit the 500 on the lugs that are on the breaker.

The other problem that I am dealing with, is that if I were to take one set of the wires going to the deli loose, the the other set is no longer rated for 400 amps. Does anyone see any way around these issues or am I just fighting a losing battle?

The only inspector in the area is the general building inspector, and he has already said that I am more knowledgeable in the electrical field than he is. He will pass me as long everything looks safe.

I want to do this right, and since there is no electrical code in this area, all I have to fall back on is NEC. I would rather walk away from the work that put my name and reputation on something that could bite me later on.​

 

[Pizza]

I assume your pulling aluminum?
500 mcm is good for 310 amps.
Kenya change the breaker to a 225 amp?
Kenya use your 10' feeder tap rule, set a fusable disco and then run 300 mcm to your refrigeration equip. Get a disco with right size lugz.


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[mgookin]

... than put my name and reputation on something that could bite me later on.​

Welcome to the forums and wishing you the highest level of success with your new venture.

If I still worked in a bldg dept today and you told me what you just posted, I'd require a full set of plans with calculations. You need to know the existing service will carry the proposed loads plus all the existing loads. In a rural area with not much for code requirements & compliance, there's no telling what's been done over the years. Taking the time to do this will go a long way in preventing that "bite later on" as you say. Since there's apparently nobody at the bldg dept qualified to review your design & calcs, a peer review would be in order. That can even be done on here.

My advice: Draw it all up. Do the calculations to make sure you're not overloading something.

Also, if he ever wants to do kitchen operations, converting to gas is one option to consider. If nothing else he can throw that out to a prospective buyer if he ever wants to sell the place.

 

[WestAL]

Thanks for the responses, guys.

I have talked with another master, who I used to work with. The two of us can usually bounce ideas off each other and come up with something. That is what I miss about working with other folks, is having some one to peer review some of the things that we are doing.

I think I have settled on setting a 400 amp main lug sub panel on the other side of the wall. It will be within 10' of the switch gear and fed from the unused breaker. I can then feed the refrigeration from a 225 amp breaker with 225 amp rated wire. The equipment has its own disconnect mounted to the unit. I can also feed one run of 250 to go back to the deli panel. I'm going today to look at stepping the breaker size of the deli down to correspond to only having one run of 250 feeding it.

I have spoken with the owners multiple times, and they are dead set on using their deli breaker to feed the new refrigeration equipment. I told them that the only way that I would do this, is if I can satisfy my code requirements. We will see what they think of my bid with the new subpanel and breakers.

 

[growler]

I can then feed the refrigeration from a 225 amp breaker with 225 amp rated wire. The equipment has its own disconnect mounted to the unit.

If that refrigeration equipment is protected by a 225 amp breaker it's probably not pulling anything close to that after start up. You need to know the actual full load amps of this equipment and this will give a better idea of what you are dealing with for your calculations.