hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
I have disconnect inside walk in freezer. Quick question what is the typical nema rating for disconnect inside walk-in freezer?
Nema rating disconnect
- Thread starter hhsting
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hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
I would say NEMA 3RX but I have seen some AHJs not care if it is NEMA 1.
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
Or 4X
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
OR type 6 or similar water-tight enclosures.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Why such extremes?
4X is for corrosive environments. Type 6 is for submersion at limited depth.
Any of the Type 3 version are rated for damp and operation with ice covered.
My preference would probably be a combination 3R/12 style, but forr a restaurant style operation any outdoor device would be okay.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Until the door is left open, like during loading/unloading, then the humidity builds up pretty fast.
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
just options. they all work.
I don't know what they plan to do in the freezer. I have seen places do some food processing in freezers or hose them down occasionally. They needed disconnects for the processing equipment. NEMA 4 or 6.
If it is just dry freezer foods being stored like in a grocery store then it likely won't matter.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Never a need for Type 6 unless it is being submerged.
Typically a Type 4 meets most requirements, although finding a Type 4X is probably easier.
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
This walk in freezer is in restaurant.
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
But does that humidity cause rain on your equipment inside? If it does, I could see requiring 3R, otherwise seems like Type 1 would suffice.
On the other hand, if that humidity can penetrate the equipment before condensing inside, maybe an enclosure type that would prevent the entrance of ambient air is appropriate?
Cheers, Wayne
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
I have seen some Nema 1 enclosures fully rusted or pitted out in walk-ins / cold rooms. But it was industrial and there was discussion that the area was being hosed down or brought to room temp daily creating condensation on the terminals and wires.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Non-metallic makes sense for these type of environment. Personally, I don't like any electrical in most small walk-in freezers
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Would not nema 4X be good for walkin freezer in restaurant or nema 3R? Which?
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hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
No one
Use NEMA 3 which is overkill but will have you covered. If you get a chance, go into a walk in freezer and look at the evaporator(s), their wiring is open and NEMA 1 at best.
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
The OP's job is as a plan reviewer. So the question is whether a NEMA 1 disconnect (or lack of specification on the plans requiring something other than NEMA 1) should be rejected at plan review or not.
Cheers, Wayne