HVAC package unit

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JDB3

Senior Member
I am in the process of bidding on a job that will have 8 package (all in one) HVAC units. They will have 15 KW of 3 phase (230/120) heat. The information on these units states they will draw 36 amps; 50 amp min. & 60 amp max. over-current protection; #6 copper supply with #10 grounding conductors.

Been a while since I have done any 3 phase. Does the above sound right? :?
 

infinity

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Location
New Jersey
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Journeyman Electrician
The information on these units states 50 amp min. & 60 amp max. over-current protection

This is the relevant information. Unless you're using NM cable you could likely use #8 conductors and a 60 amp OCPD. #6 will work too.
 

JDB3

Senior Member
The work will probably be in EMT to the disconnect & then liquidtight flex to the unit. This is a location where they erase data from "used" phones and get the phones ready for re-furbishing. They have a very high security level at this site (on site guard, wand, walk through detector) as strong as at airports.

Since manufactures spec. #6, I might just use that. OR see about permission to use #8 and then 3/4" conduit (would be nice) .
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
If just the resistive heat is 15KW it seems like the 36 amps is too low. How about the fans and compressors?
 

infinity

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Staff member
Location
New Jersey
Occupation
Journeyman Electrician
The work will probably be in EMT to the disconnect & then liquidtight flex to the unit. This is a location where they erase data from "used" phones and get the phones ready for re-furbishing. They have a very high security level at this site (on site guard, wand, walk through detector) as strong as at airports.

Since manufactures spec. #6, I might just use that. OR see about permission to use #8 and then 3/4" conduit (would be nice) .

Since the MCA is 50 amps, using #8 THHN with EMT will allow you to use the 75° C ampacity of that conductor which is 50 amps but if the spec calls for #6 you will likely need to use that instead.
 
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