Electrician Talk - Professional Electrical Contractors Forum concuctor sizing
 User Name Remember Me? Password
 Register Electrical Photos FAQ Members List Social Groups Contractor Talk Search Today's Posts Mark Forums Read

 Thread Tools Search this Thread Display Modes
 02-21-2008, 09:19 PM #1 Senior Member     Join Date: Feb 2007 Location: CA/MI Posts: 4,396 concuctor sizing I will be installing a 200 amp rated main lug sub panel for a concession stand. The loads are coffee maker, bun warmer, ice machine , water heater, ect. The loads are: phase A- 72 amps B-68 amps and C- 65 amps. What would be the minimum wire size for this and what are the steps to formulate it. I would think it's something like 125% of 72 divided by 1.73? I am not sure but the panel is 90 feet away from source and ran in 1.25 emt. thanks bk __________________ When ls lunch?

Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!
 02-22-2008, 06:44 AM #2 I Love My Job     Join Date: Aug 2007 Location: St. Cloud, Fl Posts: 1,279 I based my calcs off 200A because you know it will be added to down the road. At 200A I came up with 250MCM because I'm assuming The majority of the loads are linear. I didn't derate because of that but I did a correction of .82 temperature, I calculated the VD (based on 208 3Ph.) at 100' and it was negligible. The only problem is you can not get 250's in the pipe. But at 90A with a temp correction of .82 you could pull #1 CU. Based off the 60c column because it is less than 100A. But you should bump the EMT to 1.5 because the you can only put 4 #1's in 1.25 EMT and you need 5 conductors; 3ph's, a neutral, and a ground. __________________ Memorial Day: All gave some but some gave all. Take the time to tell a Veteran Thank You, You owe him/her at least that much. After all Freedom is not Free. Last edited by Greg; 02-22-2008 at 06:47 AM.
 02-22-2008, 10:41 AM #3 Senior Member     Join Date: Feb 2007 Location: CA/MI Posts: 4,396 Well I am not pulling 250's thats for sure, and it's one solid run of 1.25 emt so I do not need a ground wire either. I was hoping I could get away with at least #2's. __________________ When ls lunch?
 02-22-2008, 11:29 AM #4 Senior Member   Join Date: Dec 2007 Posts: 1,967 I'd say #2 or #1 copper, THW-2 should be more than adequate and I'm not too sure #3 THW-2 wouldn't be adequate.
03-02-2008, 06:41 PM   #5
Junior Member

Join Date: Dec 2007
Location: North Central Texas
Posts: 27

Quote:
 Originally Posted by Bkessler I will be installing a 200 amp rated main lug sub panel for a concession stand.
Why are you using a 200A panel for a 72A load? I'd use a 100A or 125A if I needed the spaces.

Quote:
 Originally Posted by Bkessler The loads are coffee maker, bun warmer, ice machine , water heater, ect.
Water heater is continuous load at 125%
It's hard to figure the load on "ect."

Quote:
 Originally Posted by Bkessler The loads are: phase A- 72 amps B-68 amps and C- 65 amps.
How did you determine this? Does it include the 125% for the W.H.? Lights?
Is there gonna be any heat? 1500 watt space heaters add up in hurry.

Quote:
 Originally Posted by Bkessler What would be the minimum wire size for this and what are the steps to formulate it.
Wire size is in Table 310.16.
once you know your actual load you just look it up in the proper column and derate if necessary.

Quote:
 Originally Posted by Bkessler I would think it's something like 125% of 72 divided by 1.73?
Huh?

Quote:
 Originally Posted by Bkessler I am not sure but the panel is 90 feet away from source and ran in 1.25 emt.
90 feet is not far enough to worry about VD.

Quote:
 Originally Posted by Bkessler thanks bk
You're welcome

 Thread Tools Search this Thread Search this Thread: Advanced Search Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post gojuman General Electrical Discussion 7 08-28-2008 12:43 AM Mountain Electrician General Electrical Discussion 23 06-03-2008 06:08 AM Vr_ecobox Services and Service Equipment 1 12-07-2007 07:49 PM Roger123 NEC Code Forum 11 10-18-2007 08:35 PM Roger123 General Electrical Discussion 12 10-12-2007 10:08 AM

Top of Page | View New Posts

All times are GMT -4. The time now is 05:58 AM.

 Contact Us - Electrical Forum - Privacy Statement - Affiliate Disclosure - Terms of Service - Top

Electrician Talk © 2006 - 2010 The Building Network

Search Engine Optimization by vBSEO 3.6.0 RC 2