ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
dsk 13
Admin 8
doc 3
Recent Posts
Bathroom electrical
by doc. 08/19/17 06:53 AM
electircal ageing test on IPC
by SIAME. 08/15/17 02:43 AM
electrical aging test on IPC
by gfretwell. 08/15/17 12:27 AM
"Line level" audio on Cat 5?
by gfretwell. 08/08/17 10:39 PM
Fire alarm phone lines and color coding
by gfretwell. 08/08/17 10:26 PM
New in the Gallery:
Gallery Test
Popular Topics(Views)
240,033 Are you busy
175,645 Re: Forum
167,877 Need opinion
Who's Online Now
0 registered members (), 89 guests, and 9 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#194004 - 05/04/10 07:21 PM Demand factors for refrigerators in a laboratory  
Bravo  Offline
Member
Joined: May 2010
Posts: 30
NY, USA
Can I apply table 220.56 - demand factors for kitchen equip to laboratory refrigerators? The refrigerators are intermittent in use similiar to kitchen ref's.

thanks in advance.


2017 / 2014 NEC & Related Books and Study Guides

#194006 - 05/04/10 08:03 PM Re: Demand factors for refrigerators in a laboratory [Re: Bravo]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,103
Estero,Fl,usa
I vote no. Refrigerators are basically motors.
I see this being 220.14(C) referencing 430.24

(125% of the biggest motor plus 100% of the rest).

If you are coming back from a power failure every one of those reefers will be presenting LRA at the same time. Depending on where you are, that can be a fairly frequent thing.

I am open to being wrong tho. wink



Greg Fretwell

#194024 - 05/05/10 10:12 AM Re: Demand factors for refrigerators in a laboratory [Re: gfretwell]  
George Little  Offline
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
I'm going to agree with Greg on this one for the reason he mentioned plus if we are talking about refrigeration type equipment there is nothing in Article 440 that I am aware of that allows us to apply a demand factor.


George Little

#194032 - 05/05/10 02:45 PM Re: Demand factors for refrigerators in a laboratory [Re: George Little]  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,858
Brick, NJ USA
Agree with Greg and George!


John

#194035 - 05/05/10 04:24 PM Re: Demand factors for refrigerators in a laboratory [Re: HotLine1]  
ghost307  Offline
Member
Joined: May 2005
Posts: 907
Chicago Illinois USA
Greg bring up an excellent point. After a power failure, that refrigerator will be running as a continuous load until it gets its contents cooled down. Some of that laboratory refrigerators that I've done go down to way below -100 degrees.


Ghost307

#194049 - 05/06/10 12:28 PM Re: Demand factors for refrigerators in a laboratory [Re: ghost307]  
Bravo  Offline
Member
Joined: May 2010
Posts: 30
NY, USA
thanks guys. I will size 125% of the biggest motor plus 100% of the remainders.



Member Spotlight
Tom
Tom
Shinnston, WV USA
Posts: 1,044
Joined: January 2001
Show All Member Profiles 
Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.012s Queries: 15 (0.002s) Memory: 0.7766 MB (Peak: 0.9258 MB) Zlib enabled. Server Time: 2017-08-21 16:06:18 UTC