The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
230 or 345 kV transmission lines?
by Vlado
Yesterday at 09:33 AM
breaker meltdown
by crselectric
Yesterday at 12:42 AM
Electrical mast flashing product
by ThomasWinfrey
09/22/16 12:14 AM
What estimating software do you recommend?
by sparky
09/21/16 07:20 PM
"Dry Run" Inspection goes awry
by HotLine1
09/20/16 07:39 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
HotLine1 17
gfretwell 9
sparky 9
sparky66wv 8
Vlado 6
Who's Online
1 registered (geoff in UK), 231 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#194004 - 05/04/10 04:21 PM Demand factors for refrigerators in a laboratory
Bravo Offline
Member

Registered: 05/04/10
Posts: 30
Loc: 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.

Top
2014 / 2011 NEC & Related Books and Study Guides
#194006 - 05/04/10 05:03 PM Re: Demand factors for refrigerators in a laboratory [Re: Bravo]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: 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

Top
#194024 - 05/05/10 07:12 AM Re: Demand factors for refrigerators in a laboratory [Re: gfretwell]
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: 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

Top
#194032 - 05/05/10 11:45 AM Re: Demand factors for refrigerators in a laboratory [Re: George Little]
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6785
Loc: Brick, NJ USA
Agree with Greg and George!
_________________________
John

Top
#194035 - 05/05/10 01:24 PM Re: Demand factors for refrigerators in a laboratory [Re: HotLine1]
ghost307 Offline
Member

Registered: 05/09/05
Posts: 876
Loc: 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

Top
#194049 - 05/06/10 09:28 AM Re: Demand factors for refrigerators in a laboratory [Re: ghost307]
Bravo Offline
Member

Registered: 05/04/10
Posts: 30
Loc: NY, USA
thanks guys. I will size 125% of the biggest motor plus 100% of the remainders.

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals