ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
sparky 5
Recent Posts
Holiday Wishes to all!!
by HotLine1. 12/15/17 07:20 PM
Dimmable LED 2x4 lay in fixtures
by HotLine1. 12/15/17 07:15 PM
2017 NEC Changes
by HotLine1. 12/15/17 07:06 PM
Casino Wiring methods
by HotLine1. 12/09/17 10:44 AM
Ground wire Size to water Line.
by HotLine1. 12/05/17 12:11 PM
New in the Gallery:
Gallery Test
Popular Topics(Views)
243,063 Are you busy
179,502 Re: Forum
170,424 Need opinion
Who's Online Now
0 registered members (), 14 guests, and 10 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#94204 - 07/17/05 10:31 AM h20 heaters  
watersparkfalls  Offline
Member
Joined: Mar 2005
Posts: 222
Washington...Not DC
a friend asked me if a 125 amp sub panel would be ok for three water heaters that are 40 amps each.


2017 / 2014 NEC & Related Books and Study Guides

#94205 - 07/17/05 10:51 AM Re: h20 heaters  
Larry Fine  Offline
Member
Joined: Feb 2005
Posts: 693
Richmond, VA
Is the 40 amps the actual heater current, or the individual circuit ratings?


Larry Fine
Fine Electric Co.
fineelectricco.com

#94206 - 07/17/05 10:56 AM Re: h20 heaters  
watersparkfalls  Offline
Member
Joined: Mar 2005
Posts: 222
Washington...Not DC
individual circuit ratings


#94207 - 07/17/05 11:30 AM Re: h20 heaters  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Really comes down to the application.

If you're talking about water heaters used as household ones are....heating separate systems, and used occasionally for brief periods, the 125 amp panel should be fine.

If these are used together, as in supplying hot water to a production process, and use continuously, than you have to treat the loads as continuous, and have that 25% "buffer' added in to both your panel and the wire supplying it.
(Use the KW ratings of the heaters for your calcs).


#94208 - 07/17/05 05:24 PM Re: h20 heaters  
Larry Fine  Offline
Member
Joined: Feb 2005
Posts: 693
Richmond, VA
At max proper circuit loading, which would be (40a. x 80%) 32a. each, that's 96 a. total.

Another way, 3 x 40a. = 120a. Either way, you're okay.


Larry Fine
Fine Electric Co.
fineelectricco.com


Member Spotlight
waymag
waymag
dallas, texas, USA
Posts: 67
Joined: January 2002
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: 0.011s Queries: 14 (0.002s) Memory: 0.7679 MB (Peak: 0.9069 MB) Zlib enabled. Server Time: 2017-12-16 03:11:09 UTC