ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
twh 10
Admin 4
Recent Posts
Windows 10, who's upgraded?
by geoff in UK. 05/29/17 01:05 PM
How do you find a good employee?
by ElectricianBud. 05/27/17 10:58 AM
Recall notice: Bosch Solar panels
by ElectricianBud. 05/27/17 10:53 AM
Correct rotation, wrong sequence
by Potseal. 05/27/17 12:15 AM
Dryer, Range grounding from "Main" panel
by sparkync. 05/25/17 05:49 PM
New in the Gallery:
SE cable question
Popular Topics(Views)
237,001 Are you busy
172,018 Re: Forum
164,894 Need opinion
Who's Online Now
0 registered members (), 46 guests, and 9 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#94204 - 07/17/05 11:31 AM h20 heaters  
watersparkfalls  Offline
Member
Joined: Mar 2005
Posts: 216
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 11:51 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 11:56 AM Re: h20 heaters  
watersparkfalls  Offline
Member
Joined: Mar 2005
Posts: 216
Washington...Not DC
individual circuit ratings


#94207 - 07/17/05 12:30 PM 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 06:24 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
Bill Addiss
Bill Addiss
NY, USA
Posts: 3,878
Joined: October 2000
Show All Member Profiles 
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.014s Queries: 14 (0.004s) Memory: 0.7673 MB (Peak: 0.9072 MB) Zlib enabled. Server Time: 2017-05-30 07:17:40 UTC