ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Danish type K Sockets
by dsk - 02/23/20 02:42 AM
15 amp outlets removed due to cell phones
by BigB - 02/20/20 07:23 PM
Square D "All-In-One" Panelboard
by gfretwell - 02/18/20 07:38 PM
2020 code
by shortcircuit - 02/11/20 04:30 PM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 74 guests, and 9 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Water heater calculationsSo when I count calculati #220021 04/11/19 06:23 PM
Joined: Mar 2005
Posts: 233
watersparkfalls Offline OP
Member
My question is I have a 250 gallon Water heater do I calculate at 100% or 125%? This is branch circuit not feeder calculations. Thanks

2017 / 2014 NEC & Related Books and Study Guides
Re: Water heater calculationsSo when I count calculati [Re: watersparkfalls] #220022 04/11/19 06:30 PM
Joined: May 2005
Posts: 984
G
ghost307 Offline
Member
That's a big tank.
Is this for a locker room with showers?


Ghost307
Re: Water heater calculationsSo when I count calculati [Re: watersparkfalls] #220023 04/11/19 06:32 PM
Joined: Mar 2005
Posts: 233
watersparkfalls Offline OP
Member
OK I see article 422.10 says 125% but where is the code reference to the breaker size one size higher? My water heater is listed at 87 A so 90 A is next standard breaker size.

Re: Water heater calculationsSo when I count calculati [Re: watersparkfalls] #220024 04/11/19 06:46 PM
Joined: May 2005
Posts: 984
G
ghost307 Offline
Member
You need to take 125% of the full load current; so it needs to be treated as a 108.75A load.
Make sure to also upsize the wire accordingly.


Ghost307
Re: Water heater calculationsSo when I count calculati [Re: ghost307] #220027 04/13/19 11:42 AM
Joined: Mar 2005
Posts: 233
watersparkfalls Offline OP
Member
Thanks, ghost.
H20

Re: Water heater calculationsSo when I count calculati [Re: ghost307] #220028 04/13/19 11:43 AM
Joined: Mar 2005
Posts: 233
watersparkfalls Offline OP
Member
Yeah exactly gym inside google bldg.
H20


Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

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

 

Member Spotlight
HCE727
HCE727
Delaware County, PA, USA
Posts: 186
Joined: November 2005
Show All Member Profiles 
Top Posters(30 Days)
dsk 9
djk 5
Admin 3
cgw 2
Popular Topics(Views)
263,571 Are you busy
198,655 Re: Forum
187,549 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3