ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Air Compressor feeder conductor sizing
by Potseal. 01/15/18 09:08 PM
VDE 0100 to introduce AFCIs
by LongRunner. 01/15/18 11:38 AM
Under carpet cable?
by HotLine1. 01/15/18 09:57 AM
Any New Years Resolutions?
by Bill Addiss. 01/13/18 10:21 AM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 25 guests, and 8 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
continuous loads #80828
05/30/02 03:34 PM
05/30/02 03:34 PM
E
Eandrew  Offline OP
Member
Joined: May 2002
Posts: 68
seattle, wa, usa
I'm confused over ampacity adjustments.

Table 310-16 is based on a continuous load without exceeding the insulation temp. rating -article 100

so why is the 80% corretion factor for a continuous load needed? Is this lower ampacity not built into table 310-16?

Is it necessary to lower the normal ampacity in 310-16 by 20% and then size the wire and overcurrent protection to 125% of that value. -Erik

2017 / 2014 NEC & Related Books and Study Guides
Re: continuous loads #80829
05/30/02 07:44 PM
05/30/02 07:44 PM
R
Roger  Offline
Member
Joined: May 2002
Posts: 1,716
N.C.
Eandrew, article 310-16 is correct. The conductors are rated at 100% and are not the issue in the 80% value. The 80% concerning continuos loads are for OCPD,s and the heat at the connection. If the OCPD is rated for 100% this will not be an issue. I assume by your use of the dash you are refering to the 99 code and if this is the case see 384-16d

Roger

Re: continuous loads #80830
05/31/02 01:36 AM
05/31/02 01:36 AM
E
Eandrew  Offline OP
Member
Joined: May 2002
Posts: 68
seattle, wa, usa
thanks rodger,

I was thinking that the 80% and 125% related to different things. It is clear to me now. Continuous loads are limited to 80% of the overcurrent device rating. A little algebra and you have an overcurrent device must be at 125% of the continuous load. got it, thanx.

Re: continuous loads #80831
05/31/02 05:16 PM
05/31/02 05:16 PM
R
Roger  Offline
Member
Joined: May 2002
Posts: 1,716
N.C.
You're welcome.

Roger


Featured:

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)
sparky 23
Admin 19
Potseal 13
Popular Topics(Views)
243,513 Are you busy
180,304 Re: Forum
170,802 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.077s Queries: 14 (0.014s) Memory: 0.9574 MB (Peak: 1.0903 MB) Zlib enabled. Server Time: 2018-01-16 19:20:04 UTC