ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Where is Everyone?
by gfretwell - 04/09/21 01:08 AM
HI gang, long time since I was here...
by gfretwell - 04/09/21 01:02 AM
Lock-down Thread
by gfretwell - 04/06/21 09:30 PM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 13 guests, and 18 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
derating rooftop conductors #214531 12/18/14 11:28 PM
Joined: Mar 2004
Posts: 782
B
BigB Offline OP
Member
When derating THWN-2 copper conductors for ambient that will eventually terminate in a sub panel with a 125 amp rating can I use the 90C column?

2017 / 2014 NEC & Related Books and Study Guides
Re: derating rooftop conductors [Re: BigB] #214533 12/19/14 04:54 AM
Joined: Jun 2004
Posts: 1,273
T
Tesla Offline
Member
The sole and only reason for that column IS derating.

For there are no 90 degree rated devices out there.

One then uses the lesser computed ampacity limit.

So, yes, you start with the 90 degree column.


Tesla

Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Trumpy
Trumpy
SI,New Zealand
Posts: 8,379
Joined: July 2002
Show All Member Profiles 
Top Posters(30 Days)
BigB 1
Popular Topics(Views)
277,594 Are you busy
211,257 Re: Forum
198,280 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3