The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!


2017 NEC and Related
2017 NEC
Now Available!

Recent Posts
Parking lot pole light swap....
by gfretwell
10/24/16 08:46 PM
International Wire Colour Codes
by Tjia1981
10/23/16 12:08 PM
Son of Sparky
by HotLine1
10/20/16 07:43 PM
Speaking of Plugmold ...
by gfretwell
10/17/16 02:37 PM
Broken battery charger? Check for cobwebs!
by gfretwell
10/17/16 02:30 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 14
HotLine1 7
ghost307 7
renosteinke 6
Potseal 4
Who's Online
0 registered (), 260 Guests and 5 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#91852 - 02/09/05 08:20 AM 4160 volt conductor rateings
Yoopersup Offline

Registered: 03/04/03
Posts: 826
Loc: Michigan
Table 310.73 2001-5000 volts M.V.105.
500kcmil =530 amps for derateing 475 for terms(110.40). As i see it no derateing for a bank of pipes in open air. Thus 2000 amp requirement = 4 sets 530x4=2120
or 4 sets 475= 1900 amps.
240.101 states fuse can be 3 times conductors ampacity breaker or electronically actuated fuse up to 6 times.

So as I see it conductors must be rated for the ampacity of the true load. Over current protection can be higher then conductor rateings.
The highter amps rateing 105% for derateing only the 90% rateing for terms.
so if load is 1900 amps or below 500s can be used ,fused at 2000 amps.

2014 / 2011 NEC & Related Books and Study Guides
#91853 - 02/10/05 10:28 AM Re: 4160 volt conductor rateings
Bob Offline

Registered: 02/05/02
Posts: 182
Loc: Mobile, AL, USA
What is the load your are working with?

#91854 - 02/11/05 04:58 AM Re: 4160 volt conductor rateings
Yoopersup Offline

Registered: 03/04/03
Posts: 826
Loc: Michigan
Last sentence says 1900 amps or below.


ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals