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
International Wire Colour Codes
by Texas_Ranger
Today at 08:24 AM
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
230 or 345 kV transmission lines?
by annemarie1
10/12/16 01:23 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 11
HotLine1 6
renosteinke 6
ghost307 5
Potseal 4
Who's Online
1 registered (hyetal), 201 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#85462 - 07/07/03 01:28 PM Engineering Supervision
mountainman Offline

Registered: 01/29/02
Posts: 54
Loc: Richmond Va. U.S.A.
Article 310-15(b) of the 1996 NEC Engineering supervision, an engineer states that with his calculations he can use 4-4/0 conductors on a 4 wire wye circuit with a 225 ampere over currant protection. Would this override 310-15 Note #10(c). He has 4/0 copper in EMT in an electric room. And would you rquire the engineer to show his calculations? Thanks Joe

2014 / 2011 NEC & Related Books and Study Guides
#85463 - 07/07/03 02:10 PM Re: Engineering Supervision
Bjarney Offline

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
As the AHJ, an engineer has the responsibility to adequately demonstrate to you that the cable installation conforms to article 310. Paper calculations submitted to you containing a suitable explanation and his PE stamp may adequately support his position to your satisfaction.

[This message has been edited by Bjarney (edited 07-08-2003).]

#85464 - 07/07/03 03:50 PM Re: Engineering Supervision
George Offline

Registered: 02/23/02
Posts: 380
mountainman ---

If you are inspecting and is is not building according to the perscriptive code, you should ask for his calculations.

You need to have someone who can tell if the computations are correct or not.

#85465 - 07/07/03 06:12 PM Re: Engineering Supervision
Ron Offline

Registered: 03/13/02
Posts: 577
Loc: White Plains, NY
Absolutely have him/her show calculations and sign/seal them.
But, what am I missing? Table 310-16 shows 4/0 CU in the 75 degree column to have an ampacity of 230A. What is the issue with 225A CB serving a 230A conductor? Is it 100% rated breaker or something else? Maybe aluminum?

[This message has been edited by Ron (edited 07-07-2003).]


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