ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Al Hildenbrand - Minneapolis - obituary
by bcpappas - 02/02/23 08:01 PM
Violation?
by renosteinke - 01/27/23 09:52 PM
Does NEC 551.71 (F) apply to dwellings?
by BigB - 01/20/23 10:46 AM
Power submeter connections
by HotLine1 - 01/19/23 09:09 AM
New in the Gallery:
Burger King crown sillyness
Burger King crown sillyness
by wa2ise, December 11
240/208 to a house
240/208 to a house
by wa2ise, October 9
Who's Online Now
0 members (), 12 guests, and 9 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#77202 05/10/01 08:01 PM
Joined: Oct 2000
Posts: 5,392
S
sparky Offline OP
Member
This is somewhat of a borrowed Q i thought i'd bring to this forum.

Taps are made , resulting in a conductors served from larger OCPD's, this is primarily addressed in 240-21
(b)feeders
(c)Xformers
(d)service cond.
(e)busway's
(f)motor circuits
(g)genny's

so how would the conductors included in
T310-15(b)(6) or T430-72(b) be defined in light of this?
( or are they meant as d & f ?)

any conjecture, speculation, etc...?
[Linked Image]




[This message has been edited by sparky (edited 05-10-2001).]

Stay up to Code with the Latest NEC:


2020 NEC & Related Reference & Study Guides
2020 NEC & Related Reference & Study Guides
Pass Your Exam the FIRST TIME with these Exam Prep Combos:
 

>> Master Electrician Exam Prep     >> JourneyMan Electrician Exam Prep
 

#77203 05/11/01 01:30 AM
Joined: Oct 2000
Posts: 2,722
Broom Pusher and
Member
Steve,

On the first table [if I am looking at the right one], I would say that the demand on free air feeders would be only high for minute times - not exceeding an hour or so.

On the other table T430-72 (b), I have some referenced notes that came with my 99 NEC, which edits the printed text.

In that note, there's a few points towards values of 400% of 310-17's 60 degree table, plus 300% of 310-16's 60 degree table.

I'm not exactly sure what level of current would cause a #10 cu to fry, but 160 amps would be at least close enough.

Is this going in the direction you were hoping?? [Linked Image]


Scott SET


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
#77204 05/11/01 05:14 AM
Joined: Oct 2000
Posts: 5,392
S
sparky Offline OP
Member
Thanks Scott!
yes, i find it interesting how the NEC defines protection in given situations. We tend to think in fixed numbers for conductors, yet this is frequently not so. The original Q eluded to just how far one can fanegal this in the NEC

Also the 'tap rules' as they are know, are not only to be smaller wires 'tapped' into larger wires, but also smaller wires directly introduced to larger OCPD's

This , although the end result is the same, creates a little focus on the definitional aspects of the practice.

The only guidance in those terms i have found is 240-3(e)

I just thought i'd throw it out for the BB's thoughts

[Linked Image]


Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *
2023 National Electrical Code (NEC)
2023 NEC Now Available!
 
* * * * * * *

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

 

Member Spotlight
mxslick
mxslick
Atomic City, ID USA
Posts: 806
Joined: October 2004
Top Posters(30 Days)
BigB 4
triple 3
Popular Topics(Views)
303,014 Are you busy
232,124 Re: Forum
216,776 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5