analysis 2011 IAEI

[M. D.]

Well , I know this article has been beaten to a pulp , but there is a good chance it will change again ,. the way this is worded has got me confused,.not hard to do,.. I would appreciate any clarity you folks might be able to provide.
Are they saying 215 gives permission for feeders to be sized by 310.15(B)(6) so long as they are not main power feeders ?,.. Good Grief
http://digital.ipcprintservices.com/display_article.php?id=205733

Revision: Table 310.15(B)(6) [now Table 310.15(B)

(7) ] Dwelling Unit Services and Feeders.

Table 310.15(B)(6) [now Table 310.15(B)(7)] has once again been revised by CMP-6. Using this section, main power feeders are no longer permitted to be sized by this table. Section 310.15(B)(7) covers only service conductors and service lateral conductors. However, Section 215. 2(A)(4) permits feeder conductors for individual dwelling units (or mobile homes) never to be required to be sized larger than service conductors. This section also permits Section 310.15(B)(6) [now Table 310.15(B) (7) ] to be used for feeder conductor sizing. Perhaps some well-worded comments are needed for the proposed change. Additionally, Table 310.15(B)(6) only applied to 120/240-volt, 3-wire, single-phase dwelling unit services and feeders. Th e 3-wire reference has been removed to allow for a feeder that may have 4-wire including the equipment grounding conductor.

 

[augie47]

It might be that it is "self evident", but I wish they would approach "sized larger than" to be worded as "not a greater ampacity than". One of the main arguments in this area on the 338.10(B)(4) situation is that a 4/0 feeder is the largest needed if there is a 4/0 service conductor (based on 215.2) without taking into account the ampacity of the particular conductors.
From what I've seen so far, I have considerable doubt that 2011 will rectify the confusion.