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#87676 04/08/04 04:22 PM
Joined: Feb 2002
Posts: 840
C
Member
Does table 310.15 B6 allow #2 Aluminum SER cable to be protected by a 100 amp breaker to feed a subpanel? (common practice around here)
By "subpanel", I mean a panel that is fed from the panel that contains the main disconnect.

I can't figure out if this table only applies to feeders between the main disconnect(s) and panelboard(s), or all feeders in a dwelling.

Feeder: "All circuit conductors between the service equipment....and the final branch circuit overcurrent device." (NFPA 70, 2002 Article 100 definition)

[Linked Image]

Peter


Peter
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#87677 04/08/04 04:31 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Peter I will say yes to your question, but wait for other replies as this one confuses me too and I do not use this table at my work.

I base my answer on this part of 310.15(B)(6)

Quote
For application of this section, the main power feeder shall be the feeder(s) between the main disconnect and the lighting and appliance branch-circuit panelboard(s).

Notice the (s) on feeder and panelboard.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#87678 04/08/04 05:49 PM
Joined: Aug 2003
Posts: 1,374
R
Moderator
In my opinion, you are correct (as is Bob).

I, like Bob, think the "main power feeder" must originate at the service equipment and end at a lighting and appliance panel. If you had a 200 amp panel (outside service equipment), it would be legal to feed an indoor panel with 4/0 AL, but it would be a violation to leave the interior panel and feed another panel with 2 AWG (unless the terminals were rated 75 degrees and you use the round-up rule). Once you have a feeder that originates outside of the service equipment, you are in the land of 310.16, not 310.15(B)(6).


Ryan Jackson,
Salt Lake City
#87679 04/08/04 06:03 PM
Joined: May 2002
Posts: 1,716
R
Member
Anything; be it a device, appliance, down stream panel, etc... fed from the lighting and appliance branch-circuit panelboard(s), will fall under "other" articles, and can not use 310.15(B)(6).

Here we go. [Linked Image] [Linked Image]

Roger

#87680 04/08/04 06:11 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
I say just remove Table 310.15(B)(6) and have us all use 310.16. [Linked Image] [Linked Image]

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#87681 04/08/04 06:13 PM
Joined: Aug 2003
Posts: 1,374
R
Moderator
I vote Bob for president


Ryan Jackson,
Salt Lake City
#87682 04/08/04 06:14 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
You can not round up 90 amp rated 2 AWG AL to 100 amps as 90 amps is a standard size OCPD.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#87683 04/08/04 06:15 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Now I feel bad for my last post.:O

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#87684 04/08/04 06:19 PM
Joined: May 2002
Posts: 1,716
R
Member
Bob,
Quote
Now I feel bad for my last post.:O
the truth hurts. [Linked Image] I'm sure Ryan will still vote for you (maybe [Linked Image]), I know if you get 310.15(B)(6) removed (or my preference, have it reworded) I will. [Linked Image]

Roger



[This message has been edited by Roger (edited 04-08-2004).]

#87685 04/08/04 06:28 PM
Joined: Aug 2003
Posts: 1,374
R
Moderator
Quote
You can not round up 90 amp rated 2 AWG AL to 100 amps as 90 amps is a standard size OCPD.

I didn't even look at 240.6, just assuming that 90 is an off the wall number and wouldn't be considered standard. One of these days I'm gonna stop shooting from the lip and start looking in the code before I post :0


Ryan Jackson,
Salt Lake City
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