14/3 to attic

[Dennis Alwon]

i was looking in feeders ,min size in the 02 code.
i didn't think you could run less then 10"s to feed any sub.
at least thats what I've always done....

I believe you can add the panel legally. What is your concern?

 

[peter d]

i was looking in feeders ,min size in the 02 code.
i didn't think you could run less then 10"s to feed any sub.
at least thats what I've always done....

Well, it doesn't really matter what you've always done. The fact is, there is nothing in article 215 that forbids this 14/3 cable feeding a small subpanel and being subdivided into AFCI protected branch circuits, as long as it's within the calculated load.

You didn't say what article you were looking in, but I'm guessing it was 225. 225 does not apply to this situation.

 

[iwire]

i was looking in feeders ,min size in the 02 code.
i didn't think you could run less then 10"s to feed any sub.
at least thats what I've always done....

Can you tell us specifically the section number in the 02 that you are looking at? :smile:

 

[donselectric]

sure, it is 215.2a.
i dont think it's changed
in the 08 code, or has it ?

 

[peter d]

sure, it is 215.2a.

That code section says nothing about using minimum of #10 conductors to feed a subpanel. All it says that the feeder must be sized sufficiently to carry the calculated load. In this case, a 14/3 (2- 15 amp circuits) is likely plenty more than adequate for a few bedrooms.

 

[480sparky]

Can you tell us specifically the section number in the 02 that you are looking at? :smile:

225.39(B)

 

[iwire]

225.39(B)

Well I am pretty sure nothing Article 225 applies to this feeder unless this attic is missing a roof maybe. But even if it did the section you mention has no bearing on the conductor sizes.

 

[480sparky]

Well I am pretty sure nothing Article 225 applies to this feeder unless this attic is missing a roof maybe. But even if it did the section you mention has no bearing on the conductor sizes.

I just threw it out as a possibility.

OTOH, I do recall a #10 minimum size some years back. I just can't put my peepers on it right now because when I first noticed it, it wasn't in an obvious spot. I seem to recollect it was in Chapter 2 somewhere (except in 250).

 

[RJohnsonMasterElectrician]

Can't do it, I'm almost positive you have to have seperate neutrals to make trhe AFCI work

 

[Dennis Alwon]

Can't do it, I'm almost positive you have to have seperate neutrals to make trhe AFCI work

That has already been determined unless you can find a combo arc fault that is DP. I have heard they don't exist.

 

[M. D.]

Can't do it, I'm almost positive you have to have seperate neutrals to make trhe AFCI work

Can't do what??? Install a sub panel?? or use two single pole CAFCI breakers on a mutiwire ??

 

[RJohnsonMasterElectrician]

use a 14/3 on a afci. it would have to be a 14/4, but i was already corrected that this has been established.

 

[M. D.]

sure, it is 215.2a.
i dont think it's changed
in the 08 code, or has it ?

It changed ,...

Report on Proposals ? May 2004 NFPA 70

2-273 Log #832 NEC-P02
(215-2(A)(2) (3) (4))

Final Action: Accept in Principle in Part
Submitter: Dan Leaf Palmdale, CA

Recommendation:

Revise:
(2) For Specified Circuits. The ampacity of feeder conductors shall not be less than 30-amperes where the load supplied consists of the
following number and types of circuits;
(1) Two or more 2-wire branch circuits supplied by a 2-wire feeder
(2) More than two 2-wire branch circuits supplied by a 3-wire single-phase or direct-current feeder
(3) Two or more 3-wire branch circuits supplied by a 3-wire feeder
(4) Two or more 4-wire branch circuits supplied by a 3-phase 4-wire feeder.
(3) Ampacity RelativeTo Service-Entrance Conductors. The feeders ampacity shall not be less than that of the service-entrance
conductors where the feeder conductors carry the total load supplied by service-entrance conductors with an ampacity of 55 amperes or
less.
(3) (4) Individual Dwelling Unit, One-Family Dwelling, or Mobile Home Conductors. Feeder conductors for individual dwelling units,
one-family dwellings, or mobile homes need not have an ampacity be larger than service entrance conductors. Ungrounded feeder
conductors that supply a one-family dwelling shall have an ampacity not less than the minimum rating of the disconnecting means
specified in 225.39(C).
Exception: The additional feeders permitted in 225.30(A) shall have a minimum ampacity in accordance with 215.2(A)(2)
.

Substantiation:

More than two 3-wire branch circuits supplied by a 3-wire 3-phase in itself doesn't warrant a minimum 30-ampere rated feeder. For
example, a 3-wire 3-phase 240-volt feeder supplying three 2-wire single-phase circuits for three 1000 watt heaters would result in a
feeder current of 7.22 amperes with all loads energized and balanced. In my opinion, it is difficult and not necessary to provide for all
types and number of branch circuits which may warrant a minimum 30 ampere rated feeder. Three phase feeders may supply a variety of
single-phase and three-phase loads. Other Code rules adequately govern the minimum ampacity of feeders not specifically covered in
this section.


The requirements of (A)(3) are not justified on the basis of safety. Where a feeder complies with Code rules re: minimum size and
ampacity why should there be a required amapcity relationship? The rule doesn't apply where service conductors have an ampacity over
55 amperes. Is there a consideration for implied diversity or potential for future additional feeders for service conductors with an
ampacity over 55 amperes?

A feeder carrying the total load (20 amperes) supplied by service conductors rated 55 amperes is required to have an ampacity not less
than 55 amperes. If a future additional feeder is installed, its ampacity rating is determined by other Code rules, which should be the
determining rules for the original feeder.
The FPN for definition of Service-Entrance Conductors, Underground Systems, indicates there may be no service-entrance conductors.
Service-entrance conductors are included in 310.15(B)(6).
The present (4) should include feeders for one-family dwellings and relate to ampacity, not size. Aluminum feeder conductors may be
required to be larger than copper service conductors in raceway or cable, or individual open service-drop conductors.

Code-Making Panels 2 and 4 stated in the 2001 ROP and ROC that it is not necessary to establish a minimum rating for feeders
supplying a dwelling unit, which may be a unit of a multifamily dwelling but not necessarily a one-family dwelling; such dwelling units
already have a minimum feeder requirement in 215.2(2).
It is somewhat ludicrous to require a minimum 100 ampere rating for a one-family dwelling feeder disconnecting means in 225.39(C)
and not provide a similar minimum requirement for the feeder conductors supplying it, where in essence they are the "service".
Inconsistency does not enhance the Code.


Panel Meeting Action: Accept in Principle in Part


In the 2002 NEC text, take the following actions:
1) Delete 215.2(A)(2) - including items (1) through (4)
2) Renumber 215.2(A)(3) to be (A)(2) and revise "service-entrance conductors" to "service conductors".
3) Renumber 215.2(A)(4) to be (A)(3) and revise "service-entrance conductors" to "service conductors"
Reject the remainder of the proposal.

Panel Statement:

The panel agrees with the submitter that the limitations of the numbers of branch circuits supplied by a feeder are no longer warranted
because of the limitations placed on the circuit size by other rules. The panel does not agree that 215.2(A)(3) should be deleted. This
rule is consistent with the requirement of a minimum 8 AWG copper or 6 AWG aluminum in 230.31(B). The panel does not agree with
the submitter's revision of 215.2(A)(4), as the present rule is in place to resolve a specific 310.15(B)(6) issue raised with the conductors
for individual dewlling units and mobile homes.

Number Eligible to Vote: 13

Affirmative: 13 Ballot Results:

326

​

​

 

[slick 50]

FWIW I would use the 2 pole AFCI. Even if it's not combo type I think the end of 90.4 allows for just this type of exception to be made.

Great Idea, revert to previous code cycle if the product is unavailable at this time.

 

[slick 50]

If you do a load calc. I would be surprised if it required 2 circuits.


15 amp= 1800watt divided by 1.8 amp per receptacle is a total of 10 receptacles on the circuit. he needs to feed 12 plus recess lighting and fans. close call.

 

[480sparky]

If you do a load calc. I would be surprised if it required 2 circuits.


15 amp= 1800watt divided by 1.8 amp per receptacle is a total of 10 receptacles on the circuit. he needs to feed 12 plus recess lighting and fans. close call.

This is a dwelling. No limit on receps.

 

[LarryFine]

he needs to feed 12 plus recess lighting and fans.

If I was asked, I would recommend two circuits without hesitation. One for the receptacles, and one for the lighting and fans.

 

[iwire]

If I was asked, I would recommend two circuits without hesitation. One for the receptacles, and one for the lighting and fans.

Of course, we all know it's wrong to mix loads in a home.

What do you do when they plug lamps into your receptacle circuit?

 

[M. D.]

use a 14/3 on a afci. it would have to be a 14/4, but i was already corrected that this has been established.

You could always install a two circuit panel on the 14/3 and feed two combination type afci

And,... I always thought this was a 'beer tree':smile:

 

[LarryFine]

Of course, we all know it's wrong to mix loads in a home.

Absolutely. :wink:

Seriously (Hey, it could happen!), if you've gotta divide an area's supply into more than one circuit, why not do it that way?

What do you do when they plug lamps into your receptacle circuit?

Panic city!

Seriously (See? ), that's not an issue. I just understand that every ceiling light is usually turned on only during vacuuming.