Bill writes:
Scott Lurndal wrote:

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Section 410-31 of the NEC (1999 Edition) states:

Fixtures shall not be used as a raceway for circuit conductors.

Exception #1: Fixtures listed for use as a raceway
Exception #2: Fixtures designed for end-to-end assembly to
form a continuous raceway or fixtures connected
together by recognized wiring methods shall be permitted
to carry through conductors of a 2-wire or multiwire
branch circuit supplying the fixtures.
Exception #3: One additional 2-wire branch circuit separately supplying
one or more of the connected fixtures described in exception
#2 shall be permitted to be carried through the fixtures.

Branch-circuit conductors within 3 inches of a ballast within the ballast
compartment shall have an insulation temperature rating not lower than
90 degrees C such as Types RHH, THW, THHN, THHW, FEP, FEPB, SA and XHHW.

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Most consumer grade flourescents aren't listed as raceways. That pretty
much leaves exception #2 as the guidance for this application. It also limits
you to 2 two-wire or 1 three-wire and 1 two-wire branch circuits for the
string of fixtures.


Scott.

There is only 1 15A branch circuit. However, I had planned for it to
"split" through 3 switches in the switchbox and pass the resultant 5
wires--3 hot, 1 neutral, 1 ground, through the fixtures as necessary to
power them. If I understand correctly, this would qualify as a single
2-wire branch circuit, wouldn't it?

Yes. The extra wires in this case do not matter[*], since they'll sum to the
maximum branch circuit current (15a, in this case). This is would not be
considered a multiwire branch circuit, however, per article 100 and 210-4, which
requires a potential difference between the ungrounded conductors.

In other words, you have multiple paths for the same branch circuit.

scott
[*] subject to raceway fill guidlines.