Tom Horne wrote:
On Aug 30, 6:46 pm, bud-- wrote:

Multiple service disconnects could certainly be a problem - they are a
lot safer if non-electricians leave them alone. IMHO most of the
potential problems are "split-bus" panels in a house. My reading of the
code is they are still allowed but I don't know if anyone even makes
them anymore.

--
bud--

Bud
They are effectively forbidden by the requirement that "Each lighting
and appliance branch-circuit panelboard shall be individually
protected on the supply side by not more than two main circuit
breakers or two sets of fuses having a combined rating not greater
than that of the panelboard."

Wayne is right that "lighting and appliance panelboards" disappeared in
the 2008 NEC. You are quoting a NEC version before 2005 (but 2005
probably said the same thing, relocated).

The 2008 NEC also has the same requirements, I believe, as what you
quoted, with the 42 pole limit moved into the main article text, which
is 408.36 exception 2.

My reading is that you can have a split bus panel, but that there can
only be 2 main circuit breakers (instead of the previous 6). (One
breaker feeds the split bus in the rest of the panel and the 2nd breaker
can feed your flying saucer port on the roof.) The sum of the main
breaker ratings has to be not greater than the panelboard rating, but
there is nothing in this article that I see that prevents the 2 devices
from having a rating larger than the service wires using the 6
disconnect rule.

IMHO this is one of the articles where it would help to be a lawyer. (Or
maybe not.) You might have used a different lawyer?

--
bud--



408.14 Classification of Panelboards.
Panelboards shall be classified for the purposes of this article as
either lighting and appliance branch-circuit panelboards or power
panelboards, based on their content. A lighting and appliance branch
circuit is a branch circuit that has a connection to the neutral of
the panelboard and that has overcurrent protection of 30 amperes or
less in one or more conductors.
(A) Lighting and Appliance Branch-Circuit Panelboard. A lighting and
appliance branch-circuit panelboard is one having more than 10 percent
of its overcurrent devices protecting lighting and appliance branch
circuits.
(B) Power Panelboard. A power panelboard is one having 10 percent or
fewer of its overcurrent devices protecting lighting and appliance
branch circuits.

408.16 Overcurrent Protection.
(A) Lighting and Appliance Branch-Circuit Panelboard Individually
Protected. Each lighting and appliance branch-circuit panelboard shall
be individually protected on the supply side by not more than two main
circuit breakers or two sets of fuses having a combined rating not
greater than that of the panelboard.
Exception No. 1: Individual protection for a lighting and appliance
panelboard shall not be required if the panelboard feeder has
overcurrent protection not greater than the rating of the panelboard.