On Aug 30, 6:46*pm, bud-- wrote:
RBM wrote:
"bud--" wrote in message
. ..
RBM wrote:
"Salmon Egg" wrote in message
...
In article m,
David Nebenzahl wrote:

On 8/29/2009 8:09 AM John Gilmer spake thus:

I mentioned that to the electrician (licensed, experiences, etc) and
he basically said that 15 amp "light" switches can be properly used
on a 20 amp circuit.
Where did he get that idea?

That one doesn't even pass the common-sense test. If a device is rated
for 15 amps, how is it OK to use it on a circuit drawing (potentially)
20 amps?

Now, I could see using a 15 amp switch on a 15-amp circuit (meaning one
connected to a 15 amp breaker) but wired with #12 wire. Is that what
the
electrician meant?
I am not a real expert on the subject but I do not see the problem. Very
few lights would even come close to requiring 15 A. A fixture containing
three 100 watt lamps requires less than three A on a 120 V power line
(neglecting inrush current). You can always screw things up by placing
an overload exceeding 20 *even if had 20 A switches.

Electrical codes can be arbitrary, but I would be surprised if all parts
of a circuit must always be matched to each other.

Bill

--
Private Profit; Public Poop! Avoid collateral windfall!

We have a winner!! * You can't put a single 15 amp outlet on a 20 amp
circuit, because the potential to overload it, and by the same logic, you
wouldn't put a 10 amp or 15 amp switch on a load greater than the switch
capacity, but you certainly can install a 15 amp switch on a bank of
lights that draws 10 amps, which is fed off of a 20 amp circuit.

I agree.

The NEC requires "switches shall be used within their ratings".

IMHO a 15A switch on 20A circuit with 20A or multiple 15A receptacles
would be a violation.

--
bud--

This is one of the many NEC rules that make no sense to me. The same thing
with multiple disconnects on a service, the original installer may have
calculated the load, but who knows about any subsequent installations and
installers

The way I read the thread I was agreeing with you. A 20A circuit with a
10A switch for a lighting fixture is OK because it is substantially
impossible to put over 1200W of lights in. Switching an outlet is more
of a problem.

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."
--
Tom Horne


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.