"Tony Hwang" wrote in message
news:Wl3nb.194451$9l5.193936@pd7tw2no...


Tom Horne wrote:
Hello,
I'm adding some recessed lighting in my basement. The wiring that is
there
consists of some 14/2 wire and 12/2 wire for the existing recessed
lights.
There are 4 of them right now. I was wanting to add 6 more on one 15
amp
circuit. The bulb themselves would be 65 watt spots. Will one 15 amp
circuit
handle 6 lights? Can I get away with using 14/2 NM wire or should I
use the
heavier 12/2 on the new circuit? When all is done I would have 2 -15
amp
circuits that have 6 recessed lights each. Is this safe?

Thanks in advance,
Joseph
Indiana


A fifteen ampere circuit will carry a continuous load such as lighting
of 1440 volt / amperes. A twenty ampere circuit will carry 1920. Do
the math. Divide the circuits available VA capacity by the VA of the
installed lamps and you will get the number of lamps that the circuit
will carry. As long as the lamps are incandescent the wattage of the
lamps can be used as the VA of the lamps.
--
Tom

Hi,
VA is not equal to Watts. Reason? Power factor, Cosine Phi.
As far as math is concerned.
Tony

Probably why Tom Horne specifically stated "as long as the lamps are
incandescent..." For calculating purposes, the PF of a resistive load
(such as an incandescent light) is PF = 1, thus VA = Watts, for a resistive
load. If an inductive load is served (such as fluorescent light fixtures),
_then_ the PF must be considered, in which case, to calculate VA one must
use the amp draw printed on the fluorescent light _ballast_ label, _not_
the amp draw as "calculated" from the wattage of the fluorescent lamp(s).