How many lights/watts can I put
on a 15 Amp service?
The rule of
thumb is to only load a breaker up to 80% of its
capacity. On a 15-amp service with 14/2 gauge wire one
should only load it up to 12 Amps MAX. Since most lights
will draw 1 amp per 100 watts a 15-amp breaker can
handle one 1K light each. This brings up another point
in home growing. That it is always good practice to have
the fans and the light that they cool on the same
breaker. That way if the breaker is somehow tripped
(Murphy's Law) then both the light and its cooling
system are down. Instead of the cooling system for the
light going down and the light still blazes away because
it was on another breaker.
Note: above figures
are estimated based on 110V supply.
Nietzsche recommends purchasing a CAT III meter
before doing any electrical work. It will allow for safe
testing of the circuit before commencing work. A clamp
meter is also handy for testing how many amps the
circuit is drawing without having to break the circuit
to do so, great to see if you get a peak when your
lights first come on or just how many amps a given
device is using.