It is simple. Just add up how much amperage you are going to load on the circuit-the amp rating is on each one of the lights. My 1000 watt light use about 8-9 amps each. Make sure you do not overload the circuit. You can easily run two on a 30amp circuit, which will still leave room for a pump or air pump. The in line fans use about 2-3 amps depending on size. You can easily add 1 with the lights. Just make sure that the circuit is not overloaded, that is the key. When large pumps, such as shaft drives come on, we are talking a 10 amp motor, for instance, you will have FLA or full load amperage-it can peak as much as 12-15 amps when running perfect. Have a motor on its last leg, and it could pull high amps before dying as much as 15-20 amps before it croaks. If you have loaded the circuit within 3 amps(lets say 27 amps on a 30 amp circuit) then you run the risk of tripping the circuit. Just make sure you add up all amps being used on each circuit, and once again, don't overload it. You don't want to be gone for a day and find your garden in the dark 1/2 way thru the light cycle. Hope this helps.
