How do you know how many fixtures (how much LED load) to put on one Controller?

Each controller can carry up to 15 Amps at 120 or 277 Volts.

Example #1

We have 100 SWISH 2X4’ fixtures rated at 49 Watts per fixture. What is the maximum number of fixtures we can put on one controller at 120 Volts?

Calculate Controller switching capacity in Watts (Amperage x Voltage = Wattage):

15A x 120V = 1,800 Watts; 1,800/49 = 36.73, or 36 fixtures per Controller.

Example #2

We have 75 RAIL fixtures rated at 225 Watts per fixture at 277V. What is the maximum number of fixtures we can put on one controller at 277 Volts?

Calculate Controller switching capacity in Watts (Amperage x Voltage = Wattage):

15A x 277V = 4,155 Watts; 4,155/225 = 18.46, or 18 fixtures per Controller.