0 item(s) - $0.00
You have no items in your shopping cart.

How many lights can I run on a circuit?

It's important to never overload your electrical circuits, as they can overheat and create a fire hazard, or trip a circuit breaker and stop important equipment in your grow. To ensure you're being safe, you need to check what is plugged in already, and how much the circuit can handle. If you have any questions or doubts about your electrical setup, it is always best to consult a local electrician!

What kind of circuit?

Standard North American electrical circuits have different shapes for different circuit types, with outlets that looks like this:

NEMA 5-15
110-120 volt, 15 amp
(NEMA 5-15)
NEMA 5-20
110-120 volt, 20 amp
(NEMA 5-20)
NEMA 6-15

220-240 volt, 15 amp
(NEMA 6-15)
NEMA 6-20

220-240 volt, 20 amp
(NEMA 6-20)


  • Our PhytoMAX-2 LED grow lights come with an 8 foot power cord for 110-120 volt outlets (NEMA 5-15, compatible with NEMA 5-20); we have various length heavy duty power cords available for purchase as well.
  • We also offer North American standard 220-240 volt cords (NEMA 6-15, compatible with NEMA 6-20) for purchase here.
  • Outside North America? All you need to run our PhytoMAX-2 lights is an IEC C13 (female) power cord of the right gauge that will work with your wall outlets, as long as you're between 100 and 277 volts. These are fairly standard computer and ballast cords and should be easy to find locally at a hydroponic shop, office supply or appliance store.
    IEC C13 plug

What's on my circuit?

To determine what's on a circuit, you can turn off the breaker in the electrical panel and count all the electrical outlets (and things plugged into them) that stop working. Keep in mind they may not all be in one room!

What can I safely plug in?

Circuits are rated for different loads based on their amperage capacity. More amperage requires thicker wires to handle the extra flow of electricity. It is unsafe to rely on more than 80% of the capacity of any circuit; the wires may get hot or the breaker may trip. Some appliances such as fans, pumps and lights (including our LED grow lights) may require a bit more than their average electrical draw when they start up.

To ensure you're being safe plugging in your LED grow light, add up the wattage of everything you want to run on an LED light circuit. Divide the total wattage by the circuit voltage to get the number of amps, and make sure this is less than 80% of the circuit's rated capacity!

For example, consider one our 5'x5' led grow light tent kits with a PhytoMAX-2 800, a 6" Max-Fan, and a 50-watt oscillating fan, all plugged into one circuit.

Electrical Appliance Watts
PhytoMAX-2 800 840
6" Max-Fan 84
Oscillating fan 50
Total 974


This circuit would have a total of 974 watts running on it. For a 110 volt circuit, that is ( 974 / 110 ) = 8.9 amps, which is safe to run on a 15 amp circuit (80% of 15 = 12 amps safely usable).

Adding a PhytoMAX-2 400 to the same circuit would result in:

Electrical Appliance Watts
PhytoMAX-2 800 840
PhytoMAX-2 400 420
6" Max-Fan 84
Oscillating fan 50
Total 1394


This circuit would have a total of 1394 watts running on it. For a 110 volt circuit, that is ( 1394 / 110 ) = 12.7 amps, which is unsafe to run on a 15 amp circuit (80% of 15 = 12 amps safely usable).

2 thoughts on “How many lights can I run on a circuit?”

  • Payette

    I want to Plug 5 times PhytoMax-2 400 on 2 different circuits of 15 A 120 V It it possible ? with all the fans etc ... ?

    thx a lot


    • Kevin

      Hello Mark,

      You can safely put 3 of our PhytoMAX-2 400 lights on a 15A, 120V circuit. Since you have 2 circuits, you could put 3 lights on one, and 2 lights on the other with the ability to have up to 500 watts of fans or other equipment on that 2-light circuit.

Leave a Reply