The number of LED lights that can be installed on a 20-amp circuit depends on the wattage of the lights and the total wattage capacity of the circuit.
On a 120V supply, a 20 Amp lighting circuit has a maximum wattage capacity of 2400W, with a total combined wattage of LED to not exceed that. We look at how many LED lights can be on a 20 Amp circuit to avoid issues such as flickering, dimming or even tripping of the circuit breaker due to an overload.
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When calculating how many LED lights can be on a 20 amp circuit breaker, there are two simple calculations to make; find the total capacity of the circuit and then how many lights sources will reliably run on it.
To determine the total wattage of lights that can be accommodated, use the formula:
watts = volts x amps
To calculate how many watts on a 20 amp circuit breaker, multiply the voltage of your lighting circuit (which is the USA is 120 volts) by the amperage of your lighting circuit, which in this case is 20.
120V*20A = 2400 Watts
Best practice electrical installations design maximum capacities of lighting circuits to use 80% of it’s potential. 80% of 2400 watts is 1920 watts total capacity.
Then to estimate how many LED lights can be safely installed on a 20 Amp circuit, check the wattage of your LED products or bulbs and use the formula:
Number of LED lights = Maximum circuit wattage / LED Watts rating
All LED lights consume energy at a reduced rate compared to other technologies. Check the product or bulb to see what it’s wattage is. A 40W incandescent bulb equivalent in an LED bulb is often rated at 5.5W
1920W/5.5W = 349
Therefore, a 120V 20A circuit can accommodate up to 348 5.5W LED light bulbs.
The number of lights that can be installed on a 20-amp circuit depends on the wattage of the lights and the total wattage capacity of the circuit.
When using various types of LED light sources and other technologies such as fluorescent, halogen and incandescent, there will be mixed wattages to consider.
Combine each light fixture’s power consumption by adding up the wattages and do not go over 1920 watts, which if you are using LED will give you the option for a lot of lighting.
Electrical derating is essential to prevent circuits from being overloaded, but certain LED light fixtures may cause a momentary surge of current that can exceed the circuit breaker’s capacity and trigger it to trip.
To compensate for this, the total loading of the circuit has to be further derated according to each manufacturer’s recommendations. This is not usually applicable to most LED bulbs.
Using a 80% derating on a 120V circuit, no more than 38 lights should be used.
No more than 19 lights should be used using the recommended 80% derating on a 120V circuit.
Using a 80% derating on a 120V circuit, a maximum of 240 bulbs can be used.
The wattage of a 20 amp 240V circuit is 4800 watts.
To calculate multiply the voltage of your lighting circuit (which is the EU, UK & Australia is 240 volts) by the amperage of your lighting circuit, which in this case is 20.
240V x 15A = 4800 Watts
We also look at How Many Light Can Be On a 15 amp circuit.
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