How Many LED Lights Can I Put On One Circuit?

While LEDs are generally low wattage, that doesn’t mean you can install as many as you want in your home without risk.

Every electrical circuit has its limits, and if you exceed those limits, you’ll blow the circuit breaker, cutting all power to the circuit. It can also be dangerous, as blowing a circuit breaker can damage the circuit.

So how do you know the limits of the circuit?

The limit of LED lights on one circuit depends on the wattage of the lights in question. Divide the sum wattage of the lights by the voltage to give you the amperage, and as long as that amperage of lights is no more than 80% of the circuit’s rated amperage, it is safe.

In this guide, I’ll explain in more detail:

• How you can calculate the maximum number of lights on any circuit
• The maximum number of LEDs on a 15 amp circuit
• How many LEDs a light switch can handle

How To Calculate The Maximum Number Of Lights Per Circuit

When it comes to calculating the maximum number of lights on any electrical circuit, there are three things you need to know – the wattage of the lights that you’re using, the voltage of the circuit, and the amperage of the circuit.

The voltage depends on the power source.

If we’re talking about a battery-powered circuit, then it depends on the power of the battery – it might be 9 volts, or 12 volts, although some other battery sizes are possible too.

When we’re talking about electrical circuits at home, in the US, the voltage is 120 volts as standard, while in the UK and Europe, it is 230 volts.

The amperage of the circuit will be defined by the circuit breaker (fuse) in place.

And then, with your lights, you need to check the individual wattage of each light and add them together to get the sum wattage you want to add to the circuit.

When you have all this info, you can determine how many lights you can place on the circuit.

Here’s what you do:

• Multiply the amperage of the circuit by the voltage
• Multiply this by 0.8 to give you 80% of the maximum capacity
• This is your maximum wattage, so divide this figure by the wattage of your lights to find out how many you can use on the circuit.

The problem with this is that you’re relying on the bulbs all being the same wattage, which they might not be. You might be using a mix of bulbs.

If so, you must work it out in reverse instead. Add the wattage of the bulbs you want to use on the circuit and check that it doesn’t exceed 80% of the circuit’s maximum capacity.

Why 80%?

The reason for this recommendation is that electrical items aren’t always consistent. They broadly are, but you might get a power surge or spike, especially when first turning items on.

This means the electrical items in question could be drawing more wattage than they say, even if it’s only for milliseconds.

And yet, any time the maximum amperage is exceeded on the circuit, the breaker will trip.

Giving yourself 20% of unused capacity ensures you don’t blow the breaker unnecessarily, even with those spikes.

How Many LED Lights Can Be On A 15 Amp Circuit?

Now that we know how to calculate the maximum number of lights on any circuit let’s get specific and examine how many LED bulbs work on a standard home lighting circuit.

In most homes, a lighting circuit is 15 amps. Other electrical circuits may be rated higher, but circuits explicitly designed for lights are usually limited to 15 amps.

So with that in mind, we know that the maximum wattage capacity of a lighting circuit in the US is 1,440 watts.

That’s because:

• 15 amps x 120 volt US circuit = 1,800
• 1,800 x 0.8 = 1,440

We know the maximum wattage, but how many LEDs does that translate to?

Before we get into that, there’s a crucial point to clarify with LED lights. LED lights only require a little power compared to older light bulbs such as halogen or almost-obsolete incandescent bulbs.

But for many years, the ‘brightness’ of light bulbs has been advertised using the wattage, even though the wattage and the lumens of a bulb don’t directly correlate.

What this means is that LED lights are often sold with the description of being “X watts equivalent,” e.g., “60-watt equivalent” or “40-watt equivalent”, because they’re a similar brightness to what an older 60-watt or 40-watt bulb would have been.

But this figure is useless for working out how many LEDs can be used on a circuit. You need the actual wattage, which will be much lower, typically 4 to 12 watts.

Let’s use a 10 watts LED bulb that is 60-watt equivalent. This makes the sum really easy since it’s capacity of 1,440 watts divided by 10 – you can have 144 LED bulbs on the circuit.

Sounds like a lot, right?

Remember that home electrical circuits were designed for the higher-wattage bulbs we used to use. We can add more LEDs to the same circuit since they use a fraction of the power.

However, there is one more consideration…

How Many LED Lights Can One Switch Handle?

While the power rating of the circuit is essential, you also need to bear in mind your light switches.

Not so much with regular light switches – these aren’t impacted by the number of bulbs on the switch. It matters with dimmer switches, though.

Dimmer switches work in different ways – traditional dimmers reduce the circuit’s current to drop the power, but they aren’t compatible with LED lights for that reason. So you need a special LED dimmer switch if you want to dim LED bulbs (as well as use dimmable bulbs too).

And these LED dimmer switches will have a maximum wattage rating that you can’t exceed.

To be clear, think of your home lighting circuit as one massive loop with several off-shoot loops for each room.

If you add a dimmer switch to a room, the maximum wattage is for that room alone – not the entire home. So you’re only concerned with the wattage of the bulbs that the switch will control.

Common LED dimmer switches will be rated for 150 watts of LED lights, though make sure to read the box or description carefully, as they may have separate ratings for LEDs and older lights.

You might think 150 watts sound like a lot for a single room if LED bulbs average between 4 and 12 watts.

But if you’re using a chandelier or other fixtures with multiple bulbs, you need to check to ensure you are within the limit.

Final Words

In most cases, you won’t have trouble adding LED bulbs to your electrical circuits. Especially at home – having 1,440 watts to play with on a standard US 15 amp circuit is more than enough in most cases.

But if you have a lot of multi-bulb fixtures or a large home, you should be careful, especially if you’re also using dimmer switches.

Exceeding the limits can blow out the breakers and cause damage to circuits, which could even become a fire hazard if you allow the problem to recur.

Have you switched to LEDs in your home and had any issues with the circuit breaker tripping?