How Many Lights Can be on One Switch?

How Many Lights Can be on One Switch?

You probably want to have one switch that when you flick it, all the lights come on. You want to arrive home and have one switch light the living room and hallway. Is there a way to do this, to have on multiple lights being controlled by one switch?

The answer is yes; one switch can turn on multiple lights. You can use two ways to make your switch control multiple lights. The most common way is to daisy-chain the light fixtures through connecting them with each other and hooking the first fixture to the switch.

The second way to have all your lights controlled by one switch is through connecting them directly to the switch in a configuration referred to as “home run.” It’s easy to disconnect the fixtures you no longer need using the “home run” method.

In order to figure out how many lights can be controlled by one switch, there are a number of things you need to know.

The basics of light switch wiring

There is no limit to the number of lights on a circuit. The load of the fixtures is what determines how many lights a circuit can accommodate. A conventional 15A circuit can have up to 1400W of lighting loads connected to it. A 1400 Watts lighting load can accommodate one 1400W fixture or fourteen 100W fixtures.

Wiring

Before you go ahead and connect multiple cables to one switch, you need to know how to fix one cable. A typical 120-volt home circuit has two conducting wires and a ground. One of the conducting wires is black, and it’s the one that transfers the electricity from the power source to the load.

The other conducting wire is white. The white wire is the return wire that transfers the load back to the power source, completing the circuit. The terminals of a switch have only black wires as the switch interrupts the circuit’s hot leg. The terminals are brass.

The black wire from the power source is connected to one of the brass terminals known as the line terminal. You then connect another black wire that’s going heading to the light fixture, to the load terminal. With the black wires connected, you’re left with two white cables.

The white wires join the return path through which the load bypasses the switch. You join the white cables by twisting their exposed ends then screwing a wire cap on them. Before doing any wiring, make sure you turn off the circuit breaker to avoid electrocution. Also, before touching the wires, use a voltage tester.

Lighting fixtures

Daisy – Chain Light Fixtures

Daisy-chaining is different from wiring lights in a series. Lights wired in a series go out when one of them fails. In daisy-chaining, parallel wiring is used to fix light fixtures. Standard electrical color-coding is also used, making it easy to use the daisy-chaining method.

If what you are adding is a single installation, you need an extra cable that is compatible with your fixture. It is likely that you will run that wire through the attic. The only thing you’ll have to do is add the black cables to join the other two black wires and repeat the same process with the ground and white wires.

There may arise a need for larger wires caps since the number of cables in each set is increasing from two to three. The procedure of connecting another fixture to the one that you already added is similar to that of adding a single fixture the first time.

Now that you know the process of adding light fixtures to a switch, you can keep on adding more fixtures until you reach the break limit of the circuit’s current draw.

Home-run Lighting Fixture

The reasons for feeding wires from many light bulbs to one switch are mostly two. The first reason is convenience. You want the switch that is easiest to access to control multiple lights. The other reason is that the wiring is not permanent, and you want an easy way to disconnect the new light when the need arises.

When using the home-run light fixture to have one switch operate multiple lights, the outgoing hot cable is connected to the switch’s load terminal. The best way to make this connection is by using a pigtail.

The pigtail method means you use a 6-inch black spare wire to twist all the black wires together that are connected to the fixtures. Once you twist the black wires together, onto the split joint, screw a wire cap.

Use the same process to connect the ground cables to the ground terminals. As for the white wires, a pigtail is not necessary. The only thing you do is twist them altogether then cap them. The home-run wiring can become cumbersome when more than two lights are connected to a single switch. You may also need a bigger electrical box to hold all the cables.

Now that we have looked at the ways of wiring more than one light to a single switch, you are probably wondering, how many lights can be on one switch depending on the bulbs type of lighting used.

CFL bulbs v LED bulbs

Each LED or CFL bulb normally produces the same amount of light as a 60W incandescent bulb while the current it draws is 10 watts or less. Therefore, the current drawn is 1/12 amp. A 15-amp circuit can, therefore, control 180 or more LED or CFL bulbs.

Recessed light fixtures

Recessed lights provide a room with ambient light that is attractive. Recessed lights are fixed behind a ceiling, and in order for a room to be well lit, you need more than one fixture. The number of lights that one switch can accommodate depends on a number of factors.

These factors include the room shape and dimensions, canister width, and bulb wattage. The number of lights you can add on a circuit is also determined by the breaker rating.

Spacing of lights

Proper spacing of recessed light bulbs results in equal illumination of each part of the floor. Since each light bulb provides a cone of light, the ideal setting should allow the cones to overlap. For the light cones to overlap, a few factors need to be observed.

These factors include the height of the ceiling, bulb intensity, and diameter of the fixture’s opening. The general rule is that you can divide the ceiling’s height by two and use the number you get to space the light bulbs. For example, a room whose height is 8 feet, the standard spacing will be 4 feet.

The direction of light from recessed light bulbs

Improper use of recessed bulbs or overusing them results in the poor quality of the light they produce. When you line the lights in a row, a sightline pattern is created, and this effect isn’t appealing to the eyes.

The best pattern to place recessed light is an irregular pattern. Avoid spacing the lights too close to each other as you might end up with too much illumination. However, if the fixtures you are using are directional, you may need to space them in closer proximity compared to omnidirectional lights to get a good lighting effect in the room.

Breaker limitations

The main limitation on the number of recessed lights that a single switch can control is the rating of the circuit breaker controlling the circuit. Each incandescent or halogen 60-watt bulb draws around 1/2 amp, and therefore, standard lighting with a 15amp breaker can manage 30 lights.

When it comes to LED and CFL bulbs used in recessed fixtures, we have mentioned that they produce light that is similar to a 60W incandescent bulb. The inrush current for LED lights is usually 20 amps for 240VAC. Therefore, a 15amp circuit can safely accommodate 180 or more fixtures using LED or CFL bulbs.

What we view as “normal bulbs” are usually 60W incandescent bulbs. A circuit with a currency of 120 volts and 15ampere provides 1800 watts. This means that the 15ampere switch can accommodate a maximum of 30 incandescent bulbs.

The way we have reached the number of bulbs is easy.

  • Take 120 volts * 15 amperes = 1800 watts.
  • 1800 watts / 60 watts = 30 bulbs. (The total watts divided by the watts in a single bulb)

We have seen that the number of lights that one switch can accommodate can be anything from 1 to 180. The factors that will determine how many lights can be flicked on and off by one switch include breaker limitations of the circuit and the number of voltages a single switch can accommodate.

Conclusion

The question of how many lights can be on one switch can also be answered by looking at the type of bulb you plan on using. The number of incandescent lights that a single switch can control is different compared to the number of LED or CFL bulbs.

The way you do your wiring of the extra lights determines how many additional lights a single switch will control.

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