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Have you ever wondered how many lights you can connect to one light switch? It could be useful to have multiple lights connected to one switch in your kitchen and dining areas where numerous light fixtures are required to create the necessary ambiance. But just how many light fixtures can you connect to one switch?
The number of light fixtures that you can put on a light switch is dependent on the power the fixtures draw and the wire gauge. Some light fixtures, such as lamps and ceiling fan lights, use multiple bulbs and draw more power. Most circuits in a home allow for 15 to 20 amps, so you can safely connect 1400 to 2400 watts of lighting on one light switch. That’s enough for 23 to 40 60-watt bulbs or 280 to 480 5-watt LEDs.
Having multiple lights on a single switch would be an excellent feature for special events or the areas in your home that need more than one light. In this article, you’ll find out how many light fixtures you can put on one switch, as well as how to connect multiple lights to one source. Safety should always be the primary concern when working on anything with electricity within the home. It is recommended to always get a professional to do any work with electricity.
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How Many Lights to Put on One Switch
Before connecting several light fixtures to a single light switch, it is important to know the amount of power (watts) the light bulbs use, the circuit amps, and whether the cable can carry the current or electricity supply successfully (source).
Breaker Switch and Wall Switch Ratings
A 15-amp circuit typically requires at least 14-gauge wire, while a 20-amp circuit requires 12-gauge wire running to your breaker box. You also need to ensure that your wall switch has the proper current and voltage ratings. Some 15-amp wall switches are only rated for 120 volts.
A 15-amp switch can support 1400 watts, while a 20-amp switch can support up to 2400 watts. If you had a fixture that used 2 60-watt bulbs, you could support 11 of those fixtures on one 15-amp circuit or 20 of the same fixture on a 20-amp circuit.
Series Circuits and Fuses
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Some series circuit lights, like Christmas tree lights, use fuses. If the current flowing through the wire is too high for the cable that the lights are feeding from, then the bulbs will blow.
Fuses act as a weak point in the circuit that will give if the connection becomes too hot. The fuse prevents fires from occurring or the light bulbs from exploding if the cable overheats.
To determine how many lights you can direct to one switch, you first need to know how many watts each lightbulb requires. Then, you can determine which fuses to apply and which size cables and wires to use that will prevent both the fuses and wires from overheating.
A 240-voltage supply serves most homes, and most circuits are either 220-volt or 120-volt, so you will need to divide the number of watts of all of the lightbulbs combined by the amount of voltage supplied to the circuit.
Watts Divided by Supply Voltage Equals Fuse Amps
For example, if each of your lightbulbs uses 60 watts (0.06 kilowatts), you would then need to adjust the wires and fuse that accordingly. The resulting formula would be 60 watts divided by a voltage of 240, which equals a 0.25 amp requirement for the fuse in the plug or light switch.
Christmas tree lights, typically with numerous 5-watt bulbs, often come with 5-amp fuses, which could support 240 bulbs on 240 volts of supply.
Fuse Amps Multiplied by Supply Voltage Equals Bulb Wattage
You can also do this calculation the other way around. If you already know the amps of the fuse that you have on hand, you can then multiply the voltage by the amps. This will give you the maximum number of watts that you can connect to the circuit.
For example, if a typical 5-amp fuse protects your light circuit, you can multiply this by the voltage (240) to get 1200 watts worth of light bulbs that you can connect to the circuit with that fuse.
To learn more about how to safely wire lights in series, and whether it is recommended, take a look at “Can I Wire Lights in Series?”
How to Connect Multiple Lights To One Switch
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Your project might involve multiple lights in a large kitchen or dining area, or you might want to set up a series of lights in your shop. How do you wire these light fixtures to a single switch?
There are two main ways to wire multiple lights to a single switch, and electrical engineers refer to these as “daisy-chaining” and “home run” switch wiring (source).
Daisy-Chaining Fixtures
Instead of wiring lights in a series, like the Christmas tree light example, daisy-chain wiring involves parallel wiring. Daisy-chaining allows the other lights to function when one of them goes out.
Just remember you color-coding: white is neutral, black is hot, and the bare wire is ground.
Daisy-chaining requires a separate cable to run between each fixture, and you may need larger caps for your wires since the connections now involve three instead of two wires — those connecting the load and fixture to one another and the wiring leading to the other fixture.
You can add as many fixtures you want as long as you don’t exceed the breaker’s power rating.
Home Run Switch Wiring
Home run switch wiring is where you wire each light fixture directly to the switch. The advantage of this method is that you can disconnect individual fixtures very easily, and this option might be advantageous if the fixture boxes are harder to access than the main switch box.
Home run switch wiring requires that each hot wiring going from the breaker go directly to the switch’s load terminal. This wiring method becomes awkward as you add more fixtures, and you may need to add another electrical box to accommodate more fixtures.
How to Control Multiple Lights with Multiple Switches
You may also consider the possibility of connecting multiple light fixtures to multiple light switches. It might be useful having a light switch on at either end of a staircase or room, for example (source).
To control light fixtures with two or more switches, you could also connect additional lights in parallel with the fixtures that are already a part of the connection.
It is important to know that the first junction box, the box in which you install the light fixture, has two three-conductor cables coming from one of the switch boxes and a two-conductor cable as an extension to another junction box.
The steps for this connection are as follows:
Step 1: The white wire of the three-conductor cable coming from the right is the switched hot wire and should be taped black.
Step 2: Connect this black-taped three-conductor cable with a wire nut to the black wire of the two-conductor cable and a short black pigtail.
Step 3: Connect the white wire of the three-conductor cable coming from the left with a wire nut with the white wire of the three-conductor cable, and then to a short white pigtail.
Step 4: Now connect the black and white pigtails to your light fixture.
Step 5: In the last junction box, connect the black and white wires to your light fixture.
This method of connecting your circuit is useful for outdoor lighting for your driveway, in that you are able to install a light switch to control all the lights at either end of the driveway. You may also consider connecting this type of circuit at either end of your staircase.
Note that the three-way switches must be at each end, as compared to the four-way light switches that do not need to be connected to either side.
You could also connect a multi-light/multi-switch circuit without using a branch. You can do this by using a four-conductor cable. In this case, it is essential to know that the blue wire is the switched hot wire and that the white wire is the neutral wire.
In this circuit, it is possible to connect as many four-way light switches and fixtures that you would like in a parallel connection on either side — or none at all. But to do this safely, you must use a four-conductor cable from the first light to the last light.
A four-way light switch enables you to control not only multiple lights with one switch but also control multiple lights in the same room from multiple switches at either end of the room.
Consult An Electrician
An article such as this cannot cover all eventualities and codes that apply in all countries and all local municipalities.
For this reason, as well as for the safety of you, your family, and your home, it is best to consult with a local electrician before any type of electrical work.
When electricity is concerned, a little bit of knowledge can be deadly, and it is not worth taking the risk simply to save a little money.
Final Thoughts
Any type of electrical work should never be considered a DIY job with little basic knowledge of electrical work, always get a professional. Connecting multiple lights to one switch is convenient when it comes to creating the right lighting for any large space, and when you would prefer to switch on those lights all at once.
Having multiple light switches for the same set of lights is also necessary for different ends of a room or staircase. The primary limiting factors for the number of lights you can put on a light switch are the amp rating of the circuit and the power drawn by the fixtures.
