A 20-amp breaker can handle up to 40 lights (based on 50-watt bulbs). Breaking down the circuit in 10-amp sections would require 2½ amps per section. A 15-amp circuit could handle 30 lights.
The answer depends on how many light bulbs are on each circuit. If there are two or more lamps per circuit, then it is best to use separate circuits for lighting and appliances such as air conditioners, heaters, and dishwashers. The rule of thumb is that you should not exceed 8 lamps per circuit unless you are sure of the wiring ability of your location's code requirements. Local codes may vary, so check with your local utility company or government agency if you have questions about what size circuit you need.
In conclusion, 20 amperes is a sufficient current capacity for a single-family home, but if you want to be safe than you should probably plan for a circuit larger than 20 amps. If you choose to add fixtures such as motion-detection lights or light switches, then you will need additional outlets added to your circuit. You should also try to avoid having any one appliance use more than 10 amps including hair dryers, vacuum cleaners, and dishwashers because these products can be dangerous if they get overloaded.
At 120 volts, a 50-watt light bulb equals less than 1/2 amp of current flow. A 15-amp breaker can handle up to 30 lights (based on 50-watt bulbs). A 25-amp breaker can handle up to 60 lights (based on 50-watt bulbs). On a circuit rated at 20 amperes, no more than 60 lights may be plugged in.
The rule of thumb for wiring lamps is to use one size larger wire than what is called for by the lamp's manufacturer. For example, if a lamp requires 14 AWG wire, then use 16 AWG wire when installing it into an outlet.
Lamps that use 24 volts or less can be wired with 14 AWG wire, but those that use 25 volts or more should be wired with 16 AWG wire.
It's best not to exceed the circuit's current capacity. If you need more power, then install a circuit breaker box.
To figure out "how many lights can be installed on one circuit breaker," you have to know the following: A 50-watt light bulb equals less than 1/2 amp of current flow at 120 volts. You can put up to 30 lights (based on 50-watt lights) on a 15-amp breaker. If you want to be safe, however, go for 20 lights or fewer.
The official term for these small appliances is "general purpose light fixture." They are used to light homes, offices, and other places where general lighting is needed. These fixtures use 25-watt bulbs because that's all that was available when they were designed in the 1940s. Modern versions are required by law in some states to use 35-watt bulbs instead. The number of lamps that can be plugged into a circuit depends on the size of the wires running to it. If the circuit is good and solid, then it should be able to handle the load placed on it. Loading it beyond what it can take will cause it to malfunction later on. If an extension cord is used to bring in more lights, then those cords must be long enough to reach from one end of the room to the other without kinking or breaking.
In conclusion, you can load up to 50-watts per circuit if you use low-voltage wiring. If you choose to load more than this amount, your lights will flicker and some may even blow with dangerous electricity flowing through them.
A fixture with a 60-watt incandescent or halogen bulb uses roughly 1/2 amp, thus a conventional lighting circuit's 15-amp breaker could accommodate 30 of them. That's more than you'd put in most rooms. A 20-amp circuit would handle 45 bulbs.
The standard for residential wiring is 14 amps per circuit, so that's the maximum number of recessed lights you should have on a circuit. If you have more than this, something might be wrong with your house installation. An overloaded circuit is one risk among many dangers that can cause fires or damage to other parts of your home electronics.
The best way to keep from going over the circuit limit is to use only the required amount of light when you're planning your remodel or building project. Recessed lights are great for adding ambiance and beauty to a room, but they also consume energy. You should not leave ones illuminated even when you are not in the room because this will increase your current consumption and possibly overload your circuit. Always shut off the power to a recessed light when it isn't being used.
The Number of Lights You can have a maximum of 12 fixtures divided by 0.9A, or 13 fixtures, for 100-watt lights. If the lights would be operated for less than three hours at a time, the circuit might support 16 fixtures. However, if more than 3 hours of use time is expected, 12 fixtures per circuit is the most that will be allowed.
If you want to be safe, divide the number of lights by 1.0A to determine the maximum load on the circuit. If the answer is less than 10, then there's no problem putting 20 lamps on a 15-amp circuit. But if you need 20 lights or more, you'll need a 20-ampere circuit. We'll assume that you plan to use only 12 lights on the circuit and figure out how large the circuit should be.
Since we're planning for 12 lights, 0.9A will also be needed for the remaining four lamps on the circuit. This leaves us with a total need for 15 amps. Sure enough, a look at the wiring diagram for our house shows that two circuits are marked "15 amp." One circuit is black with red wires, while the other is white with blue wires. Either type of wire can be used in a circuit unless a part of it is supposed to carry a live current; in this case, the conductor must be either black or red.