A 60-watt incandescent bulb may offer the same amount of light while using 10 watts or less, which is comparable to a current draw of 12 amps. 180 or more bulbs can be controlled with a 15-amp circuit. Most people will need at least 20 amps to run all their appliances simultaneously.
Appliances that use high amounts of electricity include air conditioners, heat pumps, and dishwashers. They require large currents to operate their motors efficiently. Small appliances such as lamps, fans, and mixers also use small amounts of current but they are multiplied by how many you have running at one time. For example, if you have 20 lamps on in a room plus the lamp in the next room, it can add up to a lot of current flow. Electricity flows from the power station to the points where it is needed most. So, if you have multiple devices that can use electricity at any given time, it is best to provide them all with their own separate circuit rather than using a single heavy circuit. Separate circuits prevent your appliances from being damaged by too much voltage or current.
The amount of current used by an appliance can only be estimated based on its wattage or power rating. For example, a refrigerator/freezer uses about 10 to 30 amps when it is fully loaded but it could use as little as 2 amps if it was almost empty.
When using 10 watts or fewer, each CFL or LED bulb produces the same amount of light as a 60-watt incandescent bulb, resulting in a current consumption of 1/12 amp. As a result, a 15-amp circuit may securely power 180 or more CFL or LED lamps. For 20-amp circuits, you will need 240-volt outlets for these bulbs.
The voltage used by a CFL is about 9 volts, so it can be plugged into a normal outlet. However, because they are compact and lightweight, they do draw some current when they are off. This low-current drain causes a small loss of energy over time, so they should be replaced once per year anyway. A battery-powered nightlight is a good idea even if you only have 5-foot cables to work with!
CFLs emit almost no heat when they are off, so they are ideal for places where heat is an issue. The only real down side to them is that they contain mercury vapor which can leak out if they are broken. This is why they should be placed in a protective container until they are ready to discard. Some cities may have additional restrictions on how waste products are handled, so check your local regulations before disposing of old CFLs.
The current usage of CFLs is still somewhat controversial because there has not been much research done on the long-term effects of living with them on the environment.
8.3 volts A 100-watt bulb, for example, will consume 8.3 amps in a 12-volt circuit. A 120-volt circuit will allow the lamp to run at 10 watts instead.
The actual load that a lamp places on the wiring system is called its "operating voltage." The operating voltage of a lamp is the voltage between the terminals of the lamp when it is supplying energy to the rest of the circuit. For example, if the circuit operates on 120 volts, then the operating voltage will be 120 volts. If the circuit operates on 24 volts, then the operating voltage will be 24 volts as well.
It is important to remember that the actual load that a lamp puts out is called its "operating current." The operating current of a lamp is the current through the lamp when it is operating and supplying energy to the rest of the circuit. For example, if the circuit operates on 120 volts, then the operating current will be 120 milliamps (mA). If the circuit operates on 24 volts, then the operating current will be 4 mA.
As long as the operating voltage and current are within specified limits, any lamp can be used with any previous design house electrical system.
Two responses A 120 volt, 15 amp circuit can supply 1800 watts (unless it is a "continuous load," in which case it can only provide 1440 watts). A "regular bulb" is probably a 60 watt incandescent bulb. This implies that a 15-ampere circuit may support up to 30 lamps (likely a bit less to compensate for losses elsewhere in the circuit). A normal household circuit is on the order of 20 amps, so this means it can supply about 300 watts or more. A single CFL bulb consumes about 10 watts, so this circuit could easily drive that as well.
The answer depends on how much power your lights use at any given time. If you have them all off then they draw no current so they would not consume any energy. If you turn all of them on then they will consume maximum power and be drawing full voltage from the source even though none is being sent to the lights. This means their total power consumption will be maximum even if some portion of the time only a small amount of current is being drawn.
In a typical situation where most of the time only a few bulbs are on but there are times when all of them are on, it's helpful to think in terms of average power rather than maximum power. Average power is calculated by dividing the total power used by the number of hours in the year. In our example, this comes out to about 180 watts per hour, which is not very high compared to other appliances such as heaters and air conditioners.