For example, the maximum number of 7-watt C9 bulbs that can be used on a 15 amp circuit on a standard outlet is calculated thusly: • 120 volts x 15 amps = 1800 • 1800 x 0.8 = 1440 ...

And that is "don't overload circuits over and over and over again." Doing so — slowly, but surely — will fatigue the wire inside the wall. You might eventually end up with a dangerous condition.

Find out how many watts each of your circuits will hold, and don’t exceed the limit. Following this simple rule will add longevity to your electrical system and maintain safety. Advertisement ...