Home
Firehouse Christmas Lighting
Managing Electrical Power PDF Print E-mail
For outdoor lighting, your number one concern will always be maintaining enough power through your string(s). Most homes have a single 16 amp plug in the front and back yard. However, because that circuit is normally shared by a room in the home, you may not be able to use all 16 amps. If you are running your lights off of a single plug, you cannot exceed 16 amps for that plug, and to be safe, you should limit the number of amps to 13. Now that you know your limits, you need to be able to calculate the number of amps for your string(s). To calculate the number of amps being pulled by your lights, use this formula:

Number of feet times number of watts divided by 125 volts=number of amps
(C7 lamps draw 5 watts, C9 lamps draw 7 or 10 watts)

Example:
For 200 feet of C7 Lamps: number of feet x 5-watts = 1000 watts
Divide 1000 watts by 125 volts= 8 amps

Since minilight lamps are not rated in watts, you need to refer to the following chart to find the number of amps:

35/50 light strings: 0.2 amps
100 light strings: 0.4 amps