PlanetChristmas
and Figuring Power Needs
If you have any questions or concerns
at all about electricity, please consult a licensed electrician
You've
got thousands of Christmas lights yet you have no idea how many can be plugged
into a typical wall socket. We're here to help.
Let's use a simple electrical formula. Power (in watts) = Voltage (in
volts) times Current (in amperes) or P=VI which is what
engineers like to say (why "I" is an abbreviation for current is a closely
guarded secret by electrical engineering purists.)
In the United States, a typical wall outlet is 120 volts and all Christmas
light strings are wired to handle it. Your wall outlet is usually wired in
parallel to several others and connected to some sort of circuit breaker or
fuse, usually 15 or 20 amps. Your goal is to not overload the circuit
breaker/fuse. It's good practice to never put more than 80% load on your
breakers/fuses... strictly as a safety measure.
You will have to figure out if the outlet
where you want to plug in your Christmas lights is on a 15 or 20 amp circuit
breaker or fuse. The easiest way to find out is plug a radio in and turn
it up pretty loud. Go to you electrical panel and start turning off
circuit breakers or unscrewing fuses. When the radio stops making noise,
you're on the right circuit. The breaker/fuse will tell you how much
current that circuit can handle.
If you have a 15 amp circuit with 120 volts and factor in an 80% load,
using the P=VI equation (P=V*I*0.8) you can have a total load of (120*15*0.8=)
1440 watts.
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If you have a 20 amp circuit with 120
volts and factor in an 80% load, using the P=VI equation (P=V*I*0.8) you can
have a total load of (120*20*0.8=) 1920 watts.
Use the chart below to get a pretty good idea how much power different types
of Christmas lights consume. There are plenty of exceptions to the chart
since there are so many different types of lights. To see if you're close,
check the tag at the plug-end of a new string of lights and it will tell you how
much current it consumes... in most cases, it will match up with the yellow
column in the table and you can feel comfortable with the numbers
|
Light String Description |
Lights /
String |
Total
String
Watts |
Total
String
Amps |
Total Strings
for 15 amp
Circuit
(80% usage) |
Total Strings
for 20 amp
Circuit
(80% usage) |
| mini-lights |
20 |
16 |
0.13 |
90 |
120 |
| mini-lights |
50 |
20 |
0.17 |
70 |
94 |
| mini-lights |
100 |
40 |
0.33 |
36 |
48 |
| mini-lights |
150 |
60 |
0.51 |
24 |
32 |
| mini-lights |
200 |
80 |
0.66 |
18 |
24 |
| LED-lights (C6-C7 look-a-likes) |
25 |
2.4 |
.02 |
600 |
800 |
| LED-lights (mini look-a-likes) |
60-70 |
2.6 |
.03 |
554 |
738 |
| C7 bulbs (5 watts each) |
25 |
125 |
1.04 |
11 |
15 |
| C9 bulbs (7 watts each) |
25 |
175 |
1.50 |
8 |
10 |
| 60 watt light bulb |
1 |
60 |
0.50 |
24 |
32 |
| Compact Fluorescent Light (equal to a 60 watt
incandescent bulb) |
1 |
14 |
0.12 |
102 |
137 |
| 100 watt light bulb |
1 |
100 |
0.75 |
14 |
19 |
| 150 watt floodlight |
1 |
150 |
1.25 |
9 |
12 |
rope light at 5.5 watts
per foot and string is
18 feet long |
216 |
99 |
0.82 |
14 |
19 |
|
Inflatable Description |
Total
Watts |
Total
Amps |
Maximum
inflatables
for 15 amp
Circuit
(80% usage) |
Maximum inflatables
for 20 amp
Circuit
(80% usage) |
| inflatable (typical 4') |
52 |
0.43 |
27 |
36 |
| inflatable (typical 6') |
58 |
0.48 |
24 |
32 |
| inflatable (typical 8') |
80 |
0.66 |
18 |
24 |
| inflatable (typical 12') |
86 |
0.71 |
16 |
22 |
Rule
of Threes: On just about every string of Christmas lights you buy
it will have a sticker saying to never plug more than three of them together
in series. Don't try and bend the rules by sneaking in an extra string
or two. The wires powering those little lights are small and not
designed to handle a lot of electrical current. Violating the rule of
three's will get you blown fuses, melted wire or a fire.
Plugging
Plugs into Plugs and the Rule of Threes: You can always plug the
plugs into the top of other plugs. Theoretically there is no limit
other than the total amount of current being supplied... but it's good
practice to stick to the rule of threes... no more than three plugs plugged
on top of each other and never connect more than three strings in series.
Always be on your toes when working with electricity. Why? The
stuff really can kill you. As an example,
click here for a great video on arching. Want to see a guy get
zotted by high voltage... pretty gruesome, but it helps put things in
perspective. Click here by the high voltage strike.
If you have any questions or concerns at all about electricity, please
consult a licensed electrician
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