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November 24th, 2013
|11:12 am - Electricity|
The decorating season is coming up, and since at least one or two of my friends have already started putting out their decorations I thought it might be nice to post a little something about electrical safety. Hopefully it is clear, easy to read and helpful.
There are three factors you need to consider when you plug anything into an electrical outlet:
How much the total "load" is on the cord.
How big the wires are in the cord.
How long the cord is.
The load is usually noted as the number of Amps (A) used OR the number of Watts used. As a rule of thumb: each Amp = 100 watts (this gives you a little safety margin).
In older buildings most breakers or fuses are 15A (15 AMP) or less. So that is the total amount of energy available SAFELY from that breaker/fuse. Most other breakers/fuses are 20A.
The wire leading to the breaker/fuse is called a circuit. Each circuit usually goes to several outlets and/or lights. In San Francisco there are a lot of apartments that only have one or two breakers for the whole unit. The trick here is to add up the load from ALL of the things that are plugged into that circuit. So one circuit might have the refrigerator, three lights AND your wall outlet.
Cord wire size is called "guage". The bigger the number the smaller the wire. So 18 guage wire is very small and 12 guage wire is several times bigger than 18 guage. The size of the wire dictates how much electricity can pass through a given length of wire before it fails. Why should you care? Well, because if you try to run a long cord with a load that is too heavy for it, the wires can heat to red hot, melt the insulation and burn anything they touch.
If you plug a 15A load into your outlet that already has your refrigerator and those lights plugged into it you might or might not blow the breaker/fuse, but you WILL heat up the wires in your walls.....
Cord length also has an effect. There is mysterious marking on our electrical cords called Volts, Voltage or V, is a measure of the electrical pressure (like water pressure in a hose). With good water pressure you can power wash your car easily, but as the pressure gets lower it gets harder and harder to do the job.
The longer the cord, and the smaller the wire, the faster you loose electrical Voltage pressure in the cord.
Here are some guidelines from my Backstage Handbook by Paul Carter (sort of a Bible of tech info and well worth getting a copy even if you aren't a stagehand.) These guidelines make sure that your Voltage, or pressure doesn't drop more than 1 to 3 volts.
With a load of 10 Amps (1,000 watts) the longest 18 guage extension you should use is 25 feet.
With a load of 10 Amps (1,000 watts) the longest 12 guage extension you should use is 100 feet.
Now, we ALL have exceeded these guidelines more or less safely, partly because most of our lights and tools will run on slightly reduced voltages, but it provides a starting point for safety.
So you have this tangle of cords, none of them have a mark on them and you have NO IDEA of their capacity. Be aware that diameter or size is very deceptive. Some 18 guage cords are larger than 14 guage cords. How can you figure out if they are overloaded? Put your hand on the cord, near the wall outlet. Is it warm? Then it is overloaded. A properly sized cord will not get warm from the flow of electricity through it. Re-check your wire after 20 minutes or half an hour, constant flow of electricity can gradually warm up wires that are cool at first.
Cord wires often begin to break where they bend, just at the actual plug end. The size of the wire might be fine, but if half of them are broken then the cord must be repaired or replaced to be safe.
In general ANY electrical part that is warm or worse, hot, is a hazard that should get IMMEDIATE attention, from the fuse/breaker box to the red bulb on Rudolph's nose.
Have a good winter season and stay safe!
November 2nd, 2013
|01:34 pm - Philosophy Part 2|
Thank all of you who replied to the friend vs community question. All of the answers were thought provoking and much appreciated.
October 30th, 2013
|08:16 pm - Philosopy|
For you, what is friendship?
Is it different from community, and how?