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Electrical Equipment vs Electrical Load

In your home you have many types of electrical equipment that use electricity. Each one is an electrical load.

If all of the equipment operated at the same time, you would have your maximum amount of load, or current draw. Fortunately, not all equipment will be operating at the same time. This means that your load will vary as different electrical equipment is used and the amount of loading will be something less than maximum.

Electrical appliances, such air conditioners and refrigerators, use motors and typically draw more current than most other electrical equipment in the house, except for maybe your electrical stove. Your table lamp, with a single bulb, would draw considerably less than any of those.

I am using the term ‘electrical load’ very loosely. I am using it as a generic reference to all the different electrical devices, equipment, appliances, etc., in your home that uses electricity. The actual electrical load is expressed in the amount of power used and this is measured in WATTS.

Electrical Equipment vs Electrical Load

Some electrical equipment that you use in your home comes labeled with a wattage rating. Since WATTS is POWER the label is telling you how much load the equipment is going to put on your system. But, with a little bit of extra knowledge on your part, it will also give you an idea of the current it will draw. Remember, current draw is expressed in amperage or amps.

So, why do you need to know that? Well, if you know how much current you are adding to a circuit, you may be able to prevent overloading your circuit(s) and tripping the breaker or blowing a fuse at a most inopportune time.

Here is how simple it is. All you do to find the current is divide the wattage rating by the voltage the electrical equipment is going to be used on. Here is a list of examples:

  • 60W light bulb – 60W divided by 120V = .5A
  • 100W light bulb – 100W divided by 120V = .83A
  • 1200W space heater operating at 120V – 1200W divided by 120V = 10A
  • 1500W microwave operating at 120V – 1500W divided by 120V = 12.5A
  • 4000W central heat operating on 240V – 4000W divided by 240v = 16.7A

There is one more thing I want to point out to you about wattage rating and power. When you think of WATTAGE or POWER, also think of HEAT! Everything that uses power generates heat.

The higher the wattage rating on a space heater the more heat it will create. This is also true for light bulbs. The higher the light bulb wattage the higher the heat output from the bulb.

Most light fixtures are rated for 60W lamps but to increase light output they are sometimes replaced with 100W or higher. When this happens the heat output is increased by about two thirds and could cause a fire. BE CAREFUL! Do not exceed the fixture manufactures maximum wattage rating!