Episode 30 – Lumens Or Watts? – THE BRIGHTNESS OF LIGHTS

A lot of people still use wattage to talk about the brightness of lamps, when in reality lumens are the measure of light output. Wattage is still useful to know as an electrician, but we need to stop using it to talk about the BRIGHTNESS of a light.Wattage Wattage is used as a unit of measure for electrical consumption in a piece of equipment. It’s talking about how much power is being used, and has nothing to do with how much light is being put out, what the color of the light is, or how efficient it is at doing so.You really only need to know wattage for 2 reasons. One is to calculate how many lamps you can install on a circuit. For instance say you have a 20-amp, 120-volt circuit that you need to install 10 60-watt lamps on. You can do the math using the PIE wheel to figure out how much wattage you have to work with on a full circuit. To do this you’d multiply 120v x 20a = 2,400 watts max. Then you’d take 10 x 60w to calculate how much wattage your 10 60-watt lamps will use – and you get 600 watts. 600-watts can fit into a 2,400-watt circuit so you know you won’t trip a 20-amp breaker with this installation. Again, this is simply telling you how much power the lamps are consuming, not anything about their brightness.The second reason you’d want to know watts is for calculating your energy bill. Every electrical meter uses total wattage-used over time. So you’re charged based on watt-hours. If you know how much the power company charges you per watt-hour, as well as how many watts your building/home uses – you can calculate your electric bill within a reasonable amount of certainty.  LUMENS Where brightness of a light-source is concerned, you want to use lumens as the unit of measure. Lumens tells you how much light is coming out of a light-source, not how much energy it is consuming to do so. A 500 lumen incandescent lamp at 25-watts will be relatively dim. However a 12.5-watt LED that puts out 1,000 lumens of light, will be fWant to learn more about becoming an electrician or mastering the craft? Visit ElectricianU.com for courses, resources, and everything you need to succeed!

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