National Electrical Installation Standards

Standards as High as Your Own

 
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Wednesday, January 18, 2017

Question:

My code question for the day............

Always been curious about & have accepted the fact that it is what it is but I've asked numerous Electrical Foreman, Project Managers & Estimators (both old & young) why is it that a two-pole single phase isn't called 2-phase as a three-pole is called 3-phase? To date, all of my answers have been ....... don't know. So I'm hoping you could answer this question for me that's been nagging at me for years.

Thanks in advance!

John Reynolds

A

Answer:

Hey John thanks for your question. The word phase is used several ways such as going through a phase during teenage years or they are out of phase (out-of-line) with something. If we use a generator as our electric supply source for example and the output is single phase then the winding or windings are "in line" or in phase. A three phase generator system has each winding 120 electrical degrees "out of phase" to the previous one. Three times 120 gives us 360 degrees in a revolution of the generator. It's not good to let something nag you for years and let us know if more explanation is necessary.

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