30 AMP 277VAC Triple Pole Breaker
Inside a breaker from How Stuff Works
An Electrical Panel with AC Breakers

Marc Donavan of HomeEditionPlus talks about the use and importance of circuit breakers in home electrical wiring. He also discusses the importance of correct cable selection such as a #14 wire which requires a 15 Amp circuit breaker, whereas #12 wire is designed for 20 Amp circuit breakers.

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I would also like to share a video from Bill Allen of TexasHomeInspections that shows the inspection of main electrical panel boxes. This 7:15 minute long video starts with the explanation of oxidation’s effect on the bussbars and circuit breakers. Also you can observe 220V receptacle inspection and the related circuit breaker. Please note how to connect the double leg circuit breakers at 2:02 minute mark.

At 4:00 you will see a sub panel box with ground wires and then learn why the number of feeder cables has to be the same in all sub panel boxes in the same system. Note that the grounding wires needs to be screwed to the box itself.

At 5:55, notice the taped cable splice at the service drop is not approved; if cables are not protected from sun and rain exposure they become a fire hazard.

 

 

Comments

Jon Steel commented 13 years 9 months ago

Thanks for putting this together.    Understanding circuit breakers can be tough for installers moving into solar.  Is there a chart you can point me to that shows how to size a circuit breaker?

Jon, thank you. I think that's a great question.

I'd like to refer to NEC Table 210.24 (PDF).

Circuit Wires
(copper conductors)
#14 #12 #10 #8 #6
Overcurrent
Protection
15 A 20 A 30 A 40 A 50 A
Missing Missing commented 13 years 1 month ago

You will find many project management centers offering PMP certification preparation for people interested in becoming certified

Published
13 years 9 months ago
Written by
Levent Bas