I recently purchased a house that failed inspection because of some oversized breakers. Of course, I had the seller get the circuit breaker fixed before finalizing the purchase, but I feel it is important for me to understand some basics around my circuit breaker. Mostly around 15 amp and 20 amp breakers and their correct cabling requirements. And also double pole vs tandem single pole vs "normal/regular" single pole.
So far this is what I've gathered from all the reading I've done:
- A 20 amp circuit requires 12 gauge cabling, and can support a 20 amp outlet or 15 amp outlet (as long as there is more than one outlet)
- A 15 amp circuit can use 14 or 12 gauge cabling, and can only support a 15 amp outlet
- A double pole circuit takes up 2 spots on the circuit breaker for a total of 240v. Amperage may vary depending on the specific circuit you put in and the required cable gauge will be affected as well
- A single pole tandem circuit can go into a circuit breaker only where the circuit breaker designates spots for it.
- A single pole (normal/regular) circuit can go in spots designated for them
- Can a single pole (normal/regular) circuit breaker be used in spots designated for tandem? Almost like backward compatible; the circuit breaker can accept normal/regular or tandem. You typically use normal/regular until you need to upgrade to tandem?
- What does it mean that the circuit breaker was oversized?
- I probably frustrated you calling it a normal/regular circuit, what is it actually called?
- Are there are other general rules I should know?
Please correct me on anything that I think I am correct on, but actually was not correct. Also, I know one of my circuits at the bottom are flipped, I will be looking into that soon.