breaker size for 6/3 cable

Feb 07, 2010 2 Replies

I am putting a subpanel in the basement (Tigard, Oregon). There is already a 6/3 copper cable run down there. This cable will be attached to a breaker in the main panel. What is the maximum size breaker I can use? I have read conflicting stuff. Is it a 50 amp or 60 amp breaker?



Thanks, Jess Keyword = jessjoemama


It's 55 amps, the nec allows you to go to the next size breaker 60 amp

How long is the run from the end of the 6/3 cable in the basement where you want to install the sub-panel from the main breaker panel it will be fed from... If it is a long run, your ampacity on that line will be reduced as you would have to run a bigger sized wire to compensate for the greater distance from the main panel to get the same amperage service to that location...

You see this in situations sometimes when you have a circuit that feeds a distant part of your house, far away from your breaker panel, you would run a wire a size larger than you what is "needed" to compensate for the longer run...

~~ Evan

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