What am I missing?

Old 07-06-02, 03:56 PM
Joe Rockhead
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Question What am I missing?

Several years ago I ran a 10/2 line for my upstairs AC window unit - 20 amp receptacle - 20 amp breaker - nothing else on the line. Now I need to put an AC unit in another room upstairs. Can I tie in to that same 10/2 line and add a 30 amp breaker or will that make the outlets the weak link in the chain resulting in a nice little fire in my walls?!

Old 07-06-02, 06:00 PM
HandyRon's Avatar
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A 30 amp circuit requires 30 amp receptacles.
Many smaller A/C units have a nameplate with a max breaker size of 20A, check yours. It the A/C units (new and existing) permit a 30 amp breaker for protection on each, then consider replacing the 20 amp recept with a 30 amp (you will have to replace the cord on your existing unit).
Check their ratings so as not to waste your time, to prevent false tripping of the breaker when both units cycle-on.
Old 07-06-02, 07:33 PM
Join Date: Sep 2000
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Ron has hit on the two problems: (1) you won't be able to plug your existing A/C into a 30-amp receptacle, and (2) you will most certainly trip the breaker if you run both A/Cs at the same time.
Old 07-08-02, 03:29 AM
Joe Rockhead
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That little voice nagging me was right - thanks guys.


Yup, could only use 20 amp breakers. Ran another wire from super hot attic down to lovely crawl space then over and up to the box. DIY is just so much fun!

Thanks again.

Last edited by Joe Rockhead; 07-08-02 at 05:38 PM.

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