Mixing wire


Old 09-22-11, 06:16 PM
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Mixing wire

I have a 1/2 bath and a master bath in my addition.

In the 1/2 bath, because this forum kindly informed me that I needed to have at least one outlet near the vanity, I have ended up with one feed that will have little usage.

I was thinking about splitting the load although the fans and lighting can go on one circuit.

My question is:

If I adhere to only a 15amp breaker, can I mix 20ga and 15ga wire?


2ea 20ga wired outlets to switch box#2
15ga wire from switch box#2 to shower light and fan
Run another 15ga from the same switch box#2 to power 2 outlets next to vanity.

Would that be acceptable?

I think that should fit all scenarios I'm likely to encounter although if you have other interesting mixes, would appreciate learning about it.

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Old 09-22-11, 06:44 PM
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The receptacle needs to be wired wiht 12AWG or larger, GFCI protected, on a dedicated 20A circut, and listed tamper resistant. This circut must only supply the bathroom and all of the wiring must be 12AWG or larger.
Old 09-22-11, 07:00 PM
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As Justin stated, the bathroom is one of the rooms in your house that the NEC has very specific requirements for. You have two basic options for wiring:

Option 1:
20A GFI protected receptacle near the vanity wired with 12ga wire. This circuit may not be shared with any lights or devices in or outside the bathroom. It may be shared with other bathroom receptacles in this bathroom or other bathrooms in the house.
Lighting may be on its own or a shared lighting circuit from elsewhere in the house. 15A or 20A is fine.

Option 2:
Dedicated 20A circuit which powers the receptacles, lighting, fan, etc in ONE bathroom. It may not power anything in another bath nor anything outside the bath. Receptacle must be GFI protected as well.

Now, those are minimum NEC requirements. Most people nowadays would recommend a dedicated 20A circuit for receptacles for each bathroom. Hairdryers, straigteners, and other hair related products often pull up to 1500w each, have two in use at the same time and trip goes the 20A breaker. Bathrooms with multiple sinks (and multiple females) often will have two 20A receptacle circuits, then a 15A circuit for lighting, fans, etc.
Old 09-23-11, 07:55 AM
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I'm sorry, I get a little nervous when people ask electrical questions and make obvious mistakes in the process - you're talking about 15 or 20 ga wire when you should be asking whether 12 or 14 ga wire for a 15 or 20 amp circuit.

Please make sure you know what you are doing, electrical mistakes can cause deadly fires.

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