mixing 12AWT and 14AWT wire

Discussion in 'Electrical Forum discussion & Blog' started by Taylor, Apr 10, 2009.

  1. Taylor

    Taylor New Member

    Messages:
    143
    Location:
    Northern Joisey
    Electrician tells me that you cannot mix 12AWT and 14AWT wires on the same circuit, according to code. I have run 12AWT on 15A circuit to avoid voltage, with 14AWT to individual light fixtures. I have also run 14AWT to light fixtures from receptacles on 20A circuit. Do I have to upgrade everything to 12AWT? What about pancake boxes, which AFAIK can only take 14/2?
  2. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    992
    Location:
    NY State, USA
    Mixing wire sized is certain not prohibited by code, but it is not a workman like installation and can cause issues down the road.

    If this is done you MUST size the breaker according tot he smallest wire on the circuit. So, your 20A circuit with #14 to the lights is not complaint and should be fixed. Either replace the breaker with a 15 or replace the #14 with #12.
    Hopefully you did not create and even worse violation and tap off a kitchen/DR or bath receptacle circuit for lighting.
    The argument that all you are doing is tapping off for a light fixture is NOT valid.

    It is extremely rare that you would need to upsize wire in a typical residential installation to counter voltage drop. If you do though it is a good idea to use all the same wire. If you do mix wire sizes IMO it is a good idea, and IMO should be code required, to label the wire in the panel to only be used for the smaller breaker. Someone down the road might see #12 and have no idea that the circuit has #14 on it and replace the 15 with a 20A breaker.

    Some people have the misguided idea that they should use all #12 and use some 15 amp breakers so they can someday "upgrade" the circuit to a 20A. They feel there is some safety factor built in by doing this. This is completely untrue, unless of course you have an extremely long circuit and voltage drop is an issue as I mentioned before. There is NO "safety margin" by doing this. All you are doing wasting a potential 5 amps of circuit capacity by under sizing a breaker.
  3. Taylor

    Taylor New Member

    Messages:
    143
    Location:
    Northern Joisey
    Thanks, the pancake boxes are all on 15A circuits. I will upgrade any 14AWG wire on 20A circuit, there are a couple of lengths going from switch to light. All of this is inspected, but using MC wire so the inspector missed the size of the conductors.

    Not sure what you mean by:
    Kitchen and bathroom I get, but DR? All bedrooms have a single circuit that powers both lights and receptacles (this is the work the electrician was doing).

    I understand the problem with mixing 12AWG and 14AWG. Kitchen receptacles are on 15A breaker and 12AWG wire. Receptacles keep blowing whenever anything drawing significant current is plugged in, but not willing to upgrade to 20A breaker because I don't know what is in the walls, and given what I've found outside.....
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,917
    Location:
    New England
    this is the reason why current code requires 20A circuits in the kitchen for recepticles.
  5. killavolt

    killavolt In the Trades

    Messages:
    33
    Location:
    Southington CT
    I think mixing lighting circuits with receptacles could be a safety issue, especially with arc-fault breakers in the mix. If a circuit breaker trips because of something plugged in, you could be navigating to the panel in the dark. I keep lighting circuits seperate from receptacles in residential work.
  6. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,532
    Location:
    North Carolina

    Yea I know just exactly what you mean about walking around in the dark like that.

    A couple of years ago during a bad ice storm the power went off and we had to walk around in the dark for several hours.

    Now if the idiot that wired the house hadn’t put the lights and receptacles on the same circuit trying to save a buck then maybe this wouldn’t have happened.

    Myself I installed nothing but two bulb fixtures with each bulb on its on circuit just in case one breaker trips there will be a circuit for the other bulb. When I can I will install a multi bulb fixture with each bulb on its own circuit.

    The inspector turned me down one time on a dinning room fixture. He said that eight circuits over filled the box. The fixture had eight bulbs.
  7. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    992
    Location:
    NY State, USA
    Not me, although I do like Mike's approach.

    The whole "you'll be in the dark" mentality is completely flawed. To go so far as to say it is a safety issue is a bit dramatic I think.
    So what, if one breaker trips the whole house will be in the dark? No, if you combine lighting and receptacles on a circuit there will be LESS lighting on a circuit so it will be LESS dark as you navigate your way on the long journey to the panel board on the island of forgotten dreams. :p

    Besides, if only one circuit trips wouldn't there be other circuits close by that are still on? I know for a fact that unless you happen to be in a closet at the time there will be more than enough residual lighting from other sources to get you where you need to go safely and in comfort.
  8. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,532
    Location:
    North Carolina
    In my 58 years of lighting candles and lanterns I have had more power failures than tripped breakers.

    My house has nine rooms and a full basement. Only three of these rooms have a lamp plugged into a receptacle and the basement where the panel is not one of them so the lamp idea is worthless to me.

    I always carry a candle in my pocket along with a kitchen match just in case the breaker trips. It is a good thing that I do this as the other day I was having a lump removed from my leg when the power went off in the operating room. If it were not for that candle the doctor might have tripped and cut my leg completely off.

    Another time when I had already used my candle up I was shopping looking for some raisins when the breaker tripped out leaving all the shoppers in the dark. Instead of raisins I got a box of prunes and used all the toilet paper in the house. I think I will start carrying two candles. The good thing is I lost 25 pounds after eating that whole box of prunes.
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,508
    Location:
    Cave Creek, Arizona
    light

    Eight circuits to a fixture because it has eight sockets? Someone is either paranoid or obsessive.
  10. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,532
    Location:
    North Carolina
    Just wanting to make sure that no one is caught in the dark in case one or more of the breakers trip.

    I for got to add that each bulb was also on a battery back up just in case one battery went dead.
  11. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    992
    Location:
    NY State, USA
    Jeeze Mike. You are in rare form today. I love it! :D :p
  12. Scuba_Dave

    Scuba_Dave Extreme DIY Homeowner

    Messages:
    885
    Location:
    South of Boston, MA
    Yeah, I've had way more power outages then breaker trippings
    My last house I had candles, oil lamps & matches all over the house. That way if the power went out I was never far from a light
    I do tend to put lights seperate from outlets, just a habit
    The vacuum takes 12a
    We very rarely have enough lights on to matter on an oputlet circuit. And with CFL's the wattage has dropped even more

    The one place I do like the lights seperate from the outlets is the bathroom. The wife's hair dryer takes a bit of power
  13. Taylor

    Taylor New Member

    Messages:
    143
    Location:
    Northern Joisey
    I hope that those installing single-bulb circuits make sure to use #10 wire. Nothing will kill a light bulb faster than voltage drop.
Similar Threads: mixing 12AWT
Forum Title Date
Electrical Forum discussion & Blog Intermixing wire size Aug 12, 2008

Share This Page