Breaker Wattage Limits

Discussion in 'Electrical Forum discussion & Blog' started by my3angels, Jul 26, 2011.

  1. my3angels

    my3angels New Member

    Messages:
    8
    Location:
    Redding, CA
    The home I bought 4 years ago has been added onto, but it seems they connected to existing breakers instead of running new conduit and another breaker. If I use more than one appliance in the kitchen, the 15 watt that's installed will kick off. A friend of mine told me just to install a higher wattage breaker (like a 30 watt) but I was under the impression the breaker wattage is set to prevent possible overload and fire. How do I determine what the limit should be for each breaker?
  2. SacCity

    SacCity In the Trades

    Messages:
    189
    Location:
    Sacramento, CA
    The "Amperage" of the breaker is sized to protect the wire in the wall.
    For the most part it is working well as there are a lot fewer home fires than there used to be...
    So the Amperage rating on the kitchen circuits will be determined by wire size. As a generall rule most house , hold wire is 12 gage, which is good for 20 Amps.
    On lighting there may be 14 gage wire, and on appliance circuits cloths dryer is generally a 30 amp braker for 10 gage wire. The smaller the wire the higher the gage number or conversly the smaller the wire gage the larger and more amps (power) that it can carry.
    Michael
  3. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    my3angels, PLEASE DO NOT listen to this friend when he gives you home improvement advice. ESPECIALLY electrical!
    This guy is going to get someone hurt or killed. You can tell him I said so!
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,020
    Location:
    New England
    For today's codes, you need a couple of 20A circuits in the kitchen for outlets, and many appliances state they should be on their own circuit, rather than being shared. So, depending on what's in the kitchen, you may want lots of circuits (say frig, stove, dish washer, vent hood, microwave, etc.). True, you can share some things, but if the manufacturer wants its own circuit, you should probably go that way. An older house may not have a big enough panel for today's power requirements.
  5. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    Well, not so fast. A fair mix of 12 & 14 is average. The only way to know is to check it, by reading the sheath or physically looking at/measuring the conductors.
    Also, there will be/should be NO #10 gauge wire on general lighting and receptacle circuits. These circuit are limited to 15 or 20, so using #10 in a typical home is unnecessary, even wasteful.
  6. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,347
    Location:
    Cincinnati OH
    do not attemept this you have to hire an electrician!!!!!!!!!
    Last edited by a moderator: Jul 27, 2011
  7. my3angels

    my3angels New Member

    Messages:
    8
    Location:
    Redding, CA
    I was worried about the same thing. He seemed irritated when I wouldn't use the 30 he picked up, but I figured better to be safe with my children, then to hurt his feelings.
  8. my3angels

    my3angels New Member

    Messages:
    8
    Location:
    Redding, CA
    I'm a single mother with three children, so I was looking for a safe quick fix until I could afford an electrician. There are many other problems with the house that weren't found in the original inspection, and this seemed too important for that 'temporary quick fix' he'd suggested.
  9. my3angels

    my3angels New Member

    Messages:
    8
    Location:
    Redding, CA
    I spoke with an electrician after I'd found this problem and he said these older homes wiring weren't built for microwaves so the breaker will continue to kick until the house is rewired. I believe the breaker for the entire kitchen, the central heat/air, one of the bedrooms, and the laundry area are all connected to one 15 watt breaker.
  10. my3angels

    my3angels New Member

    Messages:
    8
    Location:
    Redding, CA
    So the 15 amp breaker should not be increased until confirmation of the wire gage is made? That makes perfect sense, and one of the reasons I wouldn't allow it to be installed was I thought it was designed that way. Thank you for the information.
  11. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,161
    Location:
    Houston, TX
    Good Morning.

    That is correct.

    It is better to be safe than sorry.


    Have a Great Day.


    DonL


    P.S. P = I * E
    Last edited: Jul 27, 2011
  12. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    You don't need your house rewired. You just need a few new circuits run.
  13. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,647
    Location:
    Cave Creek, Arizona
    The wire size will determine the maximum breaker you can use, but you CANNOT depend on the wire size at the breaker, because if they have a 15 amp breaker, even with #12 wire from it, they might have reduced the wire size farther away knowing that it would be connected to a 15 amp breaker.
  14. BobL43

    BobL43 DIY Senior Member

    Messages:
    1,792
    Location:
    Long Island, NY
    Watt? PF "message was too short, so I typed words within quotes!"
  15. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,020
    Location:
    New England
    Watts are a measure of power usage, amps are a measure of current flow. They're related, but not the same thing. Circuit breakers for homes are rated in the number of amps they can supply through the wiring safely - the bigger the wire, the more amps it can supply and the bigger circuit breaker you can install to protect that wiring. 15W will light a compact florescent light bulb (well, at least some of them), but wouldn't power much of anything else. Power(watts) = Current(amps) * voltage(think of this as the pressure). So, a typical 15A circuit with 120vac can safely provide a max of 1800W of power. You don't normally want to be running the circuit at max.
  16. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    If you were to follow your "friends" advise there is good chance you and your kids will be living in a new house. That is after the current one gets rebuilt after the fire.
  17. BobL43

    BobL43 DIY Senior Member

    Messages:
    1,792
    Location:
    Long Island, NY
    my post had a little joke "PF" so as us who know, know that E*I = volt amps which does not take into consideration any power factor (PF). However, Amps is amps, and the breaker is rated in amps as all here except the original poster have said. do I need my shields up now? Yes, the formula IS P=EI (apparantly), but that's another pun not intended. Depends on the load, especially when inductances are involved, like motors with poor power factors.
  18. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,161
    Location:
    Houston, TX
    I think that maybe she was a little confused at first about Watts and Amps, But she corrected herself on here last post.

    Jim did a good job explaining it. (Way to go jadnashua)

    Most Appliances are rated around 1500 Watts Max so that they have no problem working on a 15 amp circuit.


    DonL
    Last edited: Jul 27, 2011
  19. BobL43

    BobL43 DIY Senior Member

    Messages:
    1,792
    Location:
    Long Island, NY
    Jim who? Just kidding!;) at work we used to have an eastern European guy named Jim with a name so long, we all called him "Jim Who?" He changed his name to Jim Rockwell after he became a US citizen.
  20. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,161
    Location:
    Houston, TX

    Sorry, I should have said jadnashua, but my mistake.

    He seems to be very good at explaining things, and the thing I like most is that he knows what he is talking about.

    jadnashua is the best.

    Sorry for the mix up.


    Have a Great Evening.


    DonL
    Last edited: Jul 28, 2011
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