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Wall Current

  1. Mar 18, 2004 #1
    I know this isn't quite what you mean when you say electrical engineering, but, how many amps is a standard three-pronged edison plug rated at? Also, what is common house wiring rated at?

    I believe that a three-pronged plug is rated at 15 amps and that logically the wiring should be able to carry at least that. By my calculations then in the US with good ol' 120-volts you should be able to carry 1800 watts on a wall outlet.

    I'm just a layman at electricity and I just wanted to be sure. As much as some people dream about it I don't want to burn down my school.
  2. jcsd
  3. Mar 18, 2004 #2


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    Staff Emeritus
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    Gold Member

    You're correct, most circuits in most buildings will carry 15 or 20 amps. If you try to pull more than that, you'll just pop the circuit breakers.

    - Warren
  4. Mar 18, 2004 #3


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    Staff: Mentor

    Yes, but as you know, generally more than one outlet goes to the same breaker. When designing a building, you put a maximum of 10 outlets (depending on known usage) on a circuit and assume 180w per outlet.
    If you know (for example) that an outlet supplies power to a window air conditioner, you put it on its own circuit.
  5. Mar 19, 2004 #4
    Right Russ. Code says "The rating of any one cord and plug-connected utilization equipment shall not exceed 80 percent of the branch circuit ampere rating. Fixed in place equipment shall not exceed 50 percent where lighting and convenience outlets are also supplied". On anything with a continuous load (3 hours or more) ampacity should be at least 125 percent of full load rating of the equipment.(like heat, air conditioning, motors, etc...) Please be careful.
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