GFCI Outlet Questions

Discussion in 'Electrical Forum discussion & Blog' started by kailor, Feb 9, 2011.

  1. kailor

    kailor New Member

    Messages:
    22
    Location:
    Huntsville, Alabama
    I'm remodeling a Mobile Home (MH) and have a couple of GFCI outlet questions.

    Q1: After locating the outlet at the BEGINNING of outlets wired in series, and finding the LINE for the beginning outlet coming from the circuit panel, if the breaker feeding the LINE is a 15A breaker, that means each plug in the series should be a 15A outlet, correct?

    Q2: When installing new outlets, would it be harmful to install 20A outlets, leaving the 15A breaker in the circuit panel, or should I also put in a 20A breaker in the circuit panel to feed the circuit, or should I just install 15A outlets to match the 15A breaker in the circuit panel (assuming 15A would adequately service the kitchen/bathroom plugs)?

    Q3: Which brand name of GFCI receptacles is the safest and best to get from a big box store?
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,801
    Location:
    New England
    While you can have 15A receptacles on a 20A circuit, you CANNOT put a 20A receptacle on a 15A circuit. Whether you can swap the circuit breaker to 20A would be determined by the wire gauge size. It must be at least 12g wire to swap it to a 20A CB. It's probably 14g. Can't help you with brands. Not all GFCI have a load output, so some cannot be used to protect those downstream.
  3. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Most GFI you will find readily are labeled 15 amp, ( 20 amp feedthrough). This is OK to be on a 15 amp breaker, as the only load which can be plugged in to any of them is a 15 amp load. But don't put in a 20 amp GFI ( it will have one blade vertical, and the other blade T-shaped.)
  4. drick

    drick In the Trades

    Messages:
    392
    Yes and it probably is. 20A GFCIs are more $$$.

    You cannot change out the breaker. The breaker protects the wiring and is sized for the wiring in your home. 15A GFCIs are what is commonly installed in residential construction even if the breaker is rated 20A. If you install 20A GFCIs you won't hurt anything, but you will be throwing away your money as they are more expensive.

    Sorry, can't help here. I only shop those stores if I am desperate and I remembered to bring a paper bag to wear over my head:D That said I don't know of a brand that has a bad rep for GFCIs at the moment.

    -rick
  5. Jeff1

    Jeff1 New Member

    Messages:
    102
    Location:
    So Cal
    What is the reasoning used for this? I'm just trying to understand what code/physics is trying to protect us from. Thanks
  6. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    This is so that you do not plug 20 amp corded devices into a 15 amp circuit that is not rated to handle the current.

    Even a 15 amp slotted device will still be rated for 20 amp feed-thru.
    Last edited: Feb 10, 2011
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,801
    Location:
    New England
    The aggragate (sum) of the load could be 20A if the wiring supported it, but no individual load could exceed 15A if you restrict the use of receptacles to 15A (20A feed-through) on a 20A circuit. But, one 20A load would exceed the capacity of a 15A branch circuit, so why would you allow one to be plugged in by using a 20A receptacle? A device rated to exceed 15A requires a special plug, and preventing that from happening, is the reason. You could have numerous lower wattage devices plugged into one circuit, and thus desire a 20A branch, but not want any one device to hog all the power. Typically, a heavy user warrants a dedicated circuit.
  8. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,236
    Location:
    Land of Cheese
    Another good reason is that there is nothing in the average residence that uses a 20 amp plug and thus would require a 20 amp receptacle. The one exception I can think are a few of the bigger window or through-wall mounted air conditioners, but even most of them are 220V.
  9. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    All kitchens in our zone must have 2 dedicated countertop 20 amp circuits with 20 amp receptacles.

    http://www.buyacehardware.com/cooper-wiring-industrial-decorator-receptacle-3164696.html

    http://www.buyacehardware.com/ace-safelock-gfci-receptacle-3192531.html
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,801
    Location:
    New England
    Unless they've modified the national code, they must be GFCI-protected 20A circuits, 20A pass-through receptacles, but the receptacles themselves only need to be 15A.
  11. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    This is correct
  12. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Kitchen counter level outlets, yes GFCI.

    So the code allows 15 amp receptacles on a 20 amp breaker? Is that so you can see how plastic melts and throws out smoke? Good code!
  13. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,236
    Location:
    Land of Cheese
    Ballvalve, I don't believe your thinking is clear.

    A 15 amp receptacle will only allow a 15 amp plug to be plugged into it. A 20 amp receptacle will allow a 15 or 20 amp plug to be plugged into it. There is no other difference between the receptacles.

    [​IMG]
    20 amp plug
  14. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    Code does not let us daisychain kitchen counter outlets. In fact, we have to split each outlet and feed it with two breakers.
  15. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,236
    Location:
    Land of Cheese
    Note that LLigetfa is in Canada, which for obvious reasons does not fall under the U.S. code.
  16. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,801
    Location:
    New England
    Also, note that the receptacle must be rated to pass 20A on the terminals if used for feed-through. It would seem Canada's code is a lot more strict in this sense, maybe expecting lots of loads simulaneously. While not a bad thing, maybe a bit overly conservative...it certainly would prevent some issues, but at a cost most people won't need. Most appliance manufacturers recommend that you run a dedicated circuit for their high-current devices, and if you do this, you'd normally not have a problem.
  17. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Before commenting on my thinking you should think to understand what a 20 amp outlet really looks like for a kitchen

    http://www.buyacehardware.com/ace-safelock-gfci-receptacle-3192531.html

    Takes a standard plug. Gee, thats why they make up 20 amp circuits on 12 gauge wire.
    Last edited: Feb 12, 2011
  18. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,236
    Location:
    Land of Cheese
    Yes, look at the 20 amp GFCI receptacle and then realize that it is capable of plugging in the 20 amp plug which I posted a picture of.

    With the exception a plug-in air conditioner, I have yet to see anything in anyone's home that required a 20 amp receptacle.

    All the cords on anything commonly found in a house have a 15 amp plug, as that meets or exceeds the current draw of the device being powered.
    Last edited: Feb 12, 2011
  19. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    Ja, I filled in the Location: info so no mystery there and I was careful to use the term "us" as in us Canadians. Note that ballvalve is in California and he cites a similar code.
  20. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Toaster and microwave.

    Countertop oven and warming plate.

    iron and a hot plate. I could continue.

    Those receptacle things have [2] spots for plugs. Women do funny things in the kitchen.

    15 amp receptacles are rated for 15 amps continuous draw only. I use 20 amp receptacles as often as possible because they have better internals and grip a plug tightly.
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