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electric outlet for window AC question

Discussion in 'Electrical Engineering' started by ReadyToPuke, Jun 6, 2005.

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  1. ReadyToPuke

    ReadyToPuke Guest

    What's the going rate in central NJ for
    a licensed electrical contractor to upgrade
    the wiring from an old breaker panel (1960)
    to a wall outlet that would be powering a
    new 110 volt window mount air conditioner?

    I don't have the exact BTU capacity, but
    it's a standard 110v plug, and probably an
    existing 15 amp breaker.

    When I try to run the unit off the existing
    outlet (controlled by a light switch), the
    breaker trips immediately.

    I have not tried bypassing the light switch
    (since it's probably not rated for an AC
    compressor starting up).

    My thinking however was it would be safer to
    run new wire w/double the amperage capacity
    (say 30 amps), and put in a new breaker and
    feed the outlet directly w/all upgraded wire
    and no switch (other than the breaker).

    The home is a straightforward single level
    ranch structure, I was thinking of doing it
    myself, but it might be better to have a "pro"
    who's experienced, licensed, etc. do the job.

    What's a fair price a typical contractor would
    charge ?
     
  2. ReadyToPuke

    ReadyToPuke Guest


    Hello,

    Thanks for the post.

    The unit does work though, when I plug it in at a friends
    house (newer wiring), it fires up and runs fine.

    So that's why I was thinking just upgrade the wiring,
    put in a proper size breaker to match the AC unit, and
    bypass the light switch to feed the outlet directly.

    What's a fair price for a "pro" to do that sort of job?
     
  3. Anthony

    Anthony Guest

    @news.monmouth.com:

    You aren't going to get a price from here. Without looking at the house,
    how it is constructed, distance from the panel to the window in question,
    how many extra (if any) slots in the breaker panel, and many, many other
    factors, a price cannot be set.
    The methodology of the house contruction probably plays the biggest role
    in pricing. It may be as simple as using the existing wire to pull in a
    new feed, or it may be as complex as having to rip out the wall covering
    (drywall, paneling, etc) at both the outlet and the service panel to run
    the new wire.



    --
    Anthony

    You can't 'idiot proof' anything....every time you try, they just make
    better idiots.

    Remove sp to reply via email

    http://www.machines-cnc.net:81/
     
  4. Chris Lewis

    Chris Lewis Guest

    What's most likely happening is that 15A is adequate, but the circuit
    is either unduly long (and is 14ga), or has lousy connections, so
    the high load of an AC pulls down the voltage too far, the AC works
    too hard starting up, and the breaker gives up on it because the startup
    surge takes so long.

    Heck, the breaker may just be "tired".

    Large window mount ACs should have their own circuit.

    Usually, a 15A circuit will be fine, but if the circuit is
    longer than about 20-30', use 12ga for the circuit. If the
    breaker still trips, as long as you've used 12ga, switching
    to a 20A breaker is cheap.

    There's no way to estimate how much it should cost to do without
    seeing it.
     
  5. w_tom

    w_tom Guest

    Note what Chris posted. "... or has lousy connections
    ....". How well connected are wires inside wire nuts and wires
    attached to the switch and receptacle. Do they use the screws
    on side or do they just push in the back. Low voltage on
    startup (due to lousy connections or too long wire) results is
    excessive current draw during startup. Verify wires are fully
    twisted together inside wire nuts and that connections to
    switch and receptacle use side mount screws.

    How long is that wire from air conditioner to breaker box?
     
  6. Chris Lewis

    Chris Lewis Guest

    I thought I might add one person's experience:

    _Many_ years ago, my parents finally got around to installing a window
    mount AC. Early 70's house, 15A circuits. Probably only a 6000BTU unit,
    whereas 10K (and even some 12K) BTU units can work fine on 15A
    circuits.

    There's an outlet right underneath the window, on the end of a string
    of outlets in the dining room - only use of that circuit was for
    the dining room fixture. Simple.

    Turn on the AC - _nothing_ else on that circuit turned on. The thing
    would make noises for a minute or so struggling to turn on. Lights
    dim. This isn't good.

    Well, it's hot, we need the cool. We'll worry about another cirucit
    later.

    Whoops!

    Within an hour, all _three_ upstream outlets were smoking, blackened
    the outlet covers and stained the wall.

    The wires were correctly sized for 15A. The circuit wasn't particularly
    long. But the idjit who wired it used the push in terminals. And
    it was aluminum wire...

    [Push in terminals on Al has always been illegal. But 3 out of 3
    catching fire at the same time is pretty spectacular confirmation
    that pushins are bad, Al or not.]

    When installing an AC on non-dedicated circuits for the first time, DO NOT
    LEAVE IT UNATTENDED the first day. Check upstream outlets and switches
    for overheating.

    It's so much more comfortable having an AC on a dedicated circuit
    with a spec-grade (or better) outlet.
     
  7. I'll highlight every where that needs more specific information. I think it
    makes more sense to run 12 or 14, and breaker it with the proper sized
    breaker for the wire size.

    I also think that you need an electrician. We can't reasonably quote it over
    the internet.

    --

    Christopher A. Young
    Learn more about Jesus
    www.lds.org
    www.mormons.com




    What's the going rate in central NJ for
    a licensed electrical contractor to upgrade
    the wiring from an *old breaker panel (1960)*
    to a *wall outlet* that would be powering a
    new 110 volt window mount air conditioner?

    *I don't have the exact BTU capacity*, but
    it's a standard 110v plug, and *probably an
    existing 15 amp breaker*.

    When I try to run the unit off the existing
    outlet (controlled by a light switch), the
    breaker trips immediately.

    I have not tried bypassing the light switch
    (since it's probably not rated for an AC
    compressor starting up).

    My thinking however was it would be safer to
    run new wire w/double the amperage capacity
    (say 30 amps), and put in a new breaker and
    feed the outlet directly w/all upgraded wire
    and no switch (other than the breaker).

    The home is a straightforward single level
    ranch structure, I was thinking of doing it
    myself, but it might be better to have a "pro"
    who's experienced, licensed, etc. do the job.

    What's a fair price a typical contractor would
    charge ?
     
  8. About $50 for the tripcharge and $60 an hour. Plus parts. Though, I might be
    way too cheep.

    --

    Christopher A. Young
    Learn more about Jesus
    www.lds.org
    www.mormons.com




    Hello,

    Thanks for the post.

    The unit does work though, when I plug it in at a friends
    house (newer wiring), it fires up and runs fine.

    So that's why I was thinking just upgrade the wiring,
    put in a proper size breaker to match the AC unit, and
    bypass the light switch to feed the outlet directly.

    What's a fair price for a "pro" to do that sort of job?
     
  9. Roy Q.T.

    Roy Q.T. Guest

    From what I've read:
    I would check and see if it has 12 or 10 AWG [14 awg is out of the
    question for an AC {if that's the case you'll need to rewire the
    outlet},14Awg is best left for ligting circuits only] bypass the switch
    for a test (though not essential) and make sure the receptacle was rated
    and well connected., then I'd check the Breaker itself and make sure
    it's in good working order and that nothing else is on the circuit.

    If you were to rewire the AC wall outlet with 12 or 10 awg, it would
    take a home run from the panel [+-125$ cabling only] I'd use #12 or 10
    Armoured [BX] Cable and a receptacle & breaker rated for the AC unit.,
    It takes 15 Amps Protection (listed on the Plate on the sidefront of the
    ac) If cost is not too much a factor I'd definetly use # 10 with a 15
    Amp Breaker & a 20 Amp Receptacle (this works well for a future 20A more
    powerful unit as well) ., If the run from the panel is 12 Awg and in
    good insulated conditions I'd check for anomalies on that
    circuit,correct them and probably save you some expense...

    Not Estimating yet, But: A Ballpark Figure would be 200-300$ for a new
    dedicated circuit = depending on how much digging and terminating is
    required.

    Troubleshooting and Correcting 55$ -125$ depending on Time and Materials
    used.

    In NJ it's probably more on the + $ide.
    note: AC Mechanics do not do Electrical Troubleshooting or work on
    Residential Circuitry., I know I worked for GE door to door. ~Roy~
    E.E.Technician

    From: (ReadyToPuke)
    What's the going rate in central NJ for
    a licensed electrical contractor to upgrade the wiring from an old
    breaker panel (1960) to a wall outlet that would be powering a new 110
    volt window mount air conditioner?
    I don't have the exact BTU capacity, but it's a standard 110v plug, and
    probably an existing 15 amp breaker.
    When I try to run the unit off the existing outlet (controlled by a
    light switch), the breaker trips immediately.
    I have not tried bypassing the light switch (since it's probably not
    rated for an AC compressor starting up).
    My thinking however was it would be safer to run new wire w/double the
    amperage capacity (say 30 amps), and put in a new breaker and feed the
    outlet directly w/all upgraded wire and no switch (other than the
    breaker).
    The home is a straightforward single level ranch structure, I was
    thinking of doing it myself, but it might be better to have a "pro"
    who's experienced, licensed, etc. do the job.
    What's a fair price a typical contractor would charge ?

    <~/
     
  10. w_tom

    w_tom Guest

    One can use a 20 amp receptacle on a circuit powered from a
    15 amp breaker? Obviously it is safe. But is that code
    legal?
     
  11. w_tom

    w_tom Guest

    Appears to be a minor discrepancy between HorneTD and
    phil-news-nospam. I agree that nuisance tripping can have
    safety consequences. If the NEMA rating for that receptacle
    is 20 amps, then one should expect up to 20 amps from that
    receptacle.

    However, is this discrepancy between both posters created by
    a code change, or just by different wording that says same
    thing?
     
  12. Guest

    Look at 210.21(B)(3) again. The top line says 15a circuits shall have
    receptacles "not over 15a"
     
  13. Roy Q.T.

    Roy Q.T. Guest

    From:
    On 8 Jun 2005 04:21:48 GMT,
    wrote:
    It could just be that I can't find the part of the code that says a 15
    amp circuit cannot have a 20 amp receptacle

    Look at 210.21(B)(3) again. The top line says 15a circuits shall have
    receptacles "not over 15a"

    ~>Exactly: I do know why Phil argues anything to the contrary., I even
    explained what could physically happen to a 15A receptacle on a @20A
    circuit. ®oy
     
  14. Guest


    Phil look at TABLE 210.21(B)(3) NEC every year since the FDR
    administration.
     
  15. John Gilmer

    John Gilmer Guest

    The odds are that it will be about the same as what you paid for the air
    conditioner.

    I note that Walmart sells 240 units when you get to the 10,000 BTU/hour
    size. If you have room for another two pole breaker in you box, it may be
    about the same charge from the electrician and you may be happier with a
    larger a/c.
    If you run a new circuit, the electrician likely would want to connect it to
    a new breaker.
    Likely, that's a 15 amp "lighting" circuit. Find an unswitched wall
    outlet. You CAN use a heavy duty extension cord. See if it still "trips."
    You can save some money.

    As I said, if you are starting from "scratch" then consider going to a 240
    unit.
     
  16. Al

    Al Guest

    For all it's worth, in Massachusetts its about $5/amp. So a 200 amp
    service panel is one grand.

    Al
     
  17. John Gilmer

    John Gilmer Guest

    Well, you can compensate for that by running the A/C on "LOW." Most
    machines will really pump out the moisture then.

    I know the conventional "wisdom" is better slightly too small than too big.
    But when you have a HOT day and you A/C is too small, you might as well just
    open the windows.
     
  18. Roy Q.T.

    Roy Q.T. Guest

    Argue all you want, FireMouth Tom: I'll reply as I can, if you don't
    like it, fine, but don't Misdirect the public or tell me what to do nor
    how to do it.....I never thought i'd say this but go jump on a Candy
    Apple Red Truck and leave this alone.

    FACT IS: 15A receptacles should be used on 15A circuits and if you
    think nothin of it put it on a 20A circuit., The Danger is not only in
    overloading a 15A circuit with a 20A load but having a perfect 20A
    circuit with a 15A receptacle can cause a fire Maybe not today or
    tomorrow but in the long run, when others forget it's not rated and plug
    in an overload. be it as may be, they are not the same physically., AND
    as per the NEC - 20A receptacles are allowed on a 15 Amp circuits
    whether you like it or not., it is safe at the user or end level, Now
    **** Off !

    & The Hell with This Post it's way overdone....®
     
  19. John Gilmer

    John Gilmer Guest

    Well, the "right" size determination uses ASSUMPTIONS about the outside
    temperature and the heat load. Combine an extra hot and humid day with
    having a few folks over or just arriving back home after a day or two of
    your home being "heat soaked" and your conventional wisdom becomes nonsense.

    The problem with running a room conditioner at low is that the outside coil
    doesn't get as much circulation but it sure does suck the water out of the
    air.

    To each his own, but if you have the electrric power and the spare cash when
    you buy a window unit, go for a larger size. "Efficiency" just ain't all
    that important if all you are cooling is ONE room. >
     
  20. John Gilmer

    John Gilmer Guest

    Because its when it's hot as hell outside that you want an A/C that can
    keep you cool.

    It's "nice" the have an A/C that "pumps" the exact amount of heat AND you
    can pay to get a variable capacity central unit. If you have a window
    unit, you can reduce capacity by lowering the fan speed, by putting a heater
    in the room (this used to be standard in "computer rooms" where it was
    essential to keep the RH within a certain range), or by permitting a little
    circulation to the remainder of the house. But during those HOT days, that
    "extra" capacity is a blessing.
    Big deal. Turn on the ceiling fan. It will mix the air and even had a
    few watts of heat load. And it's fun to watch. Problem solved.
    You are being silly. If you have a fixed capacity window unit you can size
    it to be "too big" all the time (and play games with fan speed to adjust
    capacity) or get a unit that's too small some of the time and be downright
    miserable. I will gladly sacrifice a few "perfect" days to avoid a single
    "miserable" day
     
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