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  1. #1
    Join Date
    Mar 2009
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    5

    Default Replacing Two Prong Outlets

    Any idea what the cost might be to replace two prong outlets in a house built in 1955 in the greater Boston area? There is a newer circuit breaker, but none of the outlets have been changed.

  2. #2
    Join Date
    Jan 2009
    Location
    Needham, MA
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    559

    Default Re: Replacing Two Prong Outlets

    cost for the materials, probably about $10-$30 depending on how many you have.

    cost for an electrician around boston, about $75-$95 per hour, figure on 3 hours to do an average house.

    cost for the advice on TOH Discussions....priceless

  3. #3
    Join Date
    Mar 2009
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    5

    Default Re: Replacing Two Prong Outlets

    would this cost take into account running ground wires to the box if need be? Or if there is a grounded box, can the new plug be grounded to the box?

  4. #4
    Join Date
    May 2008
    Location
    Baltimore, MD
    Posts
    76

    Default Re: Replacing Two Prong Outlets

    My house was built in 1956 and it was wired with an older type of Romex that did include a ground. I believe all of the boxes were grounded but the outlets were the old 2 prong ones.

    I did not change the outlets, I believe the realtor hired someone to do so before I bought it. But so far everyone I checked (which is most) has a pigtail to the ground wire. Unfortunately they used the stab connectors for the hot and neutral instead of the screw connectors and I had to re-do most of them not long after moving in.

    So to answer your question, if the house was wired with grounded Romex, grounding the outlets will likely not add to your cost. If new ground wires need to be run the cost could add up quickly depending on your home.

  5. #5
    Join Date
    Aug 2007
    Location
    The Great White North
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    4,045

    Default Re: Replacing Two Prong Outlets

    Depneding on the existing wiring you might check with your local building authority as to the electrical requirments.

    For example .... around here if the wiring is only 2 conductor ungrounded then it is not allowed to simply change the 2 slot receptacles with 3 slot ones without either ....

    running a seperate ground conductor from the panel throught the circuit to each fixture

    or

    running new 3 conductor from the service panel to each circuit

    or

    installing a GFCI receptacle at the beginning of each circuit and feeding each following receptacle labeling as ungrounded GFCI protected

    or

    installing a GFCI breaker feeding the circuit and labeling receptacles as ungrounded GFCI protected.


    Just a thought.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  6. #6
    Join Date
    Apr 2008
    Location
    Birmingham, AL
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    0

    Default Re: Replacing Two Prong Outlets

    I am not a licensed electrician but I ask a lot of questions and think things through before doing anything I'm not sure about. I was helping my father-in-law upgrade some wiring in his 1950's home. After examining what was there I asked a few electricians and got responses to my idea ranging from "that wouldn't pass inspection" to "that's just how I'd do it."

    This idea might not apply to your situation and codes vary somewhat, but here's something that might help.

    In my specific situation, a run of outlets was originally wired with 12-2 (no ground) Romex that ran under the house and went up into the wall through a hole in the bottom plate and attached to the outlet. A second piece of Romex attached to that outlet, went back down through the same hole, and continued on in the same manner to the next outlet. This pattern was repeated until the end of the run. In order to provide grounding I started with a home run to the panel with 12-2 with ground. At each point where the wires led up to an outlet I attached a circular work box to contain my new connections. I cut the 2 old wires (up & down) and pulled them into the work box. After identifying and marking which old 12-2 was which, I clipped off one black wire and wrapped the white wire (in the same sheath) with green tape. I did the same clipping and marking top-side as well. I joined the back, white, and newly marked green to the new home run 12-2 with ground and to a new piece of 12-2 with ground leading to the next work box. Then I repeated the process down the line. The result was a run of grounded outlets that, while it might not be EXACTLY to code, actually exceeded code in one respect. Whereas a hot, neutral, and bare ground are supposed to be in the same common sheath, this system actually has an insulated ground one gauge larger than normally required.

    A couple of cautions—
    Be sure to match gauge—don’t use a home run of 12 gauge and a 20 amp breaker if the existing wires you’re reusing are 14 gauge on a 15 amp breaker.
    Be sure to identify wires carefully. I don’t think you want to have a hot and a ground in the same sheath and the neutral running separately.

    Maybe that’s enough to spark some thoughts on your end.

    Eddie
    Last edited by install4you; 04-11-2009 at 12:32 AM. Reason: Correct error

  7. #7

    Default Re: Replacing Two Prong Outlets

    Even if there seems to be a path to ground for bonding it might be undersized, early cables such as AC when a wire or bonding ribbon was first added it was often undersized. You've said nothing about metalic boxes or other and nothing about the wiring type method so no one could say. Even earlier AC/BX might have been bonded to the concentric armor making the path more than 3 times longer than the circuit conductors. Older Romex had similar issues.

    Back in 1956 multiple paths to the plumbing pipes for ground common this was up to the 80s or 90s. Now only one connection is allowed and that is within the first five feet where the main enters the house.

    An insufficient path to ground can prevent a circuit breaker from opening when needed.

    Have an electrician check out the system including checking the main earthing connection and the bonding between other rods with a megger.

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