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Thread: Extending ungrounded circuit

  1. #1

    Default Extending ungrounded circuit

    I have question about a lighting circuit in my house. It is an older 2 wire 15 amp with no ground.
    I want to add one receptacle to this circuit to be located on the wall outside of the bathroom since I have everything in the bath opened up for a remodel. This circuit will also serve two light fixtures in the bath. We have a house that was originally built in the 50's, with no overabundance of outlets in the house, but over the years we have added them. I am not sure about this situation though. Is it ok to mix lighting and outlets; especially with no ground? It is the easy way to do it, but I want to do it right.
    It would be easy enough to add one from the bath circuit, but I am fairly certain that is a no go.
    How important is a ground on a lighting circuit? My living room has the same situation; is there anything inherently bad about no ground wire. What seems odd is that a new breaker was added in the panel for the bath, and when we checked the circuit for the living room, there is a ground wire at the panel.

    One more question, I think I know the answer, but here goes anyway--When extending a circuit thats wired with 14 gauge wire, is it ok to wire the extension with 12? (15 amp circuit)

  2. #2
    In the Trades Bob NH's Avatar
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    It is OK to add #12 wire to a 15 Amp circuit.

    It is also permissible to have receptacles and lighting fixtures on the same circuit.

    If I had to extend an ungrounded circuit I would find the first receptacle on the circuit and replace it with a GFCI receptacle, with the following part of the circuit connected to the load terminals of the GFCI receptacle.

    I would do the same thing on the bathroom receptacle circuit.

  3. #3
    Jack of all trades frenchie's Avatar
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    It is NOT okay to feed 12 gauge off of a 14 gauge circuit.
    Ever.
    Code-wise, or common-sense safety-wise.


    It is okay to mix lighting and receptacles.


    It is not okay, code-wise anyways, to extend a circuit, without bringing the whole thing up to code. Ungrounded circuits are only allowed because they're "grandfathered" - i.e., they were okay at the time they were put in. If you modify it, you have to upgrade it to current code. How else is the extension going to meet current code, which it has to since it's being done now?
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    Moderator & Master Plumber hj's Avatar
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    Default wires

    It is NOT okay to feed 12 gauge off of a 14 gauge circuit.
    Ever.

    Now you tell me. And here every house I have had for the past 30 years had all 12 gauge wires for every circuit, including 15 amp ones. So i guess you will have to tell me why it is "not okay". And be convincing.

  5. #5
    In the Trades Bob NH's Avatar
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    Quote Originally Posted by frenchie View Post
    It is NOT okay to feed 12 gauge off of a 14 gauge circuit.
    Ever.
    Code-wise, or common-sense safety-wise.


    It is okay to mix lighting and receptacles.


    It is not okay, code-wise anyways, to extend a circuit, without bringing the whole thing up to code. Ungrounded circuits are only allowed because they're "grandfathered" - i.e., they were okay at the time they were put in. If you modify it, you have to upgrade it to current code. How else is the extension going to meet current code, which it has to since it's being done now?
    Please cite the code paragraphs that prohibit extending a #14 (15 Amp) circuit with #12 wire, and that require that grandfathered ungrounded circuits be upgraded to existing code if modified as in by extending it.

    I suggest that 250.130 including 250.130(C) permits the extension without upgrading the whole circuit, and 406.3(D)(3) describes the approved method of adding a GFCI to a circuit without an equipment ground.

  6. #6
    Jack of all trades frenchie's Avatar
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    Red face

    I

    learn

    something

    new

    every

    day.



    ... I need to have a chat with my sparky, about creating un-necessary work for himself.
    Master Plumber Mark:

    there is nothing better than the
    manly smell of WD 40 in the air
    while banging away on brass with a chisel and hammer...

    it smells like......victory......

    do not hit your thumb...
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  7. #7
    Electrical Contractor/Instructor jwelectric's Avatar
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    Talking

    Quote Originally Posted by frenchie View Post
    I

    learn

    something

    new

    every

    day.
    And it takes a big to admit it.

    Notice that the chick is the little one here lol

  8. #8

    Default

    Quote Originally Posted by frenchie View Post
    It is NOT okay to feed 12 gauge off of a 14 gauge circuit.
    Ever.
    Code-wise, or common-sense safety-wise.
    True, 'common sense' may dictate not using #12 on a 15amp circuit, but it is not a Code violation. Yes, someone may, in the future, see the #12 wire and assume it's a 20amp circuit, but then they should read 90.1(C) and the definition of a "Qualified Person".
    Just my 2 worth.

  9. #9

    Exclamation

    Here in NYC it's a CODE REQUIREMENT that #12 be used on 15A circuits, lighting and otherwise; #14 on a 15A circuit will be red tagged. I still haven't found anyone - even NYC inspectors - that can tell me the logic for this.

  10. #10

    Default

    ok, so I guess that I can run the extension with 12 gauge, but code says that I have to put in a gfi outlet.

    Any comments on these--

    How important is a ground on a lighting circuit? My living room has the same situation; is there anything inherently bad about no ground wire. What seems odd is that a new breaker was added in the panel for the bath, and when we checked the circuit for the living room, there is a ground wire at the panel.

    Would the ground wires have not been used purposely?

    Thanks for all the answers the last couple weeks.

  11. #11
    In the Trades Bob NH's Avatar
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    The purpose of the ground wire (Equipment Grounding Conductor) connected to metal parts of the electrical system, and to equipment connected by a grounding plug, is to trip the circuit breaker if the grounded part is accidently energized; thereby protecting against fire hazards and protecting those who might contact that potentially energized part.

    The purpose of the Ground Fault Circuit Interrupter (GFCI) is to provide additional protection on high-risk circuits where a person has a higher risk of contacting a potentially energized piece of equipment (such as a hair dryer or washing machine) while touching another grounded piece of metal such as a faucet. The GFCI is supposed to trip at a low current (less than 0.006 Amp) that would not be fatal to a human.

    Absence of a ground is a lower risk in places where it is unlikely that a person will come in contact with an unintentionally energized metal part, such as in a ceiling-mounted lighting fixture.

    Absence of a ground and/or GFCI is a significant risk around a piece of equipment such as a washing machine, which has a lot of potential for being accidentally energized and is in the vicinity of a grounded faucet that can be reached by an operator of the equipment.

  12. #12
    Jack of all trades frenchie's Avatar
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    Just to clarify -

    I didn't think it was wrong to use 12 gauge on a 15 amp circuit - in fact, it's what I'm used to, since I'm in NYC where everything is 12ga.

    (Joe - FWIW - the rationale I was given, years ago, is that NYC apartments get a lot of illegal extensions added on, people overloading circuits by running new branch extensions, etc... so they like to have some margin of safety built-in. Begs the question, though: why aren't 20 amp circuits required to be 10 ga? and so on... In the end, like so much else in the city codes, the real answer is, "just because".)

    What I did think, was that you can't increase the size of the conductor, further along the circuit, from what you start with. Kinda like plumbing drain lines, where you can't go to a smaller pipe, further downstream?

    And I coulda sworn I'd read something, in some sparky discussion online somewhere... I guess the main lesson is that I'm no brainiac when I'm insomnia-posting.

    So I'll shut up now, lest I repeat the foot-mouth process, lol.


    Oh - the other thing - the gripe I thought I had with my sparky - was about the need to update the branch you're tapping into.

    But thinking about it... I don't think he ever said it was code-required. Just "this is the better way to go about it". Since we're usually dealing with open walls... it's probably just plain easier.
    Master Plumber Mark:

    there is nothing better than the
    manly smell of WD 40 in the air
    while banging away on brass with a chisel and hammer...

    it smells like......victory......

    do not hit your thumb...
    __________________
    Just so everyone's clear: I'm the POODLE in the picture ("french", get it?) The hot woman is my wife.

  13. #13
    Aspiring Old Fart, EE, computer & networking geek Mikey's Avatar
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    Quote Originally Posted by frenchie View Post
    Kinda like plumbing drain lines, where you can't go to a smaller pipe, further downstream?
    But you can go to a larger pipe, further downstream... 12ga is a larger electrical pipe... Oh, the harmony of it all!

  14. #14
    Jack of all trades frenchie's Avatar
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    yeah, but - oh, never mind.
    Master Plumber Mark:

    there is nothing better than the
    manly smell of WD 40 in the air
    while banging away on brass with a chisel and hammer...

    it smells like......victory......

    do not hit your thumb...
    __________________
    Just so everyone's clear: I'm the POODLE in the picture ("french", get it?) The hot woman is my wife.

  15. #15

    Default

    It is always OK to use larger wire, say #12 or #10 on a 15 amp circuit. It is NOT OK to use smaller wire.
    If you are adding new wire, "extending a circuit", you must use new 3 wire grounded cable, or wire in conduit and it must be grounded. You shall not connect new wiring to an old two wire system. GFCI protection does not change this rule.

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