Old house grounding issues

Discussion in 'Pro Audio' started by Aaron Kentucky, Feb 12, 2004.

  1. I recently moved to a house built in '52 and discovered that all the
    outlets in my studio/bedroom are two prong and with no ground (not
    even conduit) running between the receptacles - I tested continuity
    with a meter. At first I was concerned with noise issues, but now I
    am more concerned with safety. I build simple synths modules and have
    open ps circuits around (and sometimes a beer or two.) Rewiring is
    not an option because I am renting.

    I have read through many of the posts and the best I can come up with
    for safety is to install a GFI with no external ground at the wall and
    run everything through that one outlet with daisy chained power
    strips. Is this the best I can do?

    As far as noise goes... would it help at all to plug my
    computer/periphs into a different outlet (same house circuit?) Is it
    completely wacky and absurd to run a #12 wire from the equipment
    ground (unused 3rd prong on power strip) out my window and ram it into
    the ground with some magic rod or attach it to a cold water pipe?

    Thanks,
    aaron
     
    Aaron Kentucky, Feb 12, 2004
    #1
    1. Advertisements

  2. Aaron Kentucky

    Mike Cleaver Guest

    It's always best to check with your local electrical code or a
    licensed electrician.
    The ground fault receptacle could work. Make sure the hot and neutral
    wires go to the correct terminals but make sure to connect the ground
    lug on the GFI receptacle to a cold water pipe.
    Then plug in your power bars and make sure all your audio gear plugs
    into those.
    Unless you're running massive amps, the current draw shouldn't be a
    problem.

    ..On 11 Feb 2004 23:59:01 -0800, (Aaron Kentucky)
    wrote:
    Mike Cleaver Broadcast Services
    Voice-overs, Newscaster, Engineering and Consulting
    Vancouver, BC, Canada
     
    Mike Cleaver, Feb 12, 2004
    #2
    1. Advertisements

  3. Aaron Kentucky

    R. Foote Guest

    No, GFI's must be grounded. Hence the name. (actually GFCI or ground
    fault current interrupter)


    You could theoretically do that, although it wouldn't be code. The
    best thing to do is have an electrician put in a proper ground rod at
    the panel and run a new circuit in conduit through the wall and hook
    it up to a new outlet in a surface mount box.
     
    R. Foote, Feb 12, 2004
    #3
  4. Aaron Kentucky

    Mike Tulley Guest

    No. The GFI outlet won't do any good without a ground.

    Get a GFI breaker and install it in the breaker box, with a proper
    ground. Run the two wire oulet from the GFI breaker. That will reduce
    your risk of ending your audio career by electrocution.

    Your audio equipment still needs a ground to control noise and RF
    interference. If your plumbing is as old as your wiring, you may be
    able to find a good ground at a cold water pipe.

    If your wiring is so old that it has a fuse box and you can't install
    a GFI breaker, or you don't have access to the breaker box, there MAY
    be something you can do with a two-wire circuit, a GFI outlet, and a
    water pipe ground. It won't meet code, but it might be better than
    what you've got. Find an understanding electrician to put it together
    for you.

    Mike T.
     
    Mike Tulley, Feb 12, 2004
    #4
  5. Aaron Kentucky

    Dale Farmer Guest

    What I would do, rather than screwing around with any of the existing
    wiring is to hire an electrician to run a new wire from the fuse box with
    two well grounded 20 amp circuits. Plug everything audio related into
    those outlets and use the previous outlets for lights and the humidifier.
    Cost of this ought to run from a hundred bucks to over a grand,
    depending on how much hassle the cable run is, and how much other
    work needs to be done to bring the building electrical ground system
    up to current electrical code.
    Based on the questions you are asking, you know just enough to
    be very dangerous, and the most likely victim is you. Don't try to do
    this yourself please.

    --Dale
     
    Dale Farmer, Feb 12, 2004
    #5
  6. Aaron Kentucky

    Scott Dorsey Guest

    Yes it will, and it also meets the code under article 215-9. The GFI outlet
    measures the differential current between the neutral and hot wires. If
    there is any leakage to ground, more current will flow through one than
    the other, and the GFI will pop. No ground is required.
    This will also work just as well, BUT of course you need a modern breaker
    panel. If your house is equipped with Edison fuses, you're out of luck.
    This is NOT CODE. The cold water pipe ground exists ONLY to keep the
    water system at ground potential. You MUST HAVE a proper grounding system
    to the panel or you are in big violation, and also not operating safely.

    If you have an outlet with a ground, you MUST have a line to the panel
    where it connects to the main building ground point (usually a single rod).
    Otherwise you are in violation of the code, and also looking for some real
    noise problems too (since your ground and neutral are no longer bonded).
    The two wire circuit with a GFI is code. But, you still need a good
    three-wire line to the panel for your audio gear.
    --scott
     
    Scott Dorsey, Feb 12, 2004
    #6
  7. Aaron Kentucky

    S O'Neill Guest

    Actually, it will. GFIs have a small current transformer that encloses both
    white and black conductors, and will trip even if the fault current isn't going
    back into their own ground prong. It's the current imbalance between the black
    and white wires that causes a trip.

    However, The test button won't work since there's no way for it to unbalance the
    current without the green wire.
     
    S O'Neill, Feb 12, 2004
    #7
  8. Aaron Kentucky

    Mike Tulley Guest

    Thanks for the correction. Because the test button didn't work, I
    thought that it could no longer sense a fault current.

    Mike T.
     
    Mike Tulley, Feb 12, 2004
    #8
  9. Aaron Kentucky

    Mike Rivers Guest

    Nope, they don't, which is why they can be used to protect old wiring
    without a separate ground. They sense the current on both the hot and
    neutral wires, and opens the circuit if there's any difference between
    the current in the two wires. The assumption is that some of the
    current from the hot wire is taking a detour back to the source, most
    likely through something (you, for example) conducting it to ground.
    That's a ground fault, hence the name.



    --
    I'm really Mike Rivers ()
    However, until the spam goes away or Hell freezes over,
    lots of IP addresses are blocked from this system. If
    you e-mail me and it bounces, use your secret decoder ring
    and reach me here: double-m-eleven-double-zero at yahoo
     
    Mike Rivers, Feb 12, 2004
    #9
  10. This seems to be the consensus after reading other posts on the topic.
    Would you recommend running everything through the one GFI outlet? I
    assume it doesn't matter current-wise since they are all on the same
    breaker anyway, but does it help/hurt to separate the audio floating
    ground from the computer's floating ground?

    I did find a grounded outlet in the living room so when I make some
    recordings that matter I can run a 20ft extension cord to power
    everything.

    Thanks,
    aaron
     
    Aaron Kentucky, Feb 13, 2004
    #10
  11. Aaron Kentucky

    Mike Rivers Guest

    No. But you should get a proper grounded box run to your studio. A
    real, licensed electrician should do it, and it probalby won't take
    more than an hour or so. Less than $200 including wire and materials.
    That's a temporary work-around, but if it's the only grounded outlet
    in the house, unless it's a new installation (as many of us have
    recommended for your studio) it may not be a very good ground. It's
    legal in most places to install a grounded outlet in a box that's
    wired with BX (the flexible steel armored cable) and tie the ground
    terminal of the outlet to the metal box, which is attached to the BX
    armor with a screw. That may be a legal electrical ground for safety
    purposes, but BX isn't a good enough conductor to act as a good ground
    for EMI.



    --
    I'm really Mike Rivers ()
    However, until the spam goes away or Hell freezes over,
    lots of IP addresses are blocked from this system. If
    you e-mail me and it bounces, use your secret decoder ring
    and reach me here: double-m-eleven-double-zero at yahoo
     
    Mike Rivers, Feb 13, 2004
    #11
  12. Aaron Kentucky

    R. Foote Guest

    Thanks Mike, but just because it *will* work improperly wired doesn't
    mean it is right.... Wiring ANY power circuits without a ground,
    regardless of the situation is just plain stupid!
     
    R. Foote, Feb 13, 2004
    #12
  13. Aaron Kentucky

    Mike Rivers Guest

    Not only is it stupid, but it's against electrical code for new
    wiring.

    However, using a GFI outlet on a circuit without a ground wire is not
    only legal, but serves a valuable purpose, which is not the same as
    the safety ground on a grounded outlet- it keeps you from getting
    electrocuted if you somehow manage to touch the hot wire and you're
    grounded well enough so that even a little current can flow through
    you.

    The safety ground works in a different way. If the hot wire somehow
    finds its way to a grounded chassis (frayed insulation, a shorted
    capacitor, or whatever), rather than the chassis becoming hot and
    allowing you to complete the circuit to ground when you touch it, the
    safety ground forms a path between the hot and neutral through the
    ground wire, and hopefully the fuse or circuit breaker will trip
    before the wiring heats up and sets the house on fire. But even if the
    circuit breaker doesn't trip, while you're waiting for the house to
    burn down, if you touch the chassis, very little current will flow
    through you because you're not nearly as good a conductor as the
    ground wire. (Which is why you should never disconnect the safety
    ground - because you're a lot better electrical conductor than air.)


    --
    I'm really Mike Rivers ()
    However, until the spam goes away or Hell freezes over,
    lots of IP addresses are blocked from this system. If
    you e-mail me and it bounces, use your secret decoder ring
    and reach me here: double-m-eleven-double-zero at yahoo
     
    Mike Rivers, Feb 13, 2004
    #13
  14. I installed the GFI and the test button actually does work without the
    ground.

    I also noticed that the old outlets were wired backward. I installed
    the new GFI correctly, but will this cause a problem with the rest of
    the circuit?

    When I test the outlets with a little yellow test plug both ways it
    says each is fine. Perhaps it can't tell without the ground...? Is
    there a way to test the line wires to make sure *they* aren't
    backward?

    I realize this is getting slightly off-topic, but I do respect the
    opinions in this matter of those who are audio oriented.

    Thanks,
    aaron
     
    Aaron Kentucky, Feb 14, 2004
    #14
  15. Aaron Kentucky

    R. Foote Guest

    Yes, but you basically only use a GFI near water (laundry room,
    kitchen bath) or outdoors. I don't think anyone is using GFI's
    anywhere else... This might be valuable as a temporary fix, but
    running a new circuit is what the original poster should be looking
    at.

    Aesthetically, you could use "Wiremold/Plugmold" to dress things up in
    the event you need to run the new circuit on an exposed surface. Looks
    good and is fairly inexpensive compared to opening walls. All the
    electrical pro's I work with really only want to use GFI's where they
    are absolutely necessary, since they tend to go defective. On one job
    where we installed 30+ GFI's on a multi building remodel, we had 2
    that were defective out of the box.

    If a GFI fails, the ground wire will be the only protection you have
    if the utility neutral fails, which happens a lot, due to improper
    crimping above the meter. If that path to "ground" fails, you are SOL
    with or without a GFI.

    Something else to note, I don't know one contractor who would wire a
    GFI without a ground regardless of whether it was code in an old
    building with possible hidden wiring faults. Electrical work is just
    not that expensive. I have "re-wired" small older houses by running
    EMT outside and punching through existing outlet boxes in a couple of
    hours longer than it takes to replace all the outlets, including a new
    meter base/ load center. The owners ALWAYS understood the tradeoff
    between aesthetics and sfety, and not once have I seen a property
    owner want to "cheap out" in this area, especially when the property
    is a rental.

    Run a new circuit, don't screw around with band aid solutions.

    My 2 cents.
     
    R. Foote, Feb 15, 2004
    #15
  16. Aaron Kentucky

    Mike Rivers Guest

    True, you usually find GFI outlets in bathrooms or kitchens, not in
    living rooms, but you get the same protection no matter where you
    install the outlet.
    You can't eliminate every possibility of getting electrocuted, but you
    can help prevent stupid people from hurting themselves in common
    situations. I haven't really thought about it very hard, but I'll bet
    that a GFI would trip in the situation where you have one hand on your
    electric guitar strings, touch a mic stand with the other hand, and
    get a shock.
    I have an outside light on a post (well at the moment I don't because
    it got knocked down) and it's fed from a buried piece of lead-sheathed
    flexible cable, two conductors, no ground wire. I installed a GFI
    outlet on that post because it was a handy place to plug in a weed
    whacker and hedge trimmer. Although those tools are double-insulated
    and don't have a safety ground on the plug, I just felt better about
    putting in the "legal" GFE outlet rather than putting in a standard
    grounded-looking outlet with no ground. And I wasn't about to dig up
    the yard and run a ground wire back to the main breaker box just for
    that outlet in the yard.



    --
    I'm really Mike Rivers - ()
    However, until the spam goes away or Hell freezes over,
    lots of IP addresses are blocked from this system. If
    you e-mail me and it bounces, use your secret decoder ring
    and reach me here: double-m-eleven-double-zero at yahoo
     
    Mike Rivers, Feb 16, 2004
    #16
  17. Aaron Kentucky

    R. Foote Guest

    Good points... One thing I have seen is connecting the gnd terminal to
    the neutral when replacing 2 wire outlets with 3 wire outlets. Don't
    know if it is code, but I have seen it done.
     
    R. Foote, Feb 17, 2004
    #17
  18. Aaron Kentucky

    Mike Rivers Guest

    Certainly not according to code, though it might fake out a tester,
    and might prevent electrocution. If there was a short between the hot
    side and chassis of a device plugged into such an outlet, it would
    essentially short across the line, tripping the circuit breaker or
    blowing the fuse.


    --
    I'm really Mike Rivers ()
    However, until the spam goes away or Hell freezes over,
    lots of IP addresses are blocked from this system. If
    you e-mail me and it bounces, use your secret decoder ring
    and reach me here: double-m-eleven-double-zero at yahoo
     
    Mike Rivers, Feb 17, 2004
    #18
  19. Aaron Kentucky

    S O'Neill Guest

    I did this once, the wiring got messed up upstream after I did it and white and
    black got reversed (wasn't me that time), making everything with a third prong
    hot, including any exposed metal. Not one of my brighter ideas. :-/
     
    S O'Neill, Feb 17, 2004
    #19
  20. Aaron Kentucky

    Dobbie Guest

    not the most professional looking page but I'm pretty sick at the
    moment and want to go to bed

    http://www.faqs.org/faqs/electrical-wiring/part1/section-33.html

    But, it is correct.. if you want to know why then look up a page on
    how GFCIs work and you'll see that at minimum they protect themselves
    regardless of whether or not they have a ground connected

    anyone who says different needs to go take a couple EE courses
     
    Dobbie, Feb 18, 2004
    #20
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.