Will a Gfci breaker solve my problem?

Discussion in 'Remodel Forum & Blog' started by beetz12, Dec 5, 2010.

  1. beetz12

    beetz12 New Member

    Messages:
    9
    Location:
    columbia
    Hi guys,

    I just recently purchased a 50-year old house in which all the receptacles in the living room are ungrounded. Since that's where I have my TVs and computers, I'd like to make sure they are protected in the event of a lightning strike.

    Today a building contractor suggested installing a GFIC breaker in the main breaker box, the logic being that if the lightning strikes, the breaker box is the initial point of entry and when the breaker trips, all my electronics will turn off before any damage occurs. Is his logic correct?

    Thanks in advance for everyone's input!
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,896
    Location:
    New England
    Don't think that will help. You can install a whole-house surge suppressor in the main panel, though. The higher the number of joules it can absorb and the faster it switches the better. Typically, you need two open slots as many specify installation on a dedicated breaker (you need one for each leg). A good stand-alone surge suppressor would help, but most rely on the ground connection to function at their max, and the only way to get that is to rewire. You CAN install a gfci breaker or receptable and install grounded outlets after it, but the ground is still not there and available to dump current from a near-by strike - it wil provide safety from a product defect, though.

    Note, if the house is prone to lightning strikes, you may want to install lightning rods (some houses, due to their elevation or surrounding structures or ground material are very prone to attract lightning strikes).
  3. beetz12

    beetz12 New Member

    Messages:
    9
    Location:
    columbia
    Hi Jim,

    Thanks for your quick and thorough reply. If I'm understanding you correctly, you're saying that even with a GFIC breaker I still need to run a ground wire run to each receptacle to provide protection against lightning. Is that right?

    If the answer to the above is yes, are there any benefits to installing a GFIC breaker? Would it be better if I install a whole-house surge suppressor instead if all I'm trying to do is protect my electronics?

    Thanks again
    David
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,896
    Location:
    New England
    Most better surge suppressors utilize the ground to bleed off the excess current. If you don't have one, it isn't as effective as if it had one. A gfci is a human safety device...it protects YOU if the device has a current leak and it tries to find a path though you rather than back through the neutral. It might trip if there was a surge, but it might not. The best solution is to rewire for equipment safety. Keep in mind a direct lightning strike will probably destroy stuff regardless, with good surge suppressors, it can often survive nearby ones. Most of them won't honor their warranty unless installed on a grounded circuit from those I've looked at. Code does allow a grounded outlet to be installed on a gfci protected circuit without a ground if you mark them as no equipment ground - gfci protected. It makes it easier to plug in anything, but certain devices, surge suppressors in particular, won't be as effective and some will give you an error signal indicating a ground fault without a real ground.
  5. beetz12

    beetz12 New Member

    Messages:
    9
    Location:
    columbia
    Jim, thanks again for the great answer. It sounds to me that rewiring the entire house is my best option. My contractor obviously got a couple of facts wrong - I'm extremely glad I learned the truth from you before I wasted a bunch of time and money.
  6. Thatguy

    Thatguy Homeowner

    Messages:
    1,460
    Location:
    MD
    Contact power companies online in FL for the size you need. I don't have the bookmark any longer but the unit that they would install for subscribers had a 10 year design lifetime. FL has a lot of lightning strikes.
    The energy absorbing capacity is measured in thousands of joules and I've noticed that plug-in surge suppressors weasel-word around saying how many joules they can absorb.
    Suppressors are tested to a "standard lightning strike waveform". It's tens of thousands of peak amps and peak volts.
    There's one version in fig. 1 of the link below
    http://www.weighing-systems.com/TechnologyCentre/Lightning1.pdf

    Because of the uncertainty as to what your suppressor will have to absorb, included in the suppressor price is insurance on your stuff, possibly up to 5 kilobucks.

    BTW, GFCIs trip in milliseconds, electronic equipment is damaged in microseconds.
    Last edited: Dec 7, 2010
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