Scott, Im not quite so sure.
If current flows back through the ground rather than neutral, that will trip the GFCI. The ground is BAD as far as the GFCI is, so the dryer cant be a 3-wire. The hypothetical situation was an Ungrounded hair dryer and plastic pipes (which would have to be totally dry no moisture). Then, current flow would be only back through neutral and, therefore, no pop. With any other slight variance and it would pop such as moisture from the faucet to the water line along the surface of the tub. . . . j o n a t h a n _____ From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Scott Reed Sent: Sunday, March 18, 2012 5:12 PM To: WISPA General List Subject: Re: [WISPA] Preventing stupid outages GFCI works by comparing the current on the hot side and the neutral side. If they are different by more than a very small amount, it trips. Even the static discharge from walking across the carpet and touch a protected device can create enough current on the neutral side to trip some devices. The water in the tub doesn't have to be ground if the hair dryer has a 3 wire cord. There can be current through the water to the dryer's ground, thus creating the imbalance needed to trip the device. The last time I read the NEC, you can string outlets off a GFCI outlet, up to a maximum of 4. After that you need another GFCI. On 3/17/2012 9:41 PM, Jonathan Schmidt wrote: GFCIs you cant live with them and cant live without them. A real problem is that they wear out something that isnt well known. Old GFCIs may pop prematurely or fail to pop. TEST THEM YEARLY! About the hair dryer in the bathtub assuming the water is ground, I cant imagine that exactly the same current from the hot side will 100% flow back on the neutral because, if it isnt, the thing will pop. What am I missing about the bridge and the sensitivity? I had my sister have all her old house sockets (at least the head of a string) equipped with GFCIs. I took a cheap tester to her house and almost 50% of the AC sockets were wired wrong so they needed fixing, too. Many had grounded outlets that had no ground, and ½ had the pins backwards! I guess the folks who sold them the house in 1985 did a band-aid job. If you have customers with older houses and old GFCIs supplying their modem/router, you should encourage them to test and replace before calling you. Anyway, every time my sister had a thunderstorm, the office GFCI would pop probably because the computer was grounded through the cable router and cable modem. The socket was behind a very large, heavy bookcase. Im proud of her, because, by the second time, she got a drill with a ¾ bit and put a hole in the backboard to allow pushing the reset with a pencil eraser. Hence, my recommendation to have your customers understand this since the GFCI that runs your service is the most likely to pop in a thunderstorm. . . . j o n a t h a n _____ From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Blair Davis Sent: Saturday, March 17, 2012 1:37 AM To: WISPA General List Subject: Re: [WISPA] Preventing stupid outages GFCI's are to detect and prevent leakage currents. They monitor the current in the hot and the neutral lines. Ever stood barefoot on the ground and held a drill or saw and gotten shocked? A GFCI, working properly, will prevent that from killing you, or even shocking you for more than a few mS In properly working equipment, basic electrical theory shows that the current in the hot line and current in the neutral lines must be equal. If the currents are not equal, then current is 'leaking;' out of the circuit. The GFCI senses the imbalance and interrupts the circuit to stop the leakage. They are not perfect, though. You can hook up an old 2 prong hair dryer and drop it in a bathtub full of water without tripping the GFCI if you know how. I was an electrician for the Navy for years... I won't plug a tower into one. Every time the lighting flashes for 30 miles around, they trip... On 3/16/2012 11:45 AM, DJ Anderson wrote: I thought GFCI's were to protect circuits from moisture mainly, AFAIK they do not provide any type of protection for devices other than cutting the circuit if it senses a ground fault. DJ Anderson Shelby Broadband On Fri, Mar 16, 2012 at 11:38 AM, Ben West <b...@gowasabi.net> wrote: To add to the anecdotal evidence against cheap GFCI outlets, I had to remove one in a building when spontaneous trips started occurring randomly (e.g. once every couple weeks) after an adjacent building received a direct lightening strike. For that matter, the GFCI contributed nothing to lightening protection, still lost a bunch of equipment. -- Ben West http://gowasabi.net b...@gowasabi.net _______________________________________________ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless _______________________________________________ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless -- West Michigan Wireless ISP Allegan, Michigan 49010 269-686-8648 A Division of: Camp Communication Services, INC _______________________________________________ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1913 / Virus Database: 2114/4876 - Release Date: 03/17/12 -- Scott Reed Owner NewWays Networking, LLC Wireless Networking Network Design, Installation and Administration Mikrotik Advanced Certified www.nwwnet.net (765) 855-1060 (765) 439-4253 (855) 231-6239
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