This bizarre show happened twice at my house. The first time it happened I only realized something was at fault when I was having to call the cable company every two weeks to fix the cable internet. One time a technician came back and said the connections were burned up at the pole and as soon as he managed to unplug it... sparkles.

I plugged a lamp between neutral and ground, and there was light. I called in a horrible electrician at the time that simply disconnected ground from the affected region of the house, the garage.

Recently it happened again, an outlet from the washing machine overheated because the dryer was extending that outlet straight from it, no pigtail. The plastic overheated and melted some of the cable's coating and once again ground was live and the TV coax too!

I'm mature enough to understand the poor piece of work done, fixing, inspecting things now, not trusting any electrician, but I'm having trouble investigating the odd ground behavior.

Why did the TV send out power from the live ground :( instead of it going to earth? Not a single breaker ever went off. I'm no longer connected to the street's TV service. Satellite and fiber now. I'm not sure what would ground things now. Has anyone seen such thing?


closed as off-topic by Leon Heller, Dave Tweed May 29 '14 at 16:19

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    \$\begingroup\$ Unfortunately this question isn't really on-topic, as it's not about electronics design. I think you just need to find a reputable, qualified electrician to come and sort out the issues. There's no way to provide a reasonable answer in the context of this site, as nobody here has access to your household wiring to perform some basic measurements and inspection. \$\endgroup\$ – JYelton May 29 '14 at 15:58
  • \$\begingroup\$ Better fit on diy.stackexchange.com \$\endgroup\$ – Adam Lawrence May 29 '14 at 16:03
  • \$\begingroup\$ Somewhere you have an outlet, perhaps the TV where hot and neutral are reversed and or you have more than 10% line drop on Neutral. Neutral is only grounded at the transformer. But house ground is tied to copper plumbing or ground rod. Some old TV's have no galvanic isolation and depend on Neutral being near ground voltage. Yours is not. Trace the Neutral voltage back to the faulty wiring with a modest load connected and measure with respect to earth ground. \$\endgroup\$ – user43594 May 29 '14 at 23:48
  • \$\begingroup\$ I'll investigate neutral-ground voltage with the meter, wiring order and get back to you. \$\endgroup\$ – user43691 May 30 '14 at 0:07

I can't answer for Brazil, but in the US, the electrical system is required to be grounded at two places: at the pole transformer and again at the service entrance on each house. Everywhere else, neutral and ground are kept separate.

The cable TV system is also grounded at the service entrance; usually the cable installer simply runs a wire from their "box" (containing lightning arrester, filters, etc.) to either the power meter socket on the outside of the house, or the main breaker panel inside the house.

It sounds like you have a couple of things going on. First, it seems that your electrical system is not grounded at all, so look for the ground stake and check the connections between it and your main breaker panel.

Second, it seems that you have at least one line-to-neutral fault (short circuit) somewhere in your house, either in the wiring or in some appliance. Try to narrow it down by shutting off breakers and/or unplugging appliances in various groups or individually.

Get yourself a decent mains-rated multimeter and check for voltage between neutral and ground at various points; higher voltage will suggest that you are near the fault. Better yet, a clamp-on ammeter will allow you to monitor ground current directly. Worst-case, shut off all of the branch circuit breakers and then turn them on one at a time, looking for problems.

  • \$\begingroup\$ Thanks for the reply Dave. I remember seeing a rather thin ground wire coming from the street and connected to a metal part of the panel, and one thick ground cable coming from the house and going straight down through a duct. I'll investigate with the multimeter. I purchased the one you mentioned. \$\endgroup\$ – user43691 May 30 '14 at 0:02