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Electrical service entry wiring (SEC) damage or wiring errors:
Damaged or improperly sized, connected, supported or protected electrical service entry cables, whether overhead, along a building, or buried underground, can pose very serious shock, electrocution, or fire hazards for people and buildings, as these case histories and electrical service problem diagnosis reports illustrate.
This article series discusses procedures for safe and effective visual inspection of residential electrical systems including electrical panels and other components, when the inspection is conducted by trained building inspection professionals, home inspectors, electrical inspectors, and electricians.
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This article includes field reports of electrical system symptoms traced to unsafe electrical service wiring. We discuss and illustrate how these unsafe conditions might be observed or discovered and we describe what the electrician or other expert found that was causing the unsafe condition.
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2016/09/07 Licensed Electrician PA wrote: Here are pictures from 801 West Mill Street Gallatin, MO 64640
City worker (with no professional license or accreditation) connected Insufficient size of wire from power line to my meter box (after I stated NEC code requirements calling for minimum of 2/0 CU), of which I did follow and have running from my electrical Panel to the Meter box. City side of meter box shows 1 of the 2 city legs overheated, melted the insulation from the line, blew transformer on the pole, line in meter box arced to my building ground severing it from the 2 8' grounding rods and then fused/bonded the power line in directly to my bare copper ground running inside to Panel box and residence.
This electrified the entire home. You can see the visible arc marks throughout interior and exterior of home: Metal doors and frames, exterior siding and trim, outlets and outlet covers, furnace/air handler, caught one door and door frame on fire, shorted out all appliances in the home, Overheated wiring throughout walls and entire electric system.
Home was occupied at the time by 15 month old girl, her 8 month pregnant 22 year old mother, and the husband/father (me). Why this is not published on the front page of every national news paper? The family did not die and immediate action was taken by the very qualified home owner, (yours truly) and a very gracious Lord and Savior.
See attached Pictures.
I get home, of which I recently upgraded to 200 Amp service. Same township. I ran three 2/0 stranded copper lines (2 legs and a neutral) with #1 bare copper ground.
The city of Gallatin, Missouri had their electric guys come out (none of which are Electricians or even lineman). They ran #4 THWN FROM THE POLE TO THE METER. Where it connected through the meter to my 2/0 CU.
My 3 phase tankless pulls 112 amps alone. Well we had the Washer and Clothes dryer running, dishwasher, and were filling the 72 Gallon Jacuzzi tub (all 3 phases engaged creating a total load of 163 amps) last night.
We climbed in to the tub (my wife and I) and she opened the switch for the 25 amp Jacuzzi motor. [Are your arm hairs standing up yet??]
The insulation on the city side wiring melted, arced to the ground cutting it in half and bonding one of the legs with my bare ground wire which is now severed from from the 2 8' grounding rods and bonded un fused with my Ground!
Still producing fatal levels of electricity. My outlet covers are ornate metallic ones - yup electrified.
Above: as the local electrical grounding conductor system was made live by the short of SEC power cable to ground, arcing and overheating occurred at this electrical box. The arcing was between the lighting fixture's thin multi-stranded copper ground, tied to a grounding screw and the side of the box (lower red arrow).
The upper red arrow points to additional arcing between the fixture mounting clamp and the screw that connected the clamp to the electrical box. In the photo we see one ground screw connected to the fixture mounting brackt. I don't see but there might have been a second ground screw connected directly to the electrical box but I suspect there was not. If the box was not grounded to the grounding conductor except perhaps through the fixture bracket, and if the box was also grounded to earth through the home's metal siding, that might explain the arcing between the fixture bracket and the screw at the upper arrow.- Ed.
[Shown below] Metal staple conducts live current to metal siding. Note the electrical arcing burns along metal siding J-channel in the second photo.
Below: electrical arcing marks on the back side of metal siding.
Below: metal siding becomes electrically live and invites a building fire as well as shocked occupants.
Unaware of what has happened we were sitting in 70 Gallons of Hot water still filling from the 120 amp tankless hot water heater [shown above].
I don't quite know how we didn't die. I have some Intense photographs of the Meter box wiring you'd like to see. [Below]
Shown above: damaged SEC wiring in the electric meter pan after melted shorted power company SEC wiring.
When the electrical utility company's wiring is directly feeding a building's metal components, piping, grounding system etc., then there is no overcurrent protection for people at the building - the next "fuse" is a very high voltage device upstream in the utility company's wiring, perhaps at the nearest electrical power transformer.
A more common SEC damage case that has been reported more than once by readers occurs when someone drives a fencepost, perhaps a metal one for a chain link fence installation, into the ground such that it nicks or cuts an underground electrical service entry or other feeder wire. One reader reported getting shocked when touching the metal fencing.
As you agreed we will write post this discussion as a warning that might help save someone else from a fatality. at SAFETY for ELECTRICAL INSPECTORS we include a photo of a fellow who was literally cooked when he was trying to steal power by snipping a power line.
There we also illustrate other cases of SEC damage such as frayed lost insulation and water leaks into the electrical panel. See CORROSION in ELECTRICAL PANELS.
I wonder what your city authorities have to say about this near-fatality. They ought to be scared, really scared, since the same fellows who worked on your installation have doubtless installed quite a few others.
OPINION: Yes, most certainly we need to write this up and post it anywhere and everywhere it would be helpful. I believe the city of Gallatin should be forced to have Licensed Inspectors Examine every home on the grid. They should be held accountable for endangering my family especially my 8 1/2 month pregnant wife and 15 month old daughter. I am a bit beyond furious right now.
Above is a picture of the fried terminal. Pictures of 801 West Mill Street. Electrified Ground. Electrified Everything metallic in the home directly to the power line.
Below is a photo of arcing burn damage to neutral wires in the electrical panel.
Above: damaged neutral wires in the electrical panel following the SEC short to ground described in this field report from Gallatin Missouri.
2016/09/06 DCI P.A. wrote [by private email]
I am hoping to get some suggestions. I power cleaned a drain and felt mild electrocution in my hands. I further discovered the ground from the outlet in the home had current.
I flipped the main breaker and ground still has current as does the panel box itself. The city has an old wiring system where neutral is ran back through the power line. Ground to neutral is not allowed. Home has 200 amp service ran through 2/0 stranded copper SEC. However city line is aluminum half as thick. Main transformer blew power to the block when I started pulling close to full 200 amps.
What do I do?
If the main breaker in your electrical panel does not turn OFF the current that you are detecting, then
Watch out: At this building and based on what you describe, there are risks of electrical shock, death by electrocution or a building fire. If a licensed electrician cannot immediately find and fix the problem, in my OPINION and trying to keep you safe when all the information I have is a brief e-text, I have to advise that the building is unsafe to occupy.
In that event you'd empty the building of people and until the problem is found and fixed, you'd keep people away from the building and call emergency services as well as calling your power company immediately.
I am recently licensed April/2016. I am just dealing with a brand new one here. No current at ground outside, breaker on main is switched off which does kill power to building. However I still detect current from panel cover. I will do a little more investigation and let you know.
If you're an electrician working on a client's building, beware of the liability involved here and if you have any reason to think there are safety hazards, take immediate and appropriate precautions to keep people away - just sayin'
The problem was a tear in the SEC insulAtion and water in the conduit.
One of the two 110 legs had a small tear in the insulation, the conduit was not properly sealed and water entered the conduit (unable to drain due to the application of can foam insulation “used to keep the bugs out”. Water partially filled the base of the conduit allowing the ground to also become a conductor.
I tested the service panel access door at 118 VOLTS AND about 10,000 WATTS ! Lucky nobody got hurt. Thanks again for your invaluable time.
Really good going. These experiences are better training than most schools and classes. I've had similar reports to yours, for example when a chain link fencepost was driven down nicking the underground SEC - touching the fence was shocking.
As it will be helpful to other readers, and as its publication may prompt other readers to offer a helpful suggestion, I will include a redacted (to respect your privacy) version of this discussion online.
Watch out: for safety, also review SAFETY HAZARDS & SAFE ELECTRICAL INSPECTION PROCEDURES for Inspectors examining Residential Electrical Systems
You'd like to know about my nearly touching a sawn-off SEC on an older home during an inspection. The new overhead SEC was in clear view going to a new service drop to the street and a new cable down the wall to a new panel and a new box inside - I'd not been inside yet.
I stood by the corner pointing to the old obsolete meter box below which an old SEC had been sawn off with a hacksaw. I was pointing to it saying - here's the old, disconnected cable that went indoors to the old panel - my hand reached towards the bare copper ends of the sawn-off cable to touch the end as I continued to explain. The bare wire ends had no visible connection to anything relating to the new SEC. But it disappeared into the wall - maybe 15 feet from the new panel.
At the last moment some little voice said - Oh wait a minute. - I checked. it was live. I was live too - thanks to that hesitation.
That voice that saved your life just saved mine again. Unbelievable, simply unbelievable. Read my last message. I have electrified SEC without connection.
Last night I noticed flickering in my lights that are tied to the disconnected SEC! The Electrical depart. administration official for the city is the one who connected the neutral from the lpower line to my box AGAIN LAST NIGHT. Is this normal on dead/line?
I still have current right NOW at my service panel. The city upgraded the wiring to 4/0 aluminum. This is the old 2400 Delta System. Neutral CANNOT be bonded to ground.
Well these non-credentialed, unqualified city Employed Electrical Personnel HAVE tried to do my family and I in again. I notice my house is hot. at least 15° F hotter than outside. I have a heat source but no power or gas to the home.
I noticed city workers in my yard trying to read my meter. I don't have one. I told them my SEC was potentially compromised and not to be touched, connected, bonded or fused to ANYTHING.
We'll these geniuses have connected Neutral directly from the Pole to my old SEC Neutral. I test continuity between ALL THE FOLLOWING in my OLD SEC. Both my legs, neutral, AND ground. I have current still at my electric panel, according to fluke thermal imaging The ground is hot between my grounding rods and the pole.
I bet the city came out trying to find the source of a substantial power loss. I bet that Power they are looking for is what has heated my house substantially and the earth between pole and ground rods.
Thus is the current circumstance as I write.
OPINION: Provided you are totally confident that you're not making a mistake on your end by how you're observing or measuring electrical hazards, then ...
if this were my home at this point I'd get everyone out and call emergency services, and perhaps also a local newspaper and TV. It is awfully regrettable to have to to say so, but it may be that you need to embarrass the electric utility company into sending out someone who knows what the hell they are doing.
I'd also be worried that neighbors may be affected.
Noticed two hots AND Neutral. Above left & right: voltage on the SEC hot wires. Below: 88 volts on the SEC neutral wires.
I figured the bare ground that originally got bonded to leg , overheated and melted insulation on the 2/0 cu. Entire SEC BONDED. THEN city Elecectric admin. CONNECTED TO CITY 2400 Delta. I have juice in my box. I called city yesterday, they told me it's not an emergency and will check it out Monday if they have time!
If I found what I believed was an unsafe condition threatening life and safety and the utiltiy company said "not to worry" I would put the notice in writing and be very clear about the hazard of concern. That can prompt action.
PS: you have made sure, of course, that there are no problems in the panel or in local house wiring that would explain the problem, right? Like power is on and one or more circuits are actively using power - a condition that will give a return current on the neutral. Right?
Continue reading at LOST ELECTRICAL GROUND or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
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