jwnagy
Member
- Location
- Damascus, Maryland
I went on a service call a few days ago in response to a homeowner reporting dimming lights, appliances shutting down, and surge protectors burning up.
What I found is perhaps the most extreme case of failed service conductors I have seen in the 30years I have been an electrician, due to shoddy workmanship done in 1983 (the date of the final inspection per the inspection sticker).
When I arrived, I found things exactly as described to me. These are townhomes that are fed from the street to a 1200 amp service cabinet, with a 6-meter stack bussed on each side. The main disconnect (150 amp, Cutler Hammer type CC) for the dwellings are next to the meters, so the feeders to each individual home are sub-feeders. The wires were contained in a 2" PVC conduit at both the panel and the meter stack.
I noted that as the refrigerator cycled on and off, the lights on other circuits on the first floor would dim, while others got very bright, with a corresponding drop in voltage in a number of receptacles at the same time. Unplugging the clothes dryer resulted in the lights going out in the kitchen and the small appliance circuit for the refrigerator going out as well.
The first thing I checked was to make sure then right size wire was used and in the right combination. The neutral bar was isolated from the ground, fed with the correct size insulated wire, and there were no jumpers from neutral to ground. A #4 wire was run from the main water service to the ground bar and a separate, insulated ground conductor was run from the main service to the sub-panel.
My "wiggy showed somthing was a-miss when I attempted to check voltage avialiblity. I changed over to my Fuke 75 and found these readings:
"A" Phase to Neutral - 187 volts
"B" Phase to neutral - 61 volts
I shut down all of the branch circuit breakers and then turned them back on one breaker at a time while monitoring the voltages:
"A" phase to ground varied anywhere from 138 to 155 volts, and "B" phase also varied about the same, depending on what breakers were being turned on.
I took a voltage reading from Neutral to Ground and found 22 volts.
I shut down the main breaker outside and all of the branch circuit breakers inside and checked continuity between ground and neutral in the sub-panel. I had no continuity until I turned a branch circuit breaker on. I checked continuity at the main, in the meter stack, and found continuity.
At this point I informed the homeowner that the neutral and the ground wire feeding the panel (sub-panel) in their townhome had been compromised. I dug down under the meter stack to see if the conduit going to the townhome had been broken due to settling of the foundation and/or footers. What I found was that the conduit was just a sleeve and that 10" below grade were direct burial single conductors going down and presumably going under the slab (homes built without basements) to the panel in thier house. I then found two direct burial cables cut just below.
Sometime in the past, before the present homeowners bought 10 years ago, the cables feeding the home were damaged. I was able to determine that the damaged cables were the ungrounded conductors ("A" and "B" phase) and that instead of running all new feeders, they cut off the damaged wires, abandoning them in the ground, and then ran new phase wires around the house (couldn't go under the slab) and re-fed the panel. The neutral and ground were retained as they were, going under the slab, while the new "A" and "B" wires were run a different direction and are much longer.
So what we have is:
To top it off, the replaced conductors are only under 8" under the ground, no protection. There are so many code violations involved in this, it boggles the mind.
The result has been the loss of almost every major appliance in the house, including a large TV and all portable phones.
This afternoon we are running a temporary feed to the panel, until the homeowner can hash out how he will pay for this after hashing it out with his insurer.
The lesson for all of you guys out there just getting into the trade is that youmay think you've gotten away with something hinky, but it does come back to hount someone. In this instance, the owner is fortunate his home didn't burn.
Jeff Nagy
Master Electrician, State of Maryland
What I found is perhaps the most extreme case of failed service conductors I have seen in the 30years I have been an electrician, due to shoddy workmanship done in 1983 (the date of the final inspection per the inspection sticker).
When I arrived, I found things exactly as described to me. These are townhomes that are fed from the street to a 1200 amp service cabinet, with a 6-meter stack bussed on each side. The main disconnect (150 amp, Cutler Hammer type CC) for the dwellings are next to the meters, so the feeders to each individual home are sub-feeders. The wires were contained in a 2" PVC conduit at both the panel and the meter stack.
I noted that as the refrigerator cycled on and off, the lights on other circuits on the first floor would dim, while others got very bright, with a corresponding drop in voltage in a number of receptacles at the same time. Unplugging the clothes dryer resulted in the lights going out in the kitchen and the small appliance circuit for the refrigerator going out as well.
The first thing I checked was to make sure then right size wire was used and in the right combination. The neutral bar was isolated from the ground, fed with the correct size insulated wire, and there were no jumpers from neutral to ground. A #4 wire was run from the main water service to the ground bar and a separate, insulated ground conductor was run from the main service to the sub-panel.
My "wiggy showed somthing was a-miss when I attempted to check voltage avialiblity. I changed over to my Fuke 75 and found these readings:
"A" Phase to Neutral - 187 volts
"B" Phase to neutral - 61 volts
I shut down all of the branch circuit breakers and then turned them back on one breaker at a time while monitoring the voltages:
"A" phase to ground varied anywhere from 138 to 155 volts, and "B" phase also varied about the same, depending on what breakers were being turned on.
I took a voltage reading from Neutral to Ground and found 22 volts.
I shut down the main breaker outside and all of the branch circuit breakers inside and checked continuity between ground and neutral in the sub-panel. I had no continuity until I turned a branch circuit breaker on. I checked continuity at the main, in the meter stack, and found continuity.
At this point I informed the homeowner that the neutral and the ground wire feeding the panel (sub-panel) in their townhome had been compromised. I dug down under the meter stack to see if the conduit going to the townhome had been broken due to settling of the foundation and/or footers. What I found was that the conduit was just a sleeve and that 10" below grade were direct burial single conductors going down and presumably going under the slab (homes built without basements) to the panel in thier house. I then found two direct burial cables cut just below.
Sometime in the past, before the present homeowners bought 10 years ago, the cables feeding the home were damaged. I was able to determine that the damaged cables were the ungrounded conductors ("A" and "B" phase) and that instead of running all new feeders, they cut off the damaged wires, abandoning them in the ground, and then ran new phase wires around the house (couldn't go under the slab) and re-fed the panel. The neutral and ground were retained as they were, going under the slab, while the new "A" and "B" wires were run a different direction and are much longer.
So what we have is:
To top it off, the replaced conductors are only under 8" under the ground, no protection. There are so many code violations involved in this, it boggles the mind.
The result has been the loss of almost every major appliance in the house, including a large TV and all portable phones.
This afternoon we are running a temporary feed to the panel, until the homeowner can hash out how he will pay for this after hashing it out with his insurer.
The lesson for all of you guys out there just getting into the trade is that youmay think you've gotten away with something hinky, but it does come back to hount someone. In this instance, the owner is fortunate his home didn't burn.
Jeff Nagy
Master Electrician, State of Maryland
