HI;
**I could really use some help from the experianced folks on this one, as the liceansed electrician was just lost in terms of knowing what wires are safe** Thanks in advance.
This is a true story about what happened to my dad and his house last night when working in his panel. This shows just how dangerous working around unfused service conductors is, even with your panel off. My dad is very lucky that there was no arc flash of any size. No one was injured, luckly, but it could have easily been a very different story.
My dad was trying to trace some circuits in his panel, with the main pulled. I don't know exactly how it happened, I wasn't in the basement at the time. Thank god he was using one of my klien insulated tools. He someone had a #4 awg bare wire that was connected to the water meter contact a unfused service conductor. This energized every metal part in the house. It melted through the clamp on the water meter cutting a hole in the pipe, flooding the basement.
I suspect that the circuits on other leg of the panel, not the one he made contact with became energized with 240V +/- any resistance from items on these lines.
As soon as I realized he had energized everything metal in the house, and wires were smoking and melting, I demanded he get away from the house and I would not even let him pull the meter because everything was energized. Calls to 911 and to the power co for an emergency dc at the pole were made.
It took the power co almost an house to dc at the pole and remove the meter. The entire time wires were melting and smoking. A number of the romex wires in the basement had the insulation melt and drip off the wires.
After the power co came and the fire dept cleared the house as safe, and the water got shut off at the streetWith power off at the pole ; I tested contunity between the neutral and hots. 4 or 5 of the circuits had continuity.
A liceansed electrican was called and came out. He grounded the system, to a old rod (one that was never connected to the electrical system) and rebonded to what was left of the water pipe. He did not replace the SE cable or anything else. He then had the power co restore power. I have all the breakers off, except for 2, where I put new wire in for the furnace and a utitilty outlet at the panel.
I asked the electrician, about how we can know if any of the wires in the house are safe or useable. I asked him about meggering he knew what it was but didn't have access to the equiptment to do it.
I know much is going to have to be rewired. This is a house from around 1917, very hard to fish wire in.
My question here is, If some of the branch circuits appear to look good physically, and I test the continuity on the wires with a sensetive meter, would that tell us the wire is safe to use? My concern is that the insulation may still be partially melted through, and there is a arcing hazard later on when there is a load on the branch circuit. Would Meggering actually tell us if they were safe to use?
The liceansed electrican just didn't know, and he was going to just turn on all of the branch ciruits that were not dead shorting. I was not comfortable with that at all, and I turn off everything, but the 2 circuits I did with fresh wire.
Do you think there is any chance of using any of the old wire safely? Do you think that the wires that were on the leg of the panel that got grounded out would be more likely to be ok, since they were not fed 240?
What would you guys do in this situation. It is a large 3,000sqft old house, very difficult to fish wires in. I bet this is going to be 10,000-20,000$ if the whole house needs a rewire due to the complexity of the wire fishing.
Any thoughts are greatly appriciated.
AGAIN FOR THE RECORD, AS I KEEP TELLING PEOPLE; UNFUSED SERVICE CONDUCTORS ARE VERY DANGEROUS, STAY AWAY FROM THEM IF YOU DON'T FULLY UNDERSTAND WHAT YOUR DOING!!!
Thanks guys,
Jamie
**I could really use some help from the experianced folks on this one, as the liceansed electrician was just lost in terms of knowing what wires are safe** Thanks in advance.
This is a true story about what happened to my dad and his house last night when working in his panel. This shows just how dangerous working around unfused service conductors is, even with your panel off. My dad is very lucky that there was no arc flash of any size. No one was injured, luckly, but it could have easily been a very different story.
My dad was trying to trace some circuits in his panel, with the main pulled. I don't know exactly how it happened, I wasn't in the basement at the time. Thank god he was using one of my klien insulated tools. He someone had a #4 awg bare wire that was connected to the water meter contact a unfused service conductor. This energized every metal part in the house. It melted through the clamp on the water meter cutting a hole in the pipe, flooding the basement.
I suspect that the circuits on other leg of the panel, not the one he made contact with became energized with 240V +/- any resistance from items on these lines.
As soon as I realized he had energized everything metal in the house, and wires were smoking and melting, I demanded he get away from the house and I would not even let him pull the meter because everything was energized. Calls to 911 and to the power co for an emergency dc at the pole were made.
It took the power co almost an house to dc at the pole and remove the meter. The entire time wires were melting and smoking. A number of the romex wires in the basement had the insulation melt and drip off the wires.
After the power co came and the fire dept cleared the house as safe, and the water got shut off at the streetWith power off at the pole ; I tested contunity between the neutral and hots. 4 or 5 of the circuits had continuity.
A liceansed electrican was called and came out. He grounded the system, to a old rod (one that was never connected to the electrical system) and rebonded to what was left of the water pipe. He did not replace the SE cable or anything else. He then had the power co restore power. I have all the breakers off, except for 2, where I put new wire in for the furnace and a utitilty outlet at the panel.
I asked the electrician, about how we can know if any of the wires in the house are safe or useable. I asked him about meggering he knew what it was but didn't have access to the equiptment to do it.
I know much is going to have to be rewired. This is a house from around 1917, very hard to fish wire in.
My question here is, If some of the branch circuits appear to look good physically, and I test the continuity on the wires with a sensetive meter, would that tell us the wire is safe to use? My concern is that the insulation may still be partially melted through, and there is a arcing hazard later on when there is a load on the branch circuit. Would Meggering actually tell us if they were safe to use?
The liceansed electrican just didn't know, and he was going to just turn on all of the branch ciruits that were not dead shorting. I was not comfortable with that at all, and I turn off everything, but the 2 circuits I did with fresh wire.
Do you think there is any chance of using any of the old wire safely? Do you think that the wires that were on the leg of the panel that got grounded out would be more likely to be ok, since they were not fed 240?
What would you guys do in this situation. It is a large 3,000sqft old house, very difficult to fish wires in. I bet this is going to be 10,000-20,000$ if the whole house needs a rewire due to the complexity of the wire fishing.
Any thoughts are greatly appriciated.
AGAIN FOR THE RECORD, AS I KEEP TELLING PEOPLE; UNFUSED SERVICE CONDUCTORS ARE VERY DANGEROUS, STAY AWAY FROM THEM IF YOU DON'T FULLY UNDERSTAND WHAT YOUR DOING!!!
Thanks guys,
Jamie