- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
This was what I found when a customer called and asked if I could temporarily fix/replace a fuse so they could restore power to get heat.
I had to break it to them that there was no "temp fix," I would have to replace the panel. There was a lot of insulation damage inside and so much soot that I couldn't tell one wire color from the other. The fuse block that burnt was for the water heater. After replacing the panel and repairing/replacing some of the wires, I checked the water heater. I expected to see burnt marks on it with a missing ground. But everything was good at the WH, connections good, ground in place. There was a disconnect there as well, all was good there too.
I'm pretty sure the fuse block was either worn or not seated properly causing a high resistance that led to the damage.
Here's the strange part. I called a POCO lineman to see who could come and disconnect power so that I could replace the fuse panel. He asked me the address and when I told him he said that he was just there a day before. Now the customer says no one from the POCO had been called nor did they come out. I told the lineman that and he said that he was there to check a reported outage in the area. He found a fuse blown at the transformer. He said he wondered why it blew but decided it might have just been an old fuse so he replaced it. Luckily the customer had the 200A main fuse block pulled or the damage would have been worse once the trans. fuse was replaced.
I didn't check the main fuses to see if they had blown but wished I had. I was just trying to get the power back on because of the cold. If the fuses were good, I wonder why the trans. fuse blew and not the mains? Even if the mains blew, that should have kept the trans. fuse from blowing. But who knows how much fault current went through before something blew.
I had to break it to them that there was no "temp fix," I would have to replace the panel. There was a lot of insulation damage inside and so much soot that I couldn't tell one wire color from the other. The fuse block that burnt was for the water heater. After replacing the panel and repairing/replacing some of the wires, I checked the water heater. I expected to see burnt marks on it with a missing ground. But everything was good at the WH, connections good, ground in place. There was a disconnect there as well, all was good there too.
I'm pretty sure the fuse block was either worn or not seated properly causing a high resistance that led to the damage.
Here's the strange part. I called a POCO lineman to see who could come and disconnect power so that I could replace the fuse panel. He asked me the address and when I told him he said that he was just there a day before. Now the customer says no one from the POCO had been called nor did they come out. I told the lineman that and he said that he was there to check a reported outage in the area. He found a fuse blown at the transformer. He said he wondered why it blew but decided it might have just been an old fuse so he replaced it. Luckily the customer had the 200A main fuse block pulled or the damage would have been worse once the trans. fuse was replaced.
I didn't check the main fuses to see if they had blown but wished I had. I was just trying to get the power back on because of the cold. If the fuses were good, I wonder why the trans. fuse blew and not the mains? Even if the mains blew, that should have kept the trans. fuse from blowing. But who knows how much fault current went through before something blew.