In the never ending saga of things I have not yet seen, we had a 350 kcml 3 phase underground feeder burn out yesterday at our AM transmitter site.
Actually, it happened the day before, around noon. I received a call from the remote control that we were on the backup generator. Upon arriving at the site, I found several trees down on the three phase primary down the street. I figured that was the cause. After checking the generator fuel supply, oil pressure, temperature, phase volts/amps, I decided that everything was okay and the power company would be along shortly to restore power. I then continued up the road to our FM site to do weekly maintenance.
Upon returning to the office several hours later, I looked at the utility company website. They have a pretty cool interactive map application that shows all outages and give restoration times. The area around our transmitter site showed no outages, therefore I figured it had been cleared.
I committed two errors here:
- Not calling the utility company myself to ensure that the outage was reported. I assumed that the tree across the three phase primary was the cause, it was not.
- Not calling the transmitter site remote control to check the generator status after I checked the website.
To be honest, I don’t know if I am coming or going these days. With seven radio stations, each with it’s own transmitter site, three of them Directional AM stations, and three studio locations spread out over a 75 mile stretch, it is difficult to keep up with the small details. Did I mention that I am solo, the engineering assistant position was cut two years ago. But, I am not here to make excuses…
The net result is the generator ran all night long. The next day, when I checked the transmitter in the morning, I was surprised to find the generator still running. Unfortunately, I had an FM station on low power (see post below) that needed to be taken care of first. When I finished replacing the RF module in the FM transmitter, I made my way to the AM site.
I called the power company then checked the generator fuel, the propane tank was down to 10%. Yikes, better get this taken care of fast. I will say the power company showed up pretty quickly. After some measurements with a hand held meter, it was determined that the under ground feeder was open between the pole and the transmitter building.
The line man was not at all surprized, in fact, he called it before he even went up in the bucket truck. After some back and forth with his supervisor, who came out in a pick up truck, it was decided that they would run a temporary overhead feed to the meter can.
They also did some research in there records and discovered that they (the utility company) own the underground cable and therefore they would dig it up and fix it. That’s nice because otherwise it seems like it would be an expensive repair job. On a station that makes not a lot of money.
3 thoughts on “Underground Electrical feeder burn out”
Most utilities are cheap and use aluminum underground conductors which are more prone to corrosion. And most of the time they are laid in a trench without a complete sand layer covering. For radio stations, aerial feeds are probably more reliable in the long run and easier to fix if a casualty should occur.
I prefer using the under ground cabling, I know that it’s more expensive but it last longer if placed very well with soft sand layer on it with out any small stones, and if we consider the correct current for this cable, it will maintenance, and I’m responsible , but when doing a connection under ground it’s another thing
it will be maintenance free i mean