Well I defer to others on my utility pole transformer and the squirrels and the what I called "breaker" - fuse, sharing what happened and when the utility serviceman came out and my casual conversations with him.
Yes - when power did go off there was a loud "boom", at least a few times I heard it but other times asleep or not around.
There were a few times he just swung it back up after a visual inspection, other times he did get a new one, I was not around every time for the service call.
Knock on wood, it's been about 2 years since we've lost power due to the "squirrel factor", maybe they evolved and learned ?
sidebar: My dogs go bonkers when they see squirrels, it's a hoot when I let them out and they chase them off our property... it's like the movie Up!, seriously.
>>The underground dogfence does work, were on 2.2 acres, they don't cross it, as posted here it also works indoors for me
Originally Posted by sam_adams
That's not how it is constructed or works.
A line dropout high voltage expulsion fuse cartridge contains a fusible element, a spring-loaded arc rod, and a deionizing compound. When the fusible element melts because of a fault condition, the spring-loaded arc rod is released and draws the arc, formed by the melting fuse element, up through a cylindrical shaped compressed, powdered, deionizing compound. The deionizing compund is hydrated boric acid.
The boric acid decomposes from the heat of the arc into water vapor (steam) and boric acid anhydride quenching the arc and breaking the circuit. The decomposition of the boric acid into steam results in a high pressure condition inside the fuse cartridge. The high pressure steam blows out the exhaust seal at the bottom of the fuse.
As the arc rod is propelled upward by the force of the spring, it exits through a seal at the top of the cartridge where it strikes the trigger at the top of the assembly. The trigger releases the ejector assembly which causes the fuse element to swing out 180 degrees to its dropout position. The circuit is now interrupted.
Westinghouse first started manufacturing fuses of this type back in the 1930's. Fuses of this type have been in continuous use in power distribution systems since they were first introduced.
Originally Posted by Worf
That's not a breaker. It's a fuse with explosive disconnect. Basically when the fuse blows, it sets off a bit of black powder that will shoot it off the connector. This ensures positive disconnection even in severe overload conditions (the fuse is sand filled, and it's not unusual for the sand to turn into glass - a heavy overload occurs, the fuse blows but the arc maintains the connection. The pyro charge is set off which aims to blow the fuse off the holder. Of course it doesn't fall to the ground but pivots away from the top contact.
It's why it sounds like a gun going off when it blows - because that's what's happening.
Breakers are dull looking grey boxes, often with a control panel closer to the ground. The control panel allows the lineman to open or close the breaker on the pole, but there is also a manual override on the breaker itself. You want these because they are known as re closers. Basically if the breaker trips, it will start a timer and after about a minute, it will reset itself. If it trips immediately then the breaker will stay off. If the fault clears (fried squirrel drops to the ground) then it will stay on. Re closers are why the power can go out, then briefly come on again before dying. It turns out a lot of faults simply clear themselves because the fried animal or branches or whatever stops shorting the lines and power can be turned on. Customers like it because it causes short outages rather than hours long ones, and utilities like it because it saves rolling a truck to investigate.