Article
Across the street from my front porch sits a utility pole. The fuse for 
the transformer that feeds our part of the neighbor hood sits high atop 
it.<br><br>And at least once a month … our power would go out.

OF Fuses, Utility Poles … and Squirrels

Steve Maurer, IME
Across the street from my front porch sits a utility pole. The fuse for the transformer that feeds our part of the neighbor hood sits high atop it.

And at least once a month … our power would go out.

One morning, I woke up to a dark house, and a racket going on in the street. It was the utility company, working on the pole.

I meandered out to see what was going on. They had opened the cutout/arrester combo, killing the power. The leadman told me the fuse hadn't blown, though. They were installing a squirrel-proof cage to keep the little darlings from shorting the power out.

I chuckled, watched for a while, and then went back into the house.

Before long, the power came back on and I was able to make my coffee. I watched as they left, keeping my fingers crossed.

Sure enough, the power went off about 30 minutes later.

I wandered back out to the pole, coffee and cellphone in hand. I dialed up the power company to let them know … watching the smoldering little pile of fur at my feet.

The squirrels are pretty smart in my neck of the woods … but then again, maybe not that smart.
When they came out this time, they brought a slick metal shield to wrap around the pole so the critters couldn't dig into the wood.

I imagine it's just a matter of time before the furry miscreants discover suction cups.

Choose the correct gear
As you're probably aware, not all fuses and switches are created equal. You need to pick the correct one for the job.

For example, loadbreak cutouts and linkbreak cutouts both are used to interrupt load currents. However, the way they operate is different.

With a linkbreak cutout, the lever is pulled down forcefully, pulling apart the fuse link in the fuse holder. Each time this is done, the fuse link must be replaced.

Switches
Some switches are specifically designed to control shunt capacitors for line filtering and power factor correction. The switches are fully enclosed and "wildlife friendly." However, additional visible switches must be installed to ensure the line worker can maintain the switch safely.

Some switches are used to either shut off or reroute power. Some are hook stick operated, while others have rotating insulators to open and close the switch.

Automatic reclosers and interrupters are available both with and without Wi-Fi radio operation and programmability.

Let's hope the squirrels don't learn how to operate them. Right?
On the loadbreak cutout, the fuse holder is pulled away from the top contact and the current path is redirected through an auxiliary blade. When pulled farther away, the arc chutes extinguish the arc that inevitably forms.

Because of its construction, the fuse link does not need replaced each time the loadbreak cutout is opened.

Additionally, the fuse holders are designed for a specific range of fuse amperages. Just because the fuse link fits inside the holder, it doesn't mean it will work properly.

Shortening rods are used to accommodate the different lengths of correctly specified fuses. But ranges will have diameters that much be matched to the fuse holder properly.

Cutout fuse links are often designed with a removable button head.
Photo courtesy of Hubbell Power Systems, Inc.
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