Curious Cutout Fuse 2

[DRWeig]

Just a curiosity question --

Yesterday morning we heard the big "boom" and had the usual ensuing blackout in my residential area east of Atlanta. This one sounded like it was on our street, so I set out for a nice walk with my daughter so that I could teach her what all the things on the pole-top are about.

We found it about three houses away, but the fuse was not hanging. It was still snug in the cutout but turned a lovely shade of mahogany brown from its original bright white.

The trouble happened on top of the pole-mount transformer (easy to tell), downstream of the cutout. The whole circuit went down, though.

I just wondered if the fuse that turned brown was probably blown but didn't drop, or if it actually survived but just cooked itself a bit. I didn't get to ask the lineman, he came and went like a flash. Does this happen often? Can a cutout fuse open up and stay in place? I don't have much distribution-level experience, but all the boomers I ever heard had a dangling fuse when I saw them afterward. I thought one of y'all might educate me, as if you don't do that every day already...

By the way, the charred squirrel meat was tasty but a bit gamey. I recommend Heinz 57 sauce to liven it up.

Best to you,

Goober Dave

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[waross]

I had that happen once. As soon as I touched the fuse with a hot stick it dropped open. Your cutout may have had a bad spring. There is a paddle on the bottom of the fuse holder under spring tension. When the fuse blows, the spring loaded paddle snaps the bottom part of the fuse link down and increases the clearing distance. This also allows the knuckle to collapse to remove pressure on the top of the fuse so that it may swing down. If the paddle didn't pull the fuse link down for any reason, there may possibly be an arc inside the fuse holder. That could give the color you described.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[DRWeig]

Thanks Bill, that makes good sense to me. I'll sleep easier.

Best to you,

Goober Dave

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[hdp]

I believe Bill's post is on the money. I worked for years for a mid-southern utility. One particularly bad storm involved a heavy freezing rain. It was a 20 year event. We started patrolling, looking for open cutouts. We had to backtrack when a veteran explained that the fuse barrels might be frozen in place. You had to examine the bottom paddle as Bill described, looking for a slack link.