Wednesday, October 24, 2012

What are these?

Out on a bike ride this morning, I saw these things that look like trapeze bars hanging from power lines:

Right-click on photos to see them full size.

The ones in the first picture are over a wash. The ones in the second picture are over the adjacent bike/pedestrian trail. The lower one in the second picture is obviously broken.

I can't figure out what they are. They look like they're made for somebody to hang from, but that can't be right, because hanging from a thin power line, they couldn't support much weight.

So my second thought was that they are height markers of some kind, like the bar you pass under before entering a parking garage, to warn too-tall vehicles not to proceed. But that doesn't make sense. They're hanging over a wash, where there shouldn't be any vehicles to warn. Besides, they're way high--you'd need a cherry-picker kind of thing to reach them. There's nothing else anywhere around of comparable height for which they could serve as a height marker.

I'm stumped. But I'll bet that somebody among my highly intelligent readers will know the answer, or at least be able to guess at it better than I have.


TenMile said...

Figure out the winds.

TenMile said...

Try figuring out the winds.

Jason said...

My best guess is a wind damper. I believe that the 'stick' serves to act as a sort of counterbalance and minimize the effects of wind on the line.

Anonymous said...

Probably something to reduce wind-induced oscillation.

Anonymous said...

I believe that there are visual markers for construction that is taking place near the power lines. Note the third paragraph below, from:

Barrier Protection

Another option that your company may use is barrier protection. A barrier prevents physical contact between the high-reaching equipment and the power line. It can be made of any material that is non-conductive and not attached to the high-reaching equipment. The most common type of barrier is the insulating sleeve which is attached directly to the power line. Workers have been electrocuted when insulating sleeves have failed and the equipment they were working with became electrified.

If insulating sleeves are used, they can only be installed by power company personnel. Also, the sleeves must be appropriate for the type of work being performed. Most important: even with a insulating sleeves, you may not work any closer than the required clearance distance.

On many projects, power lines cross over temporary and permanent roads. Even though work may not be done around these lines, contacts can occur as equipment passes under them. To address this problem, your employer can use physical barriers called "goal posts" or "rider posts." This type of barrier requires equipment operators to lower their equipment below a physical barrier placed under the power line. This barrier is an active reminder of the presence of overhead electrical line.

buttnugget said...

I've seen these before somewhere. As I recall I was told they were markers of the power line for construction workers who will be use high equipment (crane) to give them a point of reference especially at night. Having them marked meant they didn't have to hire a safety crew to watch their every move which costs a lot. The power company installs them. They're temporary.

unaha-closp said...

They are probably height markers for when the wash is cleared out using a heavy excavator.

Rakewell said...


That seems to me like the most plausible answer yet. Lacking any actual information, I'd judge you to have about a 90% chance of being right on the money. Anon's info about construction work was useful and pointed what I now think must be the right general direction, but there's no construction going on where these things are. Heavy equipment occasionally brought in for cleaning seems perfectly plausible, and they would certainly want to make sure such things stayed well below the power lines.

Anonymous said...

77Pretty sure they are elevation or height markers. used in construction areas where it is a concern. they are hanging from power lines and the crossbar is at the standard minimum height for telephone/tv cables (or a known low cable elevation)