I need to provide overhead power line clearance for a project. I have no problem with determining the remote height above the ground. My question is, how to determine where the observation should be made? Should the observation be made at the lowest point of the line or over the centerline of the road? The lowest point seems intuitive until you observe the lowest point on a line that is directly adjacent to a power pole. Thanks in advance for the help.
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We usually tie the nearest pole structures either side of the road, attachment point of line to pole, lowest point of line and edges of road.
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What Kristopher said. The lowest point of the sag is rarely on the center of the clear roadway. It can be difficult to "see" the lowest point with your eyes. Several shots along the conductor or strand will generally reveal the "flat spot".
FYI - throw in the current temperature at the time of your observations.
And if you're ever asked to provide a profile of the low conductor (attempting to pass some sort of mathematical ju-ju through points you've shot) remember the sagging cable is a catenary and not a parabola.
https://en.wikipedia.org/wiki/Catenary
You show the height of the existing structure at the point you are crossing/intersection with the existing structure and give the height of your proposed structure at that point.
That has to be in compliance with the standards/codes of your local area.
Your local electric company should have a copy of those specs along with the DOT of your state according to the ratings applied to different roads and ratings of what can pass thru what corridors.
paden cash, post: 397072, member: 20 wrote: What Kristopher said. The lowest point of the sag is rarely on the center of the clear roadway. It can be difficult to "see" the lowest point with your eyes. Several shots along the conductor or strand will generally reveal the "flat spot".
FYI - throw in the current temperature at the time of your observations.
And the time of day so the power company can determine the "load" that was being transported at that time. It creates additional sag (coefficient of expansion-remember that from the steel tape days?), especially if it is a main powerline.
BushAxe, post: 397053, member: 11897 wrote: I need to provide overhead power line clearance for a project. I have no problem with determining the remote height above the ground. My question is, how to determine where the observation should be made? Should the observation be made at the lowest point of the line or over the centerline of the road? The lowest point seems intuitive until you observe the lowest point on a line that is directly adjacent to a power pole. Thanks in advance for the help.
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Here is an example of the U.S.B.R. procedure that they used for their route surveys when crossing a transmission line. The procedure would be the same whether it was a road survey, transmission line survey or gas/oil pipe line survey. I hope that these are readable, as I've had them for almost 60 years and they're kinda like me, old and weathered.
The file is too large and it appears like I will have to scan each page individually and post them one at a time
Charles L. Dowdell, post: 397110, member: 82 wrote: Here is an example of the U.S.B.R. procedure that they used for their route surveys when crossing a transmission line. The procedure would be the same whether it was a road survey, transmission line survey or gas/oil pipe line survey. I hope that these are readable, as I've had them for almost 60 years and they're kinda like me, old and weathered.
The file is too large and it appears like I will have to scan each page individually and post them one at a time
Dropbox link???
BushAxe, post: 397053, member: 11897 wrote: I need to provide overhead power line clearance for a project. I have no problem with determining the remote height above the ground. My question is, how to determine where the observation should be made? Should the observation be made at the lowest point of the line or over the centerline of the road? The lowest point seems intuitive until you observe the lowest point on a line that is directly adjacent to a power pole. Thanks in advance for the help.
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Here is an example of the U.S.B.R. procedure that they used for their route surveys when crossing a transmission line. The procedure would be the same whether it was a road survey, transmission line survey or gas/oil pipe line survey. I hope that these are readable, as I've had them for almost 60 years and they're kinda like me, old and weathered. This is the first time I've looked at these in a long time and they are really turning color. I guess that I'd better scan all these documents that I have from the time I was employed by the Bureau of Reclamation.in order to save them before it's too late. There are a lot more pages of survey notes for transmission line surveys, as well as a lot of other good stuff I got when I was employed there.
I can only upload a page at a time it seems like. All 3 pages together were too large and gave me an error, so I rescanned them individually.