I recently completed a survey that will likely go to court involving a surveyor who was electrocuted when his prism pole hit high voltage lines. Of course I dont know the whole story and wouldn't post it if I did, but I do know he was injured but survived. I worked with him for a few months about 15 years ago. About 12 years ago another surveyor was killed in a similar accident.I had just met him a week before. Both were on St. Thomas.
Working on that survey made us both feel a little queasy.
Be careful out there.
aluminum pole he was using touched a live hydro
He wasn't a surveyor but, we too use aluminum rods .........
He and his wife and two children had just moved into a new house we had surveyed.
Derek
Larry, it keeps on happening, everywhere, far too regularly. You can't see it, smell it or hear it (mostly) and it's instant.
I posted this about 5 weeks back:
"Having seen a large excavator strike three 33kV overhead lines last week I'm getting rid of the aluminium levelling staff. Biggest surprise after the flash and bang was that the driver and machine were unharmed, I fully expected a fireball."
I was back on that site recently and measured from the roadway to the overhead line using a laser Disto - only 5.4m so there will be some awkward questions to answer.
In the early 1970's a rodman was electrocuted while doing an inverted rod reading to a rural distribution line. He was using a wooden Philadelphia rod and they never considered that it contained a metal ruler. The rod never touched the wire, the highly powered source of electricity arced to the ground thru the rod and man before that happened.
A few years afterwards I went to work for the same company and. The crew was using a ball of chord and weight to throw over the lines and then measure the marked length of chord with a chain.
I immediately taught them how to shoot the rod, note a distance by stadia from the instrument to the rod and turn an angle up to the wire.
I will always remember a squirrel go "poof" trying to cross a large transformer, not a pretty sight.
Glad the new equipment comes with laser and other perks.
0.02
Read with caution, this may be a little too explicit!
Working for a major electric utility company and being a PLS, I surveyed and stamped a few "accident sites" over the years. Sometimes it's not a pretty site. i.e. points of contact with remaining human hair, flesh etc. It's always a major issue of the height of the conductor above ground and if it's within the National Electrical Code for the voltage of the line. Today with laser measuring tools, makes it so much safer (I wish we had one of them back in the day) The gist of my little story is for surveyors to respect or be aware of overhead powerlines in your work area. They may look innocent but they can be dangerous and are silent killers if contact is made. Residue, dust or liquids on a wooden rod can carry enough conductivity to make a person part ways with this world. To give you an idea of the power, I surveyed a "site" where a young promising high school football player was moving aluminum irrigation pipes with his brother. They were seeing how far they could balance the pipe on end and who could take it the farthest. The pipe and kid made contact with a 33.5 KV powerline and it blew (literally vaporized) both legs off the kid and he was killed instantly. Just be aware of any overhead powerlines in your work area.
Pablo
Read with caution, this may be a little too explicit!
My first chief of parties, James Warner was chaining through some tall wet grass under a high tension power line. Jim was holding rear chain and the head chainman had gotten off line. He got back on line and the flipped the chain up over the tall grass. When they did that, a big arc of electricity came down out of the wire and hit the chain. Jim said he did a dance called I can't let go and the next thing he remembers is waking up in the hospital. He had burnt the bottoms of his feet. His socks had melted into the soles of his feet.
> (always) Just be aware of any overhead powerlines in your work area.
>
See Caltrans website for training material, state specific for legal statutes.
http://www.dot.ca.gov/hq/row/landsurveys/Study_material/index.html
When I first got out of school oh so many years ago, I worked on a large commercial site adjacent to a BPA transmission line. Just being under these thing the radiant electricity caused a roller to vibrate. Our Wild 2002 was fried by the damn things one rainy day.
Best to treat these things with respect and keep your distance.
For high voltage transmission lines remember that the height or clearance can change over time. If a line is placed in an outage it might have one clearance and other clearance while operating at maximum design conditions. These differences can be more than you thing depending on the span length, conductor type, wind conditions, thermal loading, and operational loading just to name a few. As was said give these lines their due respect.
If you're working on a project where you have to show the clearance you might consider talking with the power company about obtaining their design drawing to show the proper clearances instead of just the clearance at a particular time on one day.
Same could happen when digging for or setting monuments. Safety First
dpsluss, I measured the clearance for my own interest, the clear height was well below the required 6 metres and was measured quite close to one of the poles, definitely not near midspan. The track has been getting built up over the years of pot hole filling and attempts to get a camber on it. Going on the side slopes it's probably risen 0.6m!
