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Luke
08-13-2006, 11:33 AM
This is my first time on the linemans fourm. As most of you know Bob Tackett
lost his life working for Ameren in the recent storm in St. Louis. He will be greatly missed. Since that time there has been a lot of talk about personal voltage detectors. We have and are still testing one called the V-Watch. We've had some mixed reviews on this device. One of the problems with it is if a hot primary is laying on or near the ground it will not warn you. What about laying in trees or brush ?
Could someone provide me with some info. on any other detectors that you or your company may be using that will work on these downed wire situations.

BigClive
08-13-2006, 03:02 PM
They tend to work by detecting the voltage gradient in the surrounding area, so just like the little "Volt stick" testers used to trace lower voltage cables they can presumably be fooled by cables in close vicinity to a ground plane (earth!) or worse still, wet foliage screening the field from the cable.

I suppose it's a compromise. If they're too sensitive they'll false trigger on static charges and if they're too tame they won't detect cables in the foliage.

Given that a downed cable will generally track about a bit and generate a bit of heat in the local vicinity, I wonder if a set of thermal imaging binoculars would be useful for detecting a situation like this. They'd also be useful for their existing purpose of finding bad connections and taps.

That's assuming the management would actually buy them!

SouthernYankee
08-13-2006, 10:52 PM
We recently tested the V-Watch here a short while back with not promising results. To be truly effective, a person would have to have 2-3 of them on their body. One being worn in a position hanging from the neck, one on the belt, and other worn attached to boot. In our tests, if it was worn at one of the recommended places ( the neck ) it would pick up a single phase or three phase line from 60 feet away if you happened to be pointed directly at it. Turn body a little bit and you then had to get about 30 foot away or closer. If worn in other main recommended spot of on the belt, we was able to walk directly under lines with no alarm. These tests was done on a low set of remote lines that was on 30 foot poles. Also we read in their manual and found in our tests , is that brush, fencing, and the closer the line is to the ground severely reduces the alarm distance to almost nil. I am all for what ever it takes to make this job safer, but sadly these devices need more work. If a person was relying on this for some unknown reason, and not mainly using their eyes and head, they would grow too accustomed to the alarm ringing for lines in the air and still walk right into one in heavy brush or on the ground.

igloo64
08-27-2006, 01:06 AM
Thats The Best Method. If Its Not Grounded Its Not Dead . Any Other Way You Would Be Dead And Not Grounded. No Such Thing As An Accident. They Can Be Prevented.

duckhunter
08-28-2006, 02:01 PM
I agree with Igloo. We use the Salisbury tester and I feel better walking with it set on 240 than the V-watch.