plenty of talk

[reppy007]

ok heres 1 question ...your pulling in several spans of wire...Ive seen guys refer to a chart,making things harder than they have to be ....we have always had a guy get a ways back to EYE the sag ....does anybody really use any kind of chart?

[linemanfrog]

ok heres 1 question ...your pulling in several spans of wire...Ive seen guys refer to a chart,making things harder than they have to be ....we have always had a guy get a ways back to EYE the sag ....does anybody really use any kind of chart?

If pulling in smaller wire just a few spans, no I do not use the chart. However if pulling in more than a few spans or so of 397 or larger I always use the chart, a thermometer, and a dynometer. I've seen the ill effects of eyeballing too many times. Usually you will find that wire pulled in using the eyeball method may look good at the time of sag but in a few months looks like crap. Initial sag of larger conductors is a must in my book, let it set for at least a few hours, check the deadend and angle pole guys, straighten poles if need be, then pull conductor up to final sag. If eyeball sagged during the hot parts of summer then conductor usually will be too tight in a cold winter, and vice versa. I was also taught no to go off of ambient air temprature because that does not give you an accurate temp of the conductor. Think of how hot the shiny diamond plate tool boxes get during the summer with the sun beating down on them, the same can happen to wire on an open right of way.

I've used the Unisag watch a few times, but much prefer the use of a dyno on each phase, it takes all the guess work and going back and forth a thousand times out of the equation.

[Lineman North Florida]

Like lineman frog said, 3 dynamometers and 3 hoists, done it all kinds of ways but like the 3 dyno method the best.

[wudwlkr]

You apparently have never been involved in an electrical contact accident lawsuit.

NESC has very specific requirements as to clearances above ground or other objects. Conductors must maintain those clearances under several different temperature, wind and ice loading conditions. While a line that was eyeballed in may look good at the time it was installed, it may not meet clearance requirements under other conditions. Sag charts are designed to keep clearances proper under all required conditions. They will give you sag in inches or tension in pounds that the conductor should be pulled up to. Tables can be used to get proper sag by timing bounces, pulling tension or sighting in with level boards or transit. Only tricky part is they are based on ruling span not actual span lengths.

All a plaintiff's lawyer has to do is show that under one of the NESC specified conditions your conductor falls below minimum sag. Doesn't even have to the the conditions in place at the time of an accident. If your conductor doesn't meet all conditions it is in violation of NESC and you lose. And you are going to sit in front of a jury, who hate utilities anyways, and explain to them about your "calibrated" eyeball? Lots of luck.

[T-Man]

You could follow all sag criteria. . . Then the cable company's come along and pull their messenger so tight with a truck, they bag all the wire, electric and phone. They had our system so messed up in the 80's. .

[bren guzzi]

Always use a sag chart on new builds.

But only one dyno on the middle phase. Reg the others too it. ( obviously on flat construction )
On towers we used sag charts and sag boards.

Why leave it to chance ? Our temperatures flucktuate quite a bit over the course of the year.. So no sag charts could mean clearance issues in the summer.

[rob8210]

I have sagged by eye, using sag boards, and using dynamometers. I prefer the dyno's for accuracy , when they are calibrated correctly. Not many crews carry them here.

[reppy007]

Id love to see how a dyno works..I have no Idea at all.

[Pootnaigle]

Works jus like a scale does it tells ya how many pounds o fstrain ya have anna half a notch on yer hoist will send it wayy up there

[reppy007]

sounds good to me Poot...I guess we are behind the times over here .Maybe time and money plays a part.