Question about power distribution line classification

[moss]

Just did a takedown in proximity to power lines going to an individual house set back in the woods. In this case the poles carried two separated insulated lines which connected to a single-phase step down transformer. The drop line to the house came out of the transformer. I obviously treated the higher voltage "supply side" lines with great respect and followed MAD guidelines.

My question is how would you describe the supply side configuration? The two lines were stacked approx 6-8' apart vertically, with the top line at the top of the pole. I'm guessing the top line is hot and the one below a neutral. Would you call this single-phase or three phase AC?

I took down a tall/leaning narrow diameter tree with mechanical damage and fungal intrusion at the base. To climb it and work safely I routed my climbing line through a big leaning red oak on the opposite side of the powerlines. A good part of the red oak's crown was above the powerlines. The cool part of this is that with one slingshot throw I was able to put the throwbag through three crotches on the oak and base anchor back in the woods giving me a super "no-climbing" line set. I was then able to do the takedown with nothing anywhere near the power. Nevertheless I like to know exactly what I'm looking at when it comes to powerlines. Always treated with great respect, even more so when the lines are before the transformer.
-AJ

 

[Reach]

If there are only two lines on the pole, spaced vertically 6 to 8 feet apart, that should be single phase. To have three phase, you must have three conductors, occasionally these three conductors will be stacked close together, but typically they are spaced out horizontally on a cross bar at the top of the pole.

You are correct in your guess, the line on the top of the poles is the hot wire, the line below should be the neutral.

 

[Tony]

Yup what Reach said. Single phase. Most likely 7.6 kV nominal voltage. By ANSI standards an approach distance of 2’3” for qualified, 10’ non qualified. MAD includes both lines and transformer.

Tony

 

[oldoakman]

Good on you for being cautious and seeking sound advice. Maybe should have sought the advice before doing the work though.

 

[moss]

Good on you for being cautious and seeking sound advice. Maybe should have sought the advice before doing the work though.

No worries, My body and line were outside of the "non-qualified" 10' MAD for the entire job. No pole saws being used. I've worked and climbed around lines for more than 15 years and have read every tree worker/powerline accident report I've ever come across over the years. I haven't taken an EHAP course which I should do. My most basic powerline rule is I never work in trees in general proximity to wires when it is raining or the tree/bark is wet or damp. For this job my main safety consideration, everything else being good (dry, respecting the non-qualified MAD) was being very sure uncontrolled swingback would not occur and cause me to violate the MAD and being aware that for every cut of a every branch that I had complete control of where that branch or wood was going during/after the cut. With the tree leaning away from the lines it was not difficult to maintain that standard but... it's all about staying on point 100% of the time during the takedown. Which of course we all strive to do whether there are powerlines or not.

My question was not advice about working around powerlines but identifying this particular configuration. In my residential tree work I'm seeing house drops 99.99% of the time. I see a lot of three-phase but never had to or chose to work anywhere near it. Since these were obviously higher voltage lines on the supply-side of a step-down transformer I was really curious to specifically identify the configuration. I'm always cautious around house drops and follow the MAD guidelines. For this situation was hyper cautious. During line setting I was particularly careful that throwlines and ropes never got near the MAD. For example I had to move the climbing leg of the redirected rope through a bunch of small branch ends to get the rope where I wanted it. That was the most vulnerable moment in that it was possible for the rope to cause a small branch end to get too close to the hot line. I was paying attention.

I was back on the site yesterday doing another takedown quite far from the lines (couple hundred feet). I was ground raking at the first takedown site and took another look, the hot and neutral were stacked only 3' apart not 6-8'. It all made more sense, the hot line was attached on the top of the pole with an insulator, the neutral line was attached with what looked like a grounding clip/bracket, with the insulation striped off for the wire at the bracket.

Thanks for your concern, much appreciated.
-AJ