pole ground question

[kooman]

hello guys, i am a new member but have been a lineman for 17 years now. on our system we use mostly wye voltage sheilded construction and when we build v or 3 phase it has allways been standard framing to run the pole ground down to an insulator on the arm and then back to the pole. well the other day our manager said he didnt think we needed to do this any more and wanted to just run it straight down the pole with moulding on the opposite side of the center phase, to me there must be a reason why most systems run it out on an insulator. is it just for clearence reasons or exactly what is the reason for doing this? thanks guys and be safe

[topgroove]

i'ld say standing the down ground off on a insulator would be a complete waste of time.

[Lineman North Florida]

Everywhere that I've worked we pulled the pole ground top to bottom stapled it into the pole,never stood off on insulator and have never heard of it before today.

[kooman]

Everywhere that I've worked we pulled the pole ground top to bottom stapled it into the pole,never stood off on insulator and have never heard of it before today.

yea i wasnt sure on how the rest of the country framed it but around here (midwest) you see alot of line with the ground on an insulator on the arm.

[lewy]

We also never insulate our neutrals from the pole, we install hubbard clamps on all of our tangent poles & would be connecting our down ground to it. We are just a wye system, we only run a system neutral 10'6" below our primary with no sky wire.

[Lineman North Florida]

yea i wasnt sure on how the rest of the country framed it but around here (midwest) you see alot of line with the ground on an insulator on the arm.Kooman do you work for a Co-op?

[kooman]

Kooman do you work for a Co-op?

i work for a locally owned utility, we have only 4000 customers in 5 smaller town and approx 300 miles of rural line.

[Lineman North Florida]

10-4, I've never seen it in the SE US, but there are people on here from all over that may have,it could just be one of those things that at a small place has always been done and no one really knows why, they just know that old so and so told them to do it that way.:D

[LostArt]

.....oh pahleeze....not "old so and so" again!!!:D:p

Welcome kooman.

[Trbl639]

when I worked for a co-op, in the late 70's, if I remember right, it was a co-op spec on shielded to have it on an insulator on the arm away from the pole........the local co-op around here still does it that way, and it's not the one that I worked for......

[topgroove]

I believe he's talking about the down ground Swamp

[lewy]

In todays construction why would we still be putting the neutral on the arm for normal construction? I know there might be certain situations where you might have too, but I would think most times it should go below the arm.

[kooman]

thanks for all thi input guys, i was just curious as to the reasons behind it.

[kooman]

In todays construction why would we still be putting the neutral on the arm for normal construction? I know there might be certain situations where you might have too, but I would think most times it should go below the arm.

we dont build much r.e.a. spec, we allways build sheilded, neutral on pole top then arm 5' down, trying to tame the lightning a little. :)

[lewy]

I might be wrong, but I do not think the position of the shield wire for distribution has that much effect on lightning. I was driving through Miami last year & I don't think they ran a shield wire above there primary, but I think they had arrestors at every second pole. We do not have the lightning that they have so we mainly just place them (arrestors) at transformer poles & dip poles.

[wtdoor67]

build some 14.4/24.9 on a shielded/neutral type construction where the neutral/shield was on the top on a ridge pin. It had an arm about 3 or 4 feet down from the top with the 3 phases on it.

Their method was a ground coming down the quarter of the pole to about 18 inches above the arm, it then left the pole and was stretched to an insulator that was mounted on the arm horizonally, tied in and then back to the pole after about 18 inches and then on to the butt. I never inquired as to the reason for this as we built 12470 under the same type of construction but ran the ground straight down to the butt.

I have also seen 69 KV on single pole construction with the 2 or 3 fiber glass stick pins with the ground on them. Have also seen wood 230 on H fixtures with the same type of stick pin holding the ground wire up in the area of the arms and then back to the pole etc.

Now it's been mentioned I'd like to know the initial reason for this type of const. There must have been an initial reason or purpose for this but I don't think it must have been well researched as I've seen the same type of const. in the same voltages and areas, some with the insulators and some without.

[wtdoor67]

impression, and I never verified it, was that it was to increase the BIL of the thru bolt and arm area.

[spark and bark]

Well, when i worked in southern idaho, they bonded everything to the system nuetral. Even ran a jumper from the arm split bolt to insulator pin. I guess the thing that totally baffles me is why would you bond guys, bolts, braces, standoffs, etc. and then put the system neutral on an insulator, or dead end it on one? What is the point if the entire pole is bonded? I understand on 230 or 115kv,but on on 7.2 or 14.4kv? Guess its just more sh%t to pack on a truck and another thing to break when wreckout comes around....

anyways, up here on hi-line, i still have never seen a shield or "lightning line" on an insulator. Seems to me that you wouldn't want a highly resistive insulator seperating pole from ground wire. Hot spot, diff. in potential, who knows. Just doesn't seem practical.

[wtdoor67]

seen plenty of insulated shield wire on 345 and 138 KV. Used for telemetry and carrier phones I think. Even crossed the shield wire on some structures for a tranposition just like a typical telephone line.

If you're doing something hot on a transmission line you don't touch the insulated shield wire without grounding it. It will light you up.

I think the use of carrier phones is probably falling out of favor. However I've used them plenty in the sub to talk to dispatchers etc.

The ground insulated as spoken of in the first post on this subject also has something to do with radio noise prevention.

This is a good subject as I hadn't thought about this particular thing for a long time. Bet there's someone with gobs of experience on here who will bring us up to date on it.

As I remember the ground wire on the structures just went up and bonded to the static bar. The shield wire was rodded over a little neopreme thing and hung on a little dangle down insulator similar to a distb. DE bell.

I'll bet Battman can fill us in on this subject.

[climbsomemore]

I've seen it pulled out to an insulator like that... but the neutral was mounted on a ridge pin at the pole top... like a sheid wire system.

I never got a good answer why that was when we worked on those

Co-ops typically dont do it... neither do a lot of other places Ive traveled through or worked for either... staple the wire down ...even the moldings optional company to company