In my experience (also in the USA), the opposite is true. High-voltage transmission and subtransmission lines are indeed protected by a grounded static wire above power conductors. But distribution lines are rarely fitted with static wires.
Of course, the MGN (multi-grounded neutral) forms a continuous ground along the line. But the MGN is usually located below power conductors.
See "Joint Pole" in any recent edition of Newton's Telecom Dictionary. An expended version of the same definition is at
Telcos usually require 12-inch separation between their facilities and any other facilities on the same pole.
Every pole attachment agreement I've ever seen specifies that CATV must be placed at least 12 inches *above* telephone cables. And since telcos were usually there first, they have the right to dictate the terms to the CATV companies.
The 12" clearance requirement provides both companies space for the lasher -- the device that spins the lashing wire around the strand and the signal-conducting cables. See
Not necessarily. Even in urban areas, telcos often set their own poles in places where no power pole exists. As you note, many of them are small short poles ("toothpick poles"). But at least as many are designed for joint use even if the immediate need is for telco only. I've often seen telco-only poles with 10 or 15 feet of unused space sticking up above telco for future power use. (Good thing, too: those poles provide space for CATV 12" above telco, and still leave space for power in the future.)
Wes Leatherock responded to that comment:
Depends on the local situation.
In the case of investor-owned (for-profit) utilities, Wes's statement in generally correct: power and telco strive for 50-50 ownership. And, as Wes notes, there are situations where telco owns a pole used only by the power company, and where power owns a pole used only by the telco.
But there are exceptions even to that. When I was working in cable TV in Madison, Wisconsin, we were never quite sure who owned which pole: some were 100% Madison Gas & Electric; some were 100% Wisconsin Telephone; some were 50-50; still others were odd combinations like
60-40. Fortunately, it didn't make much difference to us: we just submitted all pole applications to both companies and let them sort it out.WisTel's pole records were maintained in a central computer database at their headquarters in Milwaukee. MGE's pole records were hand-written in a 3-ring notebook. Guess which one was more accurate.
In the case of municipal utilities, most joint poles are owned by the utility; i.e., the municipal government. When the city owns the power distribution wiring, the poles that support it, and the underlying land, it can pretty much dictate the terms to everybody else.
Robert continued:
True. However, telco cables can be pretty heavy too; I've seen multipair cables almost two inches diameter. In order to prevent sag, strands supporting big cables like this have to be placed under high tensions, often several hundred pounds. Further complicating the situation, some polelines carry two or more telco cables. An extreme example:
Add three inches of radial ice and a 100-mph wind, and communications cables can put a huge lateral force on a poleline.
Neal McLain