Replacing Working Open Wire Poles
I can clearly recall, when South Dakota was completing I-90 near the mid-point of the state, taking detours along the existing U. S. 16 route and witnessing construction and earth moving equipment. Also, I witnessed telephone crews moving existing open wire lines. This was a difficult process, as many of the lines were “working” facilities and while their doom was another ten years away, it was necessary for Northwestern Bell to clear them for the new Interstate right-of-way, and relocate them. Fiber and buried cable placement were decades away, and budgets wouldn’t allow their complete dereliction. They would keep working a while longer–up until 1972. However, the year was 1964. Interestingly, South Dakota was one of the first states to complete its full Interstate complement. Both I-90 and I-29, to their full length, were finished in record time.
As with power distribution and transmission facilities, the economics of service dictated the need for maintaining energized network without interruption. While these telephone conductors were not the high voltages and currents of the T&D world, the importance of vital telecom traffic required their movement while “heated up,” but without the worry of injury from high voltages. This was what we might call “
This process yet required safety precautions and physical labor similar to power, as poles and structures were heavy, guys and wire sustained high degrees of pressure and pull, and replacing them in new locations caused considerable labor on the part of construction crews.
There were several viewpoints regarding how to go about this process without interrupting service. The first was the simplest: by the removal of the pole, with sufficient tension between opposing supports, the wires (and any drops, attachments, & etc.) could be allowed to droop and sag for a temporary amount of time. The pole could be removed, relocated and then aerial facilities rehung on the new support or new facilities tied into the existing line (spliced open wire, guys and strand). However, this method calls into question several potential dangers. The first is accidental open wire pair contacts with wind, ground, and brush. If temporary bridle wire is laid upon the ground, then it might be caught by active construction equipment, run over by tractors in fields, or snagged by cars driving over it. Finally, the opposing poles may not be of sufficient strength or height to support this temporary diversion of wire over a long gap. This tightens the spans on the other poles beyond the two opposing supports and may loosen ties, break pins or pull arms from structures. This deformation resulted in damage and reconstruction which was not desired in any case–either wasted labor time or expense.
These least desirable effects, render a new solution. This is by use of the pole derrick or multi-man crew moving the pole physically to a new location or by a crew gently hopping a smaller party line or exchange pole (typically a Class 6 or 7) to the new site. Let’s talk about transferring open wire lines from one location to another using the mechanical means. The most important of these transfers would have been devoted to large exchange or toll leads, with combinations of either. So, we’ll concentrate on this topic exclusively here.
Existing poles can be reused (by pulling them completely out of the ground and replacing them in a new hole elsewhere) or the existing structure can be lopped off near ground level and services transferred to a new open wire pole. Tangent and corner poles (depending upon how significant the corner pull may be), are shifted in the same way we’ll describe. When the construction forces were required to move a terminal or junction pole, procedures differed. Let’s talk about the easiest process first.
Prior to the construction and relocation activity, the Outside Plant Engineer for the company will have been communicated all the necessary plans of the municipality, county or state highway alignments as well as adjoining earth movements. Such as bar ditch changes, cutting through rock or hillsides or where new fill soil would be placed in preparation for drainage ditches, new bridges and approaches as well as sewer, water and other buried utilities’ siting. Typically, a OSP Engineer or a ROW representative for the company will have visited the site, delivered the proper plans to the telephone engineer and then consummated a proper facilities relocation plan. In addition, I’ve seen where trees which otherwise would not have obstructed open wire or cable lines, now became part of the roadway expansion, and were needing removal or trimming. Usually, the Installation & Maintenance manager or managers (if a big project) will visit the future site and make field notes of any potential problems expected in the relocation. I found the county and state highway departments went out of their way to work with utilities’ personnel on the effort.
Where Do The New or Existing Poles Go?
New right-of-way for the roadway will be noted on plans delivered to the OSP Engineer respecting the typical procedure of placing poles one foot from ROW line, within the public highway alignment. Accurate placement of these holes is absolutely vital. Problem is, when the pole is placed inaccurately, strain might cause the pole to deflect, wires to be strained and transpositions improperly placed. All wires need to be loose on the arms so that the tie wires do not snag or break.
All of these operations occur in “stages”. Many companies complied with the 15/20 rule:
- If one operation to move structures resulted in only fifteen feet of pole displacement and 20 wires on the arms or less.
The changing situations of the site might dictate how difficult or easy this operation would be. That is, moving a four wire (two pair bracketed) line might be really tough if doing this in granite or swamp. Locality dictates the process ease.
With top heavy configurations of open wire arms and a single pole in the ground, once a pole is removed from the ground, it tends to swing in an arc from tension and weight of the arms, pins, wires and insulators. A crew can locate a pole hole (if not previously driven in the ground) when temporarily moving a small lead by using a tape line. Typically, the pole reflects a lateral movement when replacing it in a new hole. As the crew progresses, the hole will be slightly ahead in the direction of the line.
Complicated Moves Where Significant Numbers of Poles Are To Be Re-Set Over Distance
If the lead is a multi-arm, 20 plus wire configuration and the amount of land under transfer is requiring more space between the existing line and new route, then a multi-stage process using mechanical winches and derricks is necessary. Let’s look at how open wire (and cable) leads accomplished this.