galvanic isolation of pole guying 1

[bacon4life]

In thread238-162891 advidana mentioned that "an insulator is required on the guy line from the pole to the ground for galvanic protection"

What sort of a configuration requires that?

We require insulator in guys, but I was told is was so that if the top part becomes accidently energized, the public cannot walk up and touch a hot ground wire. Also it allows workers on the pole a measure of safety if they touch something hot and the top of the guy wire. Some utilities do the opposite, requiring everything thing to be grounded so the relaying will operate faster, especially in areas where the soil is poor.

 

[jghrist]

The usual reason for a guy insulator is as you noted, for safety if the top of the guy is in the primary area. A fiberglass rod guy insulator is also often used to increase pole top BIL. If the guy is bonded to the neutral and the neutral is grounded separately with a copper ground rod, then galvanic corrosion will be likely. The galvanized anchor rod and anchor will be a sacrificial anode to the copper ground rod. A guy insulator will prevent galvanic currents from flowing.

 

[advidana]

Thank jghist for good explaination on the use of the guy insulator.

 

[MikeDB]

Use of a guy insulator will reduce, but not prevent, galvanic currents. If there are disimilar metals like galvanized anchor and copper ground wire, the galvanic action can take place in low resistivity soils, even if the two metals are not bonded together. The use of galvanized ground wire and rods with galvanized anchor rods is one solution.