Upgraded larger insulator
This is done for the purpose if raising the voltage on the wires attached to the insulators. The lines at the top of the pole are medium tension, usually around 7000-8000 volts to ground but could be as low as 2400 and as high as 30,000. Larger insulators are needed so higher voltages don't jump across to metal or rain-soaked wood framework underneath.
Raising the voltage allows the same wire to carry much more energy (in watts). It will stilil carry the same number of amperes as before for a given allowable voltage drop (representing energy waste) in actual volts. It will carry more amperes as well as the increased voltage for a given allowable voltage drop in percentage of volts, limited by how hot the wire is allowed to get as a result of current passing through it. The energy lost in any section of wire is watts equal to the number of amperes flowing times itself times the resistance of that section aka the number of amperes flowing times the number of volts dropped in that section (the number of volts we start out with does not matter).
Most likely the changeover will cause a brief outage for each customer as each pole transformer is exchanged (if not already) for one that takes both the old voltage and the new voltage, and another brief outage when all the transformers are disconnected, the voltage increased, and all the transformers reconnected using different "taps" so the output voltage (120/240) stays the same. There may or may not be another brief outage when the dual voltage transformer is swapped again for a single higher voltage transformer and the dual voltage transformer is available to be used someplace else for a voltage upgrade.
The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.
Last edited by AllanJ; 04-13-2011 at 05:09 PM.