Guessing power line voltage from the number of disc insulator

Is there a good way to guess the power line voltage based on the number of insulator discs that attach the line to the transmission tower?

Wikipedia seems to suggest that there is a "Typical number of disc insulator units for standard line voltages".

Is this a good ball park upper bound to the voltage on the power line?
Is there a better way of guessing line voltages?
Is it possible to further refine this guess based on the type of insulator discs?

Answer

Is there a good way to guess the power line voltage based on the number of insulator discs that attach the line to the transmission tower?

We usually use as a rule of thumb for determining the number of porcelain/glass suspension disc insulators: 10kV for each disc (standard 5-1/4' x 10").

For typical system voltages in North America, this would be:
69kV: 4-6 discs; 115kV: 7-9 discs; 138kV: 8-10 discs; 230kV: 12 discs; 345kV: 18 discs; 500kV: 24 discs.

You may check Electric Power Generation, Transmission & Distribution by Grigsby, et al.