Calgary police say the cable was swiped over the summer from work sites between Calgary and Red Deer.
The thieves then took the cable to isolated areas to separate the metal from the rest of the cable.
Police say the metal was then sold to salvage yards, netting about $94,000.
Amy Dixon and Kim Dixon of Strathmore face fraud, theft, stolen property and other charges.
Sherry Lynn Crowchild and David John-George of the Tsuu T’ina First Nation and Russell Matheson of Calgary face similar charges.
RCMP and the Tsuu T’ina Nation Police were also involved in the investigation.