What Are Double-Pole Circuit Breakers? - The Spruce Each pole, or connection point, on the bars, carries 120 volts of electricity. When single-pole breakers are installed, they snap into one pole to receive 120 volts. Double-pole breakers snap onto two poles for a total of 240 volts. Circuit wiring that connects to double-pole breakers contains two "hot" wires.240-Volt Power · Tandem Circuit Breakers Double Fusing or Fusing Both Sides of the Line | In Every once in a while, someone asks the question whether fusing both sides of the power line is safe and permissible. Faults. The first question that must be addressed is: What fault protection is the fuse providing? There are two kinds of faults: (1) phase-to-neutral (pole-to-pole) and (2) phase-to-ground.