Speedometer at the HEI distributor

Moin together, on the weekend I got a tachometer. Now I wanted to clamp the HEI distributor (MSD replica). Occupancy etc is clear. But is that normal that on the Green cable is always juice on it? So ignition on – Full Pover 11,75 V. Electricity would not have to come after the engine runs. Who knows here advice? Greeting Achim