Where does the 110V AC voltage for the circuit come from?

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There was a strange issue with the wiring of a newly installed SIS relay cabinet. One cable was used to control 110V valve solenoids, with 10-core cables in total, two per solenoid. It was found that one of the solenoids received power at the site and caused the valve to move. Upon checking the circuit, it was discovered that the corresponding fuse switch in the SIS relay cabinet had not been turned on. Using a multimeter, it was confirmed that there was indeed 110V voltage at both terminals. When one of the wires was removed, the valve stopped moving and returned to its closed state, indicating that there was no problem with the circuit wiring. However, even with the switch still off and one wire removed, there was still 100V voltage at the output terminals. When the other wire was reconnected, the valve moved again I really can’t figure out what the reason is. Since no power is being supplied, this terminal still has electricity. If I remove both wires connected to the output terminals, does that mean the output terminals lose their power? As long as one of the wires is connected, do these two output terminals then have a voltage of 110V? Really don’t know what to do? It was finally decided to run another cable, but to our surprise the problem persisted – were all the connections fine? What should I do?