Circuit that allow the passage of the current and not its interruption
I think you want:


A person to be able to switch on a circuit.
The circuit to stay on until power is removed.








simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. (a) A relay latch. (b) A relay latch with OFF button.

How it works:


Person presses SW1.
RLY1 coil is energised.
Contact RLY1 closes. The relay will now stay on when the person releases SW1.
The relay will now stay on until the power is removed.
Add a normally closed switch for OFF button if you wish.


Connect your load (light, motor, etc.) to contact RLY1b.



Figure 2. Animation of latching relay circuit.