I am using this Normally Closed Relay on a 24V circuit: DataSheet
The circuit is 24VDC source, which I measured the Amperage in series to be 29mA at the highest. I've breadboarded a lower voltage circuit (5V) fine with the relay. When I put the relay into the 24VDC circuit, I am able to open and close the circuit one time, but it burns out the relay: the relay can never be switched open again. I notice when switching it under the 24V load that when I close the switch again, it delays before completing the circuit.
For the switched circuit: I have 24VDC source connected to pin 1 of the Relay, and the rest of the circuit connected to pin 4 which is connected to a the magnetic door lock (and a push to exit button, which may use a capacitor to trigger the 30 second open circuit)
For the switching circuit: I have 5VDC from a Raspberry Pi connected to pin 2. On pin 3, I have it connected to the Collector side of an NPN relay, and the Emitter side is connected to a Ground pin on the Raspberry Pi. I have one of the GPIO pins connected to a 2kΩ resistor, which is then connected to the base of the relay