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Dear Guys,

I am planning to connect a fire alarm system with cable 1.5mm cable to the security system which require cable 0.8mm with the help of relay.

Is it really possible to do this with the help of relays. We only require one input from the fire alarm system so as to activate the security system.

Kindly help in this matter.

The size of the cable is not important here. The main reason to use relays would be if each system used a different voltage. For eample, if the fire alarm signal was 24 volts dc and the security system expected 12 volts ac, or perhaps just a switch closer, then a relay could be used. For this example you would pick a relay with a 24 volt dc coil and then connect the relays contact to the security system input. If the input expected 12 v ac input and had a 12 v ac "hot" connection, then connect the "hot" wire to the relay common contact and a wire from the relay normally open (no) contact to the security input. Just match the relay coil voltage to the fire alarm signal output.