P6KE12A is a very good TVS (Transient Voltage Suppressor ) Diode that can be fixed across the power supply lines to block the transients. It is rated 600 Watts and protects the sensitive electronic devices from the voltage spikes induced on circuit. It can handle up to 12 Amps current. Ideal device to attach across, Telephone lines, Cable TV lines, Transformer power supply etc. It works like a simple Lightning Arrester.
TVS Diode operates by shunting excess current when the induced voltage exceeds the Avalanche breakdown potential of the Diode. It works like a Clamping device, suppressing all over voltage above its rated breakdown voltage. When the transients is over, the diode reset back to its normal position.
Connect like this