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DISCUSSIONDISCUSSIONGGcrossover wiringsurgeprotectorGsurgeprotectortransmitterGsurgeprotectorinstrument panel 1outdoorindoorgroundincreased groundpotentialgroundingresistancesurgecurrentoutput cableGsurgeprotectorinput cablepower cablepowercablelightning surgeGGsurgeprotectorcomm.deviceinstrument panel 2groundGsurgeprotectorGGcrossover wiringsurgeprotectorGsurgeprotectorreceivinginstrumentgroundsignal cablepower cablelightning surgeG21Recommended models: • Model MDP-24-1 (4 – 20mA DC signal lines) • Model MA-100 (100 –120V AC, 2A power supply) • Model MA-200 (200 –240V AC, 2A power supply) • Model MAX-100 (100 –120V AC, 5A power supply) • Model MAX-200 (200 –240V AC, 5A power supply)QUESTIONA control room instrument was damaged during a recent lightning strike. Why?If possible, determine exactly where the lightning entered the instrument. In all proba-bility, it entered through the input signal line or power supply line.We would recommend that you use a surge protector on both the signal and power supply lines. Contact your local sales office for specific models for your application.3ANSWERANSWERRecommended models: • Model MDP-24-1 (4 – 20mA DC signal lines) • Model MA-100 (100 –120V AC, 2A power supply) • Model MA-200 (200 –240V AC, 2A power supply) • Model MAX-100 (100 –120V AC, 5A power supply) • Model MAX-200 (200 –240V AC, 5A power supply)QUESTIONA transmitter that is attached to a panel located indoors was damaged by a re-cent lightning strike. Can you explain why this occurred?Signals and power sources are commonly connected to a transmitter through outdoor cable pits and conduit pipes. It sounds like the lightning surge damaged the transmitter by means of these lines. If the transmitterʼs output is sent outdoors, then install surge protectors to protect the input, power and output lines. When a panel 1 located indoors works, ground potential for only panel 1 is elevated and it causes potential difference with the panel 2 which is grounded separately at a differ-ent place. When panel 1 and 2 are grounded separately, set a surge protector on the cable to connect panels even when it is wired indoors. 4ANSWERANSWER

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