Ah, I don't think the thousand volt thing is accurate, you aren't grounding the spark plug wire, which is essentially on the secondary side of the magneto. You are grounding the low voltage primary side of the magneto and that certainly doesn't have thousands of volts on it. I've been using the RCATS 100X switch for a number of magneto engines. No problems at all. It is essentially a relay and a signal from your receiver closes the contacts and shorts the magneto input to ground.