RE: Getting a mains isolation transformer with a floating output is a=20 good idea if working on mains powered gear both to reduce the risk of damage to equipment and=20 to reduce the risk of shock to yourself. I used a heavy duty isolation transformer for about ten years. It brings=20 its own problems. It is an invitation to ground loops and leakage sometimes causes erratic=20 scope indications. When I moved to this location I chose not to install it. All three wire=20 line connections need to be in place to assure Safety and predictable operation! Whatever it takes, primary power distribution is not negotiable, it must=20 be correct! --=20 John Ferrell W8CCW "The man who complains about the way the ball bounces is likely to be the one who dropped it." =20 --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .