I have been brewing for a few years with a 3 wire system running 2 5500 w elements with the ground connected securely to the keggles. No GFI just a few 40 amp breakers , ssr's and 2 pids. I am still alive and my system works great and I am very confident about it. If your brew pots are grounded, are you safe ? Do you really need a GFI breaker ? I am no expert on this but I am familiar with 220 volt 3 wire . I have a hardwood floor business and all my sanders are 3 wire and run safe. I understand that brewing pots are full of liquid but if they are grounded then isn't that enough ? Is a GFI breaker really just a safety seat ?