Interpretation #7957

The extensions would be allowed per the existing building code. The extension can not tell whether the ground and neutral are tied together at the service or the panel. GFCI and Arc fault breakers will still work if the panel will accept them. If it won't then a new subpanel would need to be installed that would still have a 3 wire feed. What happens in real life if someone needs to add a receptacle is they will do it on their own or have a friend do it in a manner that may not be code compliant or safe when they find out the cost of a panel replacement with new 4 wire feeder and most often a new service.