Electrician

This is one of the most commonly asked questions in FAQ forums about electricity and wiring.
It must be understood that new appliances will be designed to meet the newest standards.
It is not reasonable to expect someone to rewire their home because they need a new dryer or range [stove]!
According to the NEC [National Electrical Code], it is now required to isolate the neutral conductor from the appliance frame or chassis.
It used to be allowable to use the neutral as a grounding means by incorporating a link between the neutral and the chassis.
The problem with this is that, should the neutral become "open" at some point, the chassis or frame then becomes energized!
The answer to this safety issue was to require a separate grounding conductor in the cable feeding the appliance.
The NEC allows the replacement of the new four prong cord with a three prong cord for appliance replacements in existing installations only!
It is then required, when the cord is thusly replaced, to establish the frame grounding link from the chassis to the neutral.