Chris Lewis wrote:

This is slightly better than unconduited 3-wire, in that you
have better connections to the ground. However, if the neutral
separates in your panel or on the pole, the frame of your stove _still_
goes hot. The problem is that the frame is connected to the device neutral,
not how well it's connected to the system ground.

Because the fact of the matter is, if your neutral separates in the panel,
AND if you have a neutral-ground interconnect anywhere in your house,
_every_ grounded object in your house can potentially go to damn close to
line voltage. By NEC rules, ground electrode conductivity is not necessarily
high enough even to trip a 15A breaker, let alone the mains.


That happens anyway if the service loses its neutral; the bonding screw
at the service disconnect panel will energize all the grounds in the
house. I think that's why the power company takes it so seriously if
you call them and say your service seems to have lost its neutral.
(that plus the risk of fire from one leg operating at too high a voltage.)

-Bob