On 5/11/2013 4:51 AM, K1TTT wrote:
The only real reason for requiring ground rods for electrical distribution
is because one part of the system is grounded, so if there was a fault and
your house entrance wasn't grounded you could have a shock hazard between
anything plugged in and the local earth. At least if you have ground rods
the electrical system ground will be closer to local earth potential, even
if that is not at 0v with respect to a distant ground.
Actually it's the other way round -- an earth connection is required for
LIGHTNING protection. The NEUTRAL is bonded to ground at the entrance
panel so that one part of the system will be at ground potential, and
the GREEN WIRE is carried so that a short to a chassis will blow a fuse
before someone is killed by touching the hot chassis and a grounded object.
There's another major issue with using anything but neutral to carry the
return current -- doing so establishes a large magnetic field, because
the loop area is large.
Note that the single wire systems Jim and Jim have described are very
specialized DISTRIBUTION systems -- that is, for use by the POWER
COMPANY. They are NOT permitted for premises wiring, because they are
DANGEROUS, for the reasons noted.
73, Jim K9YC
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|