[TowerTalk] Fwd: Grounding of tower

[Jim Brown]

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