[TowerTalk] Grounding of cables to tower?

[Jim Brown]

On 10/18/2017 5:41 PM, jimlux wrote:
> h, the fine problem of the meaning of words in different contexts - in 
> Electrical Code land - bonding could well be done by the coax shield, 
> with a couple potential problems:
>
> 1a) You'd have to make some reasonable case about what a plausible 
> fault current might be - this is the beauty of Class 2 Energy Limited 
> devices (your doorbell)- the maximum fault current is quite low, so 
> almost anything works. If you're running coax to something also 
> supplied by an AC power cord, it's a bit trickier. Probably would 
> depend on the fusing or overcurrent protection of the power supply.

There are two other issues related to power. Code requires that the 
equipment  ground (green wire) be run with the phase and neutral 
conductors. First, if the equipment ground for the power system and the 
phase conductor don't follow the same path, a fault (phase shorted to 
ground) forms an inductive loop, the impedance of which can delay the 
operation of the circuit breaker or fuse. Second, if the separately run 
equipment ground is broken by some failure, the equipment is no longer 
protected. This is equivalent to what you had noted with  "unplugging 
the coax."

73, Jim K9YC