Traffic Signal Poles Incorrectly Grounded
No wonder so many traffic signal poles are incorrectly grounded!
This is from the proposed International Municipal Signal Associations.
8.9.5 Grounding of Support Poles
The inspector must ensure that all support poles have been properly grounded
(what does this mean) and that the required length of ground rod has been installed (what
is the required length, and why would we drive a ground rod anyway?). For span wire
installations, the catenaries and messenger wires should also be connected to the pole
grounding system (what is the pole grounding system? The ground rod?). However,
the pole grounding system should not be connected to the cabinet grounding system (You're
joking right?). Keeping the two grounding systems separate makes it more difficult
for lightning strikes to travel down the pole and into the cabinet (So we are worried
about lightning damage to the cabinet equipment, but not protecting the general public
from electric shock! What's wrong with proper surge protection for the cabinet equipment
and proper bonding of the metal parts to clear any line-to-case faults?)."
Mike Holt's Comment:
This drives me crazy. Civil engineers designing electrical systems and they have
no clue what they are doing. They think sticking something in the ground makes it safe/grounded!
Imagine any organization suggesting that the metal poles and cabinets not be connected
to an equipment grounding conductor to clear line-to-case faults.If you have any comments
or feedback, please let me know, Mike@MikeHolt.com
Copyright © 2003 Mike Holt Enterprises,Inc.