[TowerTalk] conduit

[Nick Pair]

I have mentioned the conduit and its ability to choke current in grounds(which you don't want to happen ) and coax etc. (which you do want). Others have reminded that the outer braid/corrugated jacket of the coax should be grounded just above the point where the coax changes direction from down to horizontal. The conduit forms a one turn choke coil around the conductor. It does not lower the voltage and lessen the jumping power of the strike, it just limits how much damage it can do. Its still way, way above the lethal level.
  On telephones, they are the number one cause of injury by lightning. The spark gap protectors the phone co. uses are really only good for static bled off. Even the newest ones using the current name of customer interface box aren't much better and won't prevent death by phone.
  The two required rods at your service entrance are not sized for lightning protection just for fault current due to short circuits. The largest wire required is a AWG #6 because that's all the short circuit current a rod can dissipate in average soil. This current is not the 200 or 400 amps your service is rated at, but the short circuit current the utility transformer can deliver. This can be 10k amps or better fro a short duration. Utilities also require this ground in addition to the ground they use at pole on bare conductor neutral in triplex drop wire.
  The NEC and NFPA have separate sections for grounding and lightning protection.
  A copper water service pipe does not meet the NEC requirements for the tying together of your ground systems and would require a appropriately sized wire with no problem with the wire snaking its was around any obstacles. Common sense tells us that your straight run with UL approved connections would be more that adequate in this case of a existing installation.
  In the case of a lightning developed square wave there would be a lot of harmonically related RF generated. Think of that switching power supply in the computer you are using and how much engineering went into quieting it down to a level you can barely accept.
   
  Well my 2 cents are up, 73
   
  NIck 
  WB7PEK

 				
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