Over the years I.ve heard many theorys on lightning protection . A grounded protector at each end. Protector at each end grounded only on ksu side. Shielded cabel grounded at both ends or grounded at only one end. Whats your thoughts ???
Thanks Gary S.
Gary, the jury is still out on this subject. The reality is that you have to abide by the requirements set forth by the NEC nearly everywhere in the country. They basically require that you bond the cable's sheath via an approved clamp to the protector and to the building's grounding electrode conductor. The same stands for CATV and other utilities and has actually been that way for many years.
Generally, it isn't a bad idea to follow the standards that the LEC uses. They have a huge investment in their installed plant, so they do it correctly in order to minimize the risk of damage/outages to their networks.
Then again, you have the issue of tying the grounding systems of different buildings together and using the cable's sheath to accomplish this. That is probably where your question comes into play.
An friend of mine who is a retired Bell System cable guy always encouraged me to throw a piece of #6 copper in the same trench with the cable to tie the buildings' GECs together, thereby offloading the potential that could ride on the cable's sheath. In a perfect world, that would be a great idea, but #6 copper in a competitive bidding environment is expensive.
Aerial cable ties are a bit easier, since the support strand (albeit galvanized steel) gives you a good means to accomplish this inter-system bond with minimal effort.
In any event, yes: The cable's sheath must be bonded at each end and protection (primary and secondary protection must be provided at each end as well. Most supply houses only sell secondary protection devices that 'look' like the real thing. You have to buy primary protection from real supply houses and be prepared to pay for it. Doing it right isn't cheap.
Thanks Ed. Just wanted others imput.
Gary S.
Thanks Ed. Just wanted others imput.
Gary S.