sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Outside Plant OSP Construction Should messenger strands be grounded for lightning protection?

Hello all,

I have hundreds of feet of copper wire lashed to 1/8" steel messenger strand running through poles and trees. This is a private plant on a forested land and there is usually no primary or secondary power lines above the comm space.

We often have lightning strikes on trees. I have seen lightning jump from one tree to another via a steel cable before (killed both trees).

I have put protection on phone cables entering buildings but I am wondering if I should ground the strand so that lightning is diverted to ground rods instead of following phone cables. And if so, at what intervals should I put ground rods.

Does that make sense? What is the practice? I haven't seen this mentioned in RUS bulletins.

TIA

Bruno, yes you should ground those wires.
Here NYC we don't do that, very little exposed cables.
I'm sure someone will follow who can point you in the right direction.

I found this with a google search. I didn't read it so don't know if it will address your specific issue or not.

Yes the strand should be grounded at each end with #6 copper ground and a 10ft copper ground rod. I don't remember the intervals at which this was done, but I do remember bonding to the power ground, it may have just been where it was available. I really don't recall the B.S.P on this. I kind of recall at one point the practice changed to where we didn't bond to the power ground, but I'm not positive about that. I do remember having "hot" grounds a few times when the ground wire to the ground rod was broken on power poles. We were required to test the ground wire prior to climbing a joint use pole.

Here is my google search if it helps.

The NESC, which is the OSP foreman's Go To reference has specific rules regarding telephone cable strand bonding. Rules 096, 097G, 344, 354, 384C for starters.

The rule of thumb and supported by the NESC is every 1/4 mile the strand must be bonded and grounded. Look Here

Rcaman

Thanks gentlemen for all this helpful information.
I'll get a few ground rods and a jackhammer.

You don't need a jackhammer. You can use a hammer drill, with a 1/2" socket wrench extension, plugged into an expendable 1" socket. Put the extension into the chuck of the drill, and put the socket over the end of the ground rod. Set the drill motor to "hammer only" and voila.

When the rod is almost at the correct depth, fasten the ground wire and clamp to the rod, then pound it the rest of the way, so that the clamp is below grade. This protects it from dog pee, lawn mowers and vandals.

Good idea. Thanks!
Also I've read fence post drivers work well for this, especially useful when no power is available.

So does a sledge hammer and elbow grease...

-Hal

Using a post driver will work if the ground is not real hard. If it's really hard dry clay or real rocky you'll just bend it. I've used them and they work pretty good. Mostly just a 3 lb hammer and elbow grease as Hal said.

Nobody trusts me enough to hold the rod while I wield the hammer.
They must know something that I don't.