Grounding for timber poles

[wisphopefull]

I'd appreciate advice from all (especially Chris) on this.

On one site I have a timber pole, there are then 3 metal brackets on that pole, the sectors and rocketdishes are then on the metal brackets.
The Rockets are grounded through the shielded RJ45 connectors.

We just had some nasty thunderstorms go through here for 16 hours but luckily everything on the pole was fine.

In future however is it safer to ground the metal brackets too?

I noticed a pic that Chris had from 2012, he had some metal brackets on a timber pole for an AF24 and PowerBridge, they didn't seem to be grounded except for the shielded RJ45.

[wayneorack]

Yes. Ground the brackets using heavy gauge copper wire. If the equipment is attached to equipment inside a building with copper Ethernet, ground the brackets to the building ground. If there is not an existing ground system, drive at least one rod and connect to it.

[Ant]

On timber poles around here, a heavy bare wire of copper is stapled from the ground rod to the top of the pole. Anything metal on the pole is then bonded to the ground wire.

[wisphopefull]

Is it not kind of a double edged sword when grounding those brackets though, it would make the brackets on the pole a low resistance path to ground so a direct lightning strike might then be more likely?

[wayneorack]

Yes, but the pole already has a lower resistance than air. The idea of a totally isolated system sounds nice, but that doesn't really work when you poke something 30+ feet in the air. The goal of grounding is to make the ground a lower resistance path than the electrical or communication system.

[lligetfa]

On timber poles around here, a heavy bare wire of copper is stapled from the ground rod to the top of the pole. Anything metal on the pole is then bonded to the ground wire.

Polyphaser has a white paper out on grounding wood poles. http://www.solacity.com/docs/polyphaser ... ection.pdf They propose two ground wires. One goes from the lightning rod down to the ground rod system and a separate wire goes from the topside equipment down the other side of the pole.

Also, instead of wire, I like to use the flat tape but with the price of copper and thieves, it is a lot more work to disguise so only practical where secure.

[wisphopefull]

So would it be safe to ground the metal brackets straight back to the shed girder or is it safer to go back to the AC mains rod directly?

Or if I put a ground rod at the pole, can it be bonded back to the shed girder or does it have to be direct to the AC mains rod?

I certainly don't want any electrocuted cattle.

[lligetfa]

Drive a rod at the pole and bond it back to the shed girder and also to the mains ground.

[wisphopefull]

Drive a rod at the pole and bond it back to the shed girder and also to the mains ground.

Since the mains ground is already bonded to the shed girders, isn't it sufficient to just bond the pole rod to the shed girders?

Thanks guys

[rebelwireless]

sufficient isn't something that can be generalized. What I mean is that if you have trees nearby that are higher than your pole, or you are lower than some nearby structure, 'sufficient' grounding has a lower requirement.

For wood poles, I prefer to do a primary ground (from equipment mounts to a driven grounding rod) and a separate ground for a lightning rod, run down the other side of the pole to a separate grounding rod. I would also bond the primary ground to the building ground to reduce/eliminate any potential between grounds.

Wood poles are 'easy' in this regard, because the pole is typically high resistance already, so a separate lightning rod is the primary isolation from a lightning strike Vs steel towers that the whole tower gets energized and you need to go the extra mile and ground at each leg etc. Usually* lighting only strikes wood during high humidity periods, so you should have a lightning rod but otherwise you'll be fine.