Do I Need to Ground a Metal Weather Mast?

Greetings Douglas,

I'm installing a weather station on metal pipe mast on roof gable/rake. The weather station is self-contained, battery powered, WiFi linked to indoor display console, not connected to the home electrical system.

What are best or ok options for lightning protection: (a) do nothing; (b) bond mast directly to home electrical grounding rod with wire; (c) bond mast to separate isolated grounding rod; (d) bond together two ground rods; (e) other? What gauge wire, insulated or bare, should I use?

Thank you, F A

To a storm cloud, your mast on the roof is a lightning rod. As such, to protect your house, the lightning rod needs to be grounded. I've seen lots of lightning damage; doing nothing to prevent lightning damage is not a good idea.

As far as the other options you listed, though, there might be local electrical code variations that have to be complied with. Even though "Codes" are listed in the National Electrical Code (a publication of the National Fire Protection Association {NFPA}, a non-profit organization), your state and local governments often make variations to the "Codes". (After all, it's the government that makes the rules we have to live with.)

To get a better idea of what can and should be done, before putting up the mast, I suggest you contact an electrical contractor in your area who knows the "Code" and the local laws.

Might I also recommend some sort of solar charging system for the batteries? As you describe it now, there isn't a charger for the batteries. Changing the batteries might become a little cumbersome after a few times. A properly installed solar charging system will greatly reduce the need to change the batteries.

Douglas Krantz

Greetings Douglas,

Good idea about the solar charging. I will definitely look into that.

Regarding code compliance of the grounding, I'll check with an electrician. My state (Maine) has adopted and follows the 2017 NEC and is in the process of implementing the 2020 NEC, and my small rural town does not have any additional requirements of its own.

As an additional piece of information, I'd love to hear what you believe is "technically" the best approach, which I can then propose to the electrician.

Thank you, F A

I'd suggest using the ground rod that's in the ground already. Using that is cheaper, and also a more-sure electrical ground.

Second choice is a second ground rod that's bonded to the original ground rod. The electrician can explain that also. More expensive, but you may want to go that route for esthetic reasons.

Douglas Krantz

Greetings Douglas,

Thanks for your further technical advice. I appreciate it.

Thank you, F A