Insulation of electrical power pole

finsends · Oct 3, 2023

Hello,
I have a fairly big property and to get power to the house, there are several metal poles with the cables running along them.
I had multiple issues with lightning strikes and suspect that the lightning hits one of the poles and reaches the house through that route.

Additionally, the negative wire has no insulation. Does a lightning even care about the insulation on the cable? On the poles along the road, I saw these big insulators between cable and pole. Is it necessary to but those between the cable and the pole, because right now, the cable directly touches the pole.

Thank you for your answers.

James · Oct 3, 2023

Some pictures would help here.

Avo Mk8 · Oct 3, 2023

Looks like you are having a tough time of lightening strikes there in Cost Rica!

https://news.co.cr/thunderstorm-in-costa-rica-delivers-0-11-percent-of-global-lighting-strikes/7580/#:~:text=The%20majority%20are%20cloud%20lightnings,detection%20devices%20and%20satellite%20optics.

The big insulators you see on other poles may be there because the cables are carrying a higher voltage than your normal supply. Where I am in the UK the 230V overhead supplies in the street do not have discernible insulators for the overhead cable, which admittedly has all conductors insulated.
As you suggest, I don't think lightening cares much about insulation on the cable, particularly for direct strikes!

There are probably things you can add to the electrical installation in your house to protect appliances / electronic equipment etc. Best method is to unplug things when there's a storm!

We are very lucky in UK as lightening activity is significantly less here than in Europe, and much much less than eg Florida and where you are. So suggesting what we typically do may not go anywhere near what you need!

finsends · Oct 4, 2023

James said:
Some pictures would help here.

Will make photos tomorrow. Only of the poles or anything else?

finsends · Oct 4, 2023

@Avo Mk8
Thank you for your answer. Yes, I unplug all devices that are easy to unplug. A few days ago a lighting fried my solar inverter. I can't always unplug that. The 2 AC phases going into the inverter have a 100A breaker, which always is turned off. Could such a machine be protected from lighting if I put an AC breaker on the negative also?

So you think, the only option are these Surge protectors? I grew up in Germany and we never had any Problems with damaged devices. My parents run a solar system since 13 years and never had an issue, so I'm trying hard to find an error, which might cause all those problems.

Avo Mk8 · Oct 4, 2023

finsends said:
@Avo Mk8
Thank you for your answer. Yes, I unplug all devices that are easy to unplug. A few days ago a lighting fried my solar inverter. I can't always unplug that. The 2 AC phases going into the inverter have a 100A breaker, which always is turned off. Could such a machine be protected from lighting if I put an AC breaker on the negative also?

So you think, the only option are these Surge protectors? I grew up in Germany and we never had any Problems with damaged devices. My parents run a solar system since 13 years and never had an issue, so I'm trying hard to find an error, which might cause all those problems.

Surge protectors are definitely a good idea. It would be best to get local advice from someone who knows about protective devices, and for them to look at your installation and decide the best type of protection and where to put it.

Also I'm not sure adding breakers will help. Surge protectors seem the more obvious move.

James · Nov 21, 2023

some input from a local company that has experience in lightning protection is the best way forward in my opinion.
just adding isolators or circuit breakers, or even surge protection may not make any difference if you are regularly having direct strikes to your local supply cables.

remember, lightning has already travelled several miles through the air to get to the item it initially strikes, adding a switch or circuit breaker that has a 3mm (1/8th inch) gap between contacts is not going to stop its relentless journey to the mass of earth (ground) via any means it can find.

pc1966 · Nov 21, 2023

finsends said:
Could such a machine be protected from lighting if I put an AC breaker on the negative also?

No.

Lightening takes place in a few microseconds, a breaker at best in a few milliseconds. Around 1,000 times slower.

Surge protection devices are designed to operate fast enough (provided cables to them are short and direct) but there is a whole lot of work involved in making them protect you if you are getting direct or near-direct hits. As mentioned above, you might be best to speak to the power company or a professional in your area that does this type of work.

If you are interested this catalogue / infomecial has a lot of information on protection but mostly intended for professional guidance (about 16BM download):

https://www.nvent.com/sites/default/files/acquiadam/assets/E907W-WWEN.pdf

Most of it is about Lightening Protection Systems for buildings, and related earthing. But chapter 17 covers SPD.