Lightning Strike - Serious Threat?

Hi ya Guys,

New to all this game and just in the process of getting set up. I have read many comments about lightning and am torn whether to include a ground wire or not. My anemometer will be fitted about 5ft above the roof apex on an aluminium pole and the weather station is a wired version. I am in the UK and don’t get too much lightning (maybe 1 or 2 per year?) but with the replacement costs of the gear I’m wondering should I?

Can I get the opinions of “the masters”

If you say yes - then can you also give advice on what materials to use.

The Glums :frowning:

If your anemometer is the highest object in your location, then I would consider treating the mounting as a lightning conductor. If you have other tall objects such as houses, trees, electricity poles / transformers near you, then the chance of you being hit is greatly reduced.

It is a percentages game really. Like you say, here in the UK, we don’t have the amount of storms as our overseas colleagues, so the chance of being hit is reduced, as the chance of lightning is a lot less.

If you are worried, then tie your mast down to ground. It wont cost much money, or take much time, but it will give you reassurance that should you take a strike, you should be OK.

Since we do installation of solar panels and equipment It best to ground your equipment proplerly. Not only is your equipment is at risk . Anything and everything that electrial is at risk. It better to be safe than sorry Ground it.

It’s a question of risk, but I wouldn’t worry about it too much. Whilst the numbers are dropping due to satellite and cable TV, millions of UK houses have had a metal TV aerial attached to their chimneys at the highest point of their roof for many years, yet you hear of very few problems due to lightning strikes on TV aerials. So I suspect the risk of you attracting a lightning strike is fairly low.

Whilst a direct strike is obviously worse, close lightning strikes can also cause problems. My closest experience with a strike was about 10-12 years ago. The roof of a garden shed 4 doors away was blown off by a strike. The shed was probably 20 feet lower than the house tops and all the TV aerials, but still got hit. The EMP (elctromagnetic pulse) generated current in various local wires, including my phone line and I ended up with a dead modem and hard disk driver card in my PC (which was connected to the modem/phone line). Nothing else in the house (TV or my amateur radio equipment) was damaged by the strike. The moral of the story is that lightning is so powerful that even if you take care to ground your metal pole and everything else in your house, if lightning strikes within 50-100 yards you might end up with fried equipment anyway!

For those advocating grounding…a question. Firstly, presumably you use very heavy gauge copper strapping? I assume most normal cabling available to the home market will fry under the currents induced by lightning long before it protects anything? Secondly, aren’t grounded metal poles liable to attract more lightning than an ungrounded pole? I thought that a grounded metal spike allowed a positive field to be generated around it which attracted lightning? I thought that one of the ideas of lightning conductors (with their heavy copper grounding straps) on high buildings was to attract lightning to the conductor which would hopefully take most of the strike to ground and therefore spare the rest of the building. Maybe this is an old wives tale, but I wonder if any lightning experts here know the truth. Perhaps by grounding things we’re adding to our risk?

one that i know is that the pulse/sruge.emf does not like to go around tight corners, and so a simple choke is simply wire wound and wound like a spiral…but the spiral extends like a coil spiral…the surge will then rather jump a gap to a grounded line than go through that choke… 8O

I have just emailed several specialist companies involved in lightning protection around the world asking for advice on what to do regarding bonding. Should I get any replies, I will post them here.

That’s an interesting question and one I was looking into recently. I found answers on the internet that said yes, no and makes no difference! I too would be interested in a definitive answer.


The higher the mast, the greater possiblity for a strike. IF you are worried you have several options. One would be to have the mast shorter than the highest object. ( get neighbor to put a rod on the far side of his house. Let his stuff fry)

The other to have your mast grounded and a rod on the far side of the house preferably else where. Take a look at the local radio/tv statiosn and see how they ground their towers, which are taller than what we have . They are metal, sunk into concrete and steel rods in the earth.

IF you are using a grounding, use thick copper wire and bury the rods deep enough, but if you do get a direct strike… see if your insurance can be modified to include your station.

Lightning may not like to go around sharp corners, but I think the EMP just radiates round the strike like a radio signal passing through everything. The surge induced by the EMP will go around corners…there were quite a few between the long (overhead) phone lines and my PC, but my PC components still blew :frowning:

I had a similar experience about 7 years ago. It was a strike nearby but it took out my modem, burglar alarm, telephone answering machine and several other devices.


[quote]prevention is feasible, and if chosen comes with a 25yr no-strike warranty.

the main issue is investmnt vs risk.

Hiya guys, sorry I’ve just caught up with all the replies and opinions. Unfortunately I am the highest house and my pole will tower above anything else. (Mmmm - must remember the local airport when I fit it!) I think I’m going to take a chance on the basis of no previouse damage to TV’s etc from lightning in the past. We always disconnect TV’s etc during lightning anyway and the missus won’t be best pleased with a wide copper cable running down the side of the house!

One last thought I did have was one of those extension power cables you get for use with computers - they sometimes have a phone or RJ45 connection(?) for surge protection do they not? Mines is a wired system so perhaps I could splice this in between the junction box and console to give that some protection (as probably the most expensive component)

Glums R Us :frowning:

of course my setup is wireless and unless a direct strike to the mast and station , the computer should be fine with the exception of EMF. I did get it added to my home owners insurance. They do that stuff for a fee here in Iowa.

I have all computers grounded through my UPS to the house ground. I definitely would ground the mast, anenometer, iss and whatever else just to be on the safe side. I would rather have my neighbors laugh at me (and they do…but I laugh back ) and have things grounded than perchance something does happen and even if it wouldn’t have made a difference on the outcome, it gives me piece of mind.

Just be very careful that you don’t touch any above or buried power lines, phone lines , gas mains, water pipes or fall off the roof in the process. Now that would make the neighbors chuckle until the flames hit their house,… but still… 8)

I hope you don’t normally have aircraft flying 10-20 feet above your roof!

It might help, but check what the device is designed to protect against. It’s probably supposed to protect against power line surges of a few tens or perhaps hundreds of wolts using metal oxide varistors (MOVs). These are fine for power line surges, but I doubt if they’d do much other than explode and then act as a spark gap if presented with a few million volts from a direct strike!

personally nothing is going to stop a direct strike or at least one near by from doing damage. The random chance is great. I would just do whatever makes me happy , gives me peace of mind and go on with life.

Hi All,

Another question about lightning:

I have mounted my anemometer on an old windsurfer mast, will a mast with high insulation properties make a difference?

Surely good old electricity would prefer choose the path of least resistance and strike my neighbours TV aerial. :slight_smile:

Or on the other hand could capacitance effect of the storm charge my pole up so that it becomes a very attractice target? #-o


Don’t forget that lightning usually comes with rain, and that mast is probably a pretty good conductor when wet, unless it happens to be perfectly clean and you are lucky enough to have de-ionized rain :slight_smile:

If you search the web it’s apparent there are many factors that determine the chance of a strike and it’s not yet a precise science. Unless you are in a very high lightning strike frequency area, or are erecting something significantly higher that anything else close by, it’s probably not worth to worry about.