Anyone's gear actually been hit by lightning?

of course you have to connect an outdoor antenna mount to your standard earthwire. but all other kind of lightning protection in my opinion is nonsense. a real lightning protection needs three stages - and real equipment for this job costs more than 50 times what your pi costs. using wifi to connect to your network i think you are perfect save and worst case is 150$ damage of your pi with dongles, amplifier and sd-card :slight_smile:

You need to correctly ground. Anyone who gets directly struck is not trying to avoid equipment damage. They are trying to avoid the entire house burning down. I do know someone who got a direct strike. Everything electric related was destroyed, but the house didn’t burn down. You also need correct grounding to prevent a static charge build up. Static will damage your equipment and it only takes wind to cause it. No lightning required.

See the following link for a simple guide:
http://www.reeve.com/Documents/Articles%20Papers/AntennaSystemGroundingRequirements_Reeve.pdf

Yes. Best thing to do is disconnect and isolate.

hmmmm - i’d think every owner of a datacenter - and many other would disagree here :slight_smile:

[quote=“TomMuc”]

I’m talking about residential. If you would like to talk about commercial, we can. But that is not the topic. Hint, remove any voltage potential across the equipment during the strike.

lost an amplifier on one of our sites during an electrical storm his past summer. A direct hit would have been a bigger deal.

EVEN IF YOUR HOUSE DOES NOT HAVE AN ANTENNA, LIGHTNING CAN STRIKE.

THE DAMAGES SHOWN IN PHOTOS BELOW ARE CAUSED BY LIGHTNING STRIKE.

THINK OF PROTECTING YOUR HOUSE FIRST, AND PROTECTING YOUR RASPBERRY PI & DVB-T DONGLE LAST.

https://i2.wp.com/www.geekologie.com/2009/02/04/lightning-cow.jpg

In our domestic situations you can reduce the likelihood of a lightning strike but in the end, lightning will go where it damn well pleases! Commercial and industrial sites can of course build lightning arrestor towers and rods etc but these are well outside most of our means.

I’ve had some pretty intense electrical storms at my location without any side effects at all other than a short period of reduced range on my receiver setup, so I’ll stick with my current setup for now, just changing antennas and checking results as time permits.

Cheers.

**My setup:
8 element homemade colinear antenna made from quad shield RG6 F connector-> 5m RG6 quad → TV masthead amp → Power injector → 1m RG6 quad → 1090Mhz BP filter → Noonelec DVB rxer → Raspberry Pi B+ running Piaware.

Best distance so far: 475Km**

It will be nice if you post photos of your setup.

It is a good idea to try different types of antennas. For the comparison to be realistic, the test setup should be;
(1) with short length of coax (your setup already meets this condition).
(2) without amplifier, as by boosting the weak signals, amplifier can make a poor antenna to perform like a good antenna.

Hi guys,

This makes me slightly nervous…

I’ve just moved my antenna to the roof ridge, so it sticks up above the roofline.

My antenna feeds into an amp, with a power inserter powering.

The whole rig (Rpi, amp, etc etc) is run off a spur off the lighting ring in my attic, using 10amp cable.
Like all the rings, the lighting ring is terminated in the central house fuse box.

(I’m aware the lighting ring / fuse is low rated, so I wont be putting any heaters or high drawer items on it.)

When we say…

“of course you have to connect an outdoor antenna mount to your standard earthwire”

I take it that as the amp is connected to earth through it’s power supply (UK 3-pin plug), this is what we mean?

Is this adequate?

Of course, in my case, although the antenna is earthed (through the amp supply), the mount itself isnt…

Whats the simplest way to earth the mount itself?

the earth wire is the absolute must - and no insurance will ever pay anything without:

Suitable as ground conductors are:
– a single solid wire with a cross-section of at least 16 mm2 copper, at least 25 mm2 aluminium or at least 50 mm2 steel.

https://www.kathrein.de/fileadmin/media/content/07-Satelliten-%20und%20terrestrische%20Empfangssysteme/antenna_earthing.pdf

http://electrical-engineering-portal.com/lightning-and-surge-protection-for-cable-networks-and-antennas-for-tv-part-2

I wouldn’t be surprised if that wasn’t true - so much stuff is double insulated nowadays.

But then you’re in the UK and so many people have still got a TV aerial on the chimney, and that just has a connection to a TV in the living room, and no one worries.

There’s nothing wrong with putting a double 13A socket onto the lighting circuit - in fact it’s quite a common way to connect TV antenna amplifiers, if someone were to plug a device in that takes too much current a breaker would just trip. Just put a label on the socket to say that is is wired to the lighting circuit, maximum load 2A

I’d run an earth wire from the antenna shield to the earth pin on an otherwise unused 13a plug … just to protect the Pi from any static that might build up on the antenna.

Thanks PeterHR,

Good to hear from someone else in the UK!

The US specs seem pretty rigorous…

I’ve got a “pet sparkie” coming out to give me his thoughts soon, so I’ll let you know what he says.

Mainly worried about “burning the house down” and “nulifiying house insurance”…

I’ll take a look at earthing the antenna as you suggest tho.

As you say though, having cast on eye sky-ward on walking past other houses, TV antennas much higher than mine seem to have no additional protection…

C

I dont know how far this is true, but in any case, it is an interesting story. :slight_smile: :smiley:
Texas Bar Sues Local Church Over Lightning Strike
A bar called Drummond’s, in Mt Vernon, Texas began construction on an expansion of their building, hoping to “grow” their business. In response, the local Southern Baptist Church started a campaign to block the bar from expanding - petitions, prayers, etc. About a week before the bar’s grand reopening, a bolt of lightning struck the bar and burned it to the ground! Afterward, the church folks were rather smug - bragging about “the power of prayer”. The angry bar owner eventually sued the church on grounds that the church … “was ultimately responsible for the demise of his building, through direct actions or indirect means.” Of course, the church vehemently denied all responsibility or any connection to the building’s demise.

The judge read carefully through the plaintiff’s complaint and the defendant’s reply. He then opened the hearing by saying: “I don’t know how I’m going to decide this, but it appears from the paperwork that what we have here is a bar owner who now believes in the power of prayer, and entire church congregation that does not.”

I ran my coax to a grounding block and from there I have a #6 copper line going to a ground rod. I went a little overboard and bonded that one to a couple more around the property for extra protection. Figure the minimal cost of some protection can’t hurt. Lightening is a beast and no matter what you do, it can find a weak spot, unless you have an unlimited budget.

With the cost of copper down, go to a scrap yard and you can pick up the copper REALLY cheap right now. It’s a whole lot cheaper doing it that way than running to the big box Home Depot/Lowes.
Just my opinion and what I’ve done. The scrap yard is an awesome place to find goodies though.

1.1 Damage from Lightning
People generally think of lightning damage as what happens at the point where a cloud-ground stroke terminates on a tree, structure, or elevated wiring. This is generally called a lightning strike. Unless the struck items are protected from lightning, the results of the strike are often visible and lasting. But the lightning current pulse continues into conductive parts of thestructure, cables, and even underground wiring and pipes. Because the initial lightning impulse is so strong, equipment connected to cables a mile (1.6 km) or more from the site of the strike can be damaged.

Figure 2 shows four ways in which a lightning strike can damage residential equipment, in order of decreasing frequency of occurrence. The most common damage mode shown in Figure 2 (labeled 1) arises from a lightning strike to the network of power, phone and cable television (CATV) wiring. This network, especially if it is elevated, is an effective collector of the lightning surges. The wiring then conducts the surges directly into the residence, and then to the connected equipment. While not shown in Figure 2, lightning can also travel through the ground (soil), reaching underground cables or pipes. This is another
route for lightning to come into a building, and can also damage the cables.

The second most common mode (2) shown in Figure 2 results from strikes to, or near, the external wiring network common to most suburban and rural houses. Air conditioners, satellite dishes, exterior lights, gate control systems, pool support equipment, patios and cabanas, phone extensions, electronic dog fences, and security systems can all be struck by lightning, and the lightning surges will then be carried inside the house by the wiring.

As shown in Figure 2, lightning may strike nearby objects (trees, flagpoles, signs) that are close to, but not directly connected to the house (mode 3). In this situation, the lightning strike radiates a strong electromagnetic field, which can be picked up by wiring in the house, producing large voltages that can damage equipment.

Finally, Figure 2 shows (mode 4) a direct lightning strike to the structure. This type of strike is very rare, even in high-lightning areas. It can severely damage a structure without a lightning protection system (LPS), and will generally damage most electronic equipment in the house. The structure damage can normally be prevented by a properly installed LPS of Faraday rods and down conductors, but the LPS alone provides little protection for the electronic equipment in the house.

1.2 Enhanced Protection against Lightning
The NEC/CEC allow for increased protection in high-lightning areas by the optional installation of the following:

  1. A lightning protection system (LPS);
  2. Surge protectors on the AC power wiring;
  3. Additional surge protectors on signal wiring;
  4. “Supplementary protection” (also called “Point-of-Use” protection) at the equipment to be protected.

Figure 4 shows schematically how the first three above are installed.


Although the lightning protection system is the most visible improvement, it is only useful in the extremely rare direct strike scenario, such as in mode 4 of Figure 2. The basic elements are shown in Figure 4. The lightning strike attaches to the tip of the air terminal, and the lightning current flows via the down conductors into the lightning ground system, which is bonded to the building ground. Properly installed systems should be undamaged by even the largest recorded strikes. They should, however, be inspected periodically to assure that mechanical damage has not occurred.

The design and installation of the lightning protection system is not described by the NEC, but by a related document, NFPA 780-2004. Fortunately there has just been a major recent revision to this code, with strong improvements, especially in requirements to install surge protectors to protect the electrical and electronic equipment inside the house. The new code recognizes only passive strike-terminating devices such as metal rods and heavy wires.

AC and signal surge protectors at the building entrance (items 2 and 3 above) serve similar purposes. They collect the major part of the lightning surge currents coming in on external wiring, and direct them harmlessly into the building ground. They also limit the surge voltages that get inside the building, and greatly reduce the burden on the point-of-use protectors, at the equipment.

The effectiveness of this protection system depends on the integrity of the building wiring. A good surge protection system installation should include testing of all the receptacles to be used, for correct connection of the line, neutral, and ground. This should be done using a tester which can detect interchange of the neutral and ground connections, a common problem. Incorrectly wired receptacles can often appear to function normally, but may not allow point-of-use protectors to function properly.
Most new houses are built with power, phone, and CATV entry points close to one another. That is very desirable, and makes it easy to mount the AC protectors and signal protectors close to the main building ground point (Figure 4).

If wiring comes into a building at many different points, it is much more difficult to get proper protection against lightning surges. Even if surge protectors are installed at these alternate entry points, the long ground wires running back to the main building ground greatly reduce the effectiveness of the protectors. In high-lightning areas, where lightning protection is a major concern, it is worth routing as many AC and signal cables as possible past the building power entry point, to
facilitate good grounding for protectors and cable sheaths.

The coaxial cables carrying CATV signals and small-dish (DBS) satellite signals are often the path for damaging lightning surges to enter the building. For CATV cables, the code-required bonding of the sheath to the building ground is frequently omitted. For the satellite systems, the NEC/CEC require bonding of the antenna mounting hardware, as well as the incoming cable sheath, to the building ground. This is often difficult to do. If the incoming CATV or antenna lines can be routed to a distribution closet near the AC service entry point, the required bonding can be achieved.

SOURCE:
How to Protect Your House and Its Contents from Lightning
IEEE Guide for Surge Protection of Equipment Connected to AC Power and Communication Circuits

IEEE = Institute of Electrical and Electronic Engineers of North America.
NEC = National Electrical Code of USA

THE DIFFERENCE BETWEEN LIGHTING PROTECTION OF BUILDING AND SURGE/LIGHTNING PROTECTION OF ELECTRONIC EQUIPMENT

Lightning protection systems - What they do and don’t do
A lightning protection system’s only purpose is to ensure safety to a building and its occupants if lightning happens to hit it directly, a task accomplished by providing a good, safe path to ground for the lightning to follow. Contrary to the myths, lightning protection systems:

– Don’t attract lightning
– Don’t and cannot dissipate or prevent lightning by ‘draining’ a storm of its charge
– Most don’t offer surge protection for sensitive electronics
– Do offer fire protection and structural damage protection by preventing a hot, explosive lightning channel from passing through building materials.

How a lightning protection system works

Unprotected Structure - Without a designated path to reach ground, a lightning strike may choose to instead utilize any conductor available inside a house or building. This may include the phone, cable, or electrical lines, the water or gas pipes, or (in the case of a steel-framed building) the structure itself. Lightning usually will follow one or more of these paths to ground, sometimes jumping through the air via a side flash to reach a better-grounded conductor. As a result, lightning presents several hazards to any house or building:

Fire- Fire can start anywhere the exposed lightning channel contacts, penetrates or comes near flammable material (wood, paper, gas pipes, etc) in a building - including structural lumber or insulation inside walls and roofs. When lightning follows electrical wiring, it will often overheat or even vaporize the wires, creating a fire hazard anywhere along affected circuits.

Side flashes - Side flashes can jump across rooms, possibly injuring anyone who happens to be in the way. They can also ignite materials such as a gasoline can in a garage.

Damage to building materials - The explosive shock wave created by a lightning discharge can blow out sections of walls, fragment concrete and plaster, and shatter nearby glass.

Damage to appliances - Televisions, VCRs, microwaves, phones, washers, lamps and just about anything plugged into an affected circuit may be damaged beyond repair. Electronic devices and computers are especially vulnerable.

Adding a lightning protection system doesn’t prevent a strike, but gives it a better, safer path to ground. The air terminals, earth conductors from air terminals to earthing rods, and ground rods work together to carry the immense currents away from the structure, preventing fire and most appliance damage.

Single protection

Multiple protection

Single protection is cost effective, but still there is substantial chance of damage by lightning bolt. There being only single conductor to earth, a substantial part of lightning bolt may still pass through building structure.

With Multiple Protection System, there is very little chance that any appreciable part of lightning bolt will go through building structure. This is due to the fact that there are enough number of parallel paths provided by large number of lightning rods, copper down strips/wires and earth rods, all bonded together at roof level as well as ground level.

Lightning and Surge Protectors / UPS Devices
Surge protectors and UPS units are not suitable lightning protection devices. These appliances provide some degree of protection from voltage spikes from everyday power surges and distant lightning strikes. But when lightning strikes a structure directly or very close to it, lightning protection system or not, all bets are off.

A common surge protector simply cannot have any effect on the violent, catastrophic burst of current from a very close or direct lightning strike. Direct lightning current is simply too big to protect with a little electronic device inside a power strip, or even a hefty UPS unit. If your UPS or surge protector is in the way of the lightning’s path, all or part of the lightning will just flash over or through the device - regardless of the amount of capacitors and battery banks involved.

Even ‘disconnects’, or devices that physically switch off power to a device by activating a set of contacts, will not guarantee protection. A small air gap will not stop a lightning bolt that has already jumped across miles of air. It won’t think twice about jumping a few more inches, or even a few more feet, especially if the ‘path of least resistance’ to ground is across the contacts of the disconnect switch.

SOURCE (Except two images above and their associated write up):
http://stormhighway.com/protection.php

Thanks for the info abcd, it’s a great help for anyone confused about the working of lightning protection.

Cheers,

Goldy

In Australia it would be deemed as an “Act of God”. :wink:

My set-up (the RPi antenna isn’t in this old photo but the set-up is still the same just with a coax coco that has been sealed) has zero lightning protection, though have had a few very close strikes during the time I’ve had the FR24 and RPi running.

Both FR24 and RPi is connected to an outdoor powerpoint, with a “weather proof” box housing the boxes. The FR24 box is connected using an ethernet cable running inside to the ADSL router (not ideal) and the RPi connects using WiFi.

Filmed on Sunday
https://www.youtube.com/watch?v=lWCaxAo9rzg)
There were closer strikes I didn’t get, first one is around 3km away and the other was 1.3km.