So why are there warning balls on electric power lines?

Driving around here in Sunny Portugal we’ve become a little puzzled.

So, high energy – voltage? – power lines have little balls on them. Different colours, red and white perhaps. OK, that’s fine, it’s obviously a warning. “Here be high voltage power lines.”

And it’s on the top strand of the set going from pylon to pylon. That’s fine.

Could be for birds I guess, something that scares them. Maybe planes? Dunno, but that’s not the question.

Observation (two incidences, you can tell we’re doing science here) says that these balls are only on that line when the lines cross a road. But they’re far too high up to have anything to do with the road. The spans away from the road don’t have the reflectors/birdscarers/whatever on.

So, err, why?

33 comments on “So why are there warning balls on electric power lines?

  1. Just a guess – how about to stop small planes doing emergency landings on that bit of road?

  2. TMB probably has it.

    Balls on lines in US are usually large, and are definitely a warning to low flying planes.

  3. https://www.insideedison.com/stories/what-are-those-balls-that-hang-on-power-lines

    Have you ever seen those big yellow, orange, white or red balls hanging from power lines and wondered what they’re used for?

    They’re called visibility marker balls or marker balls. You’ll often find them near mountain passes, in the deep valley areas, near major freeway crossings and around airports. They weight about 17 pounds each.

    The marker balls are placed on power lines to make the conductor crossings visible to aircraft. Helicopters and small aircraft often fly low in mountain passes or freeways and usually fly low while approaching an airport.

    When you are flying, the conductors and skyline become almost invisible against the terrain — especially the skyline wires.

    Many of the marker balls are required by the Federal Aviation Administration, like the ones near airports.

    Over the years, Southern California Edison has also identified areas that are particularly hard to see.

    Next time you’re driving past a marker ball, remember that they’re used for the safety of the flying aircraft and to protect the electrical infrastructure.

  4. “It’s an attempt to interest the birdlife in learning to use an abacus.”

    Or an attempt to help Diane Abbott with her maths….

  5. Rather than (or as well as) deterring emergency landings, my guess would be that it suggests that Portuguese pilots of small ‘planes tend to navigate by following roads.

  6. Flying below 500′ in the UK is generally forbidden I believe, or rather, closer than 500′ in any direction to a person, vehicle, structure etc. So aircraft should be well away from and above power lines..

  7. They also reduce bird mortality. Apparently DEFRA is agin ’em because they say they are visually obtrusive (duh!) and they’d rather have a few helicopter crashes than spoil the scenery. How they intend to reduce the visual obtrusiveness of a string of great big fuck-off 400kV pylons is left unexamined.

  8. Off topic: the Daily Mail seems to have noticed there is something wrong with the Life boast. Interesting that they are putting it down to too much cash – which I don’t think will be a problem for long – and a culture clash between the middle class scum who administer the working class lads who do the work:

    http://www.dailymail.co.uk/news/article-5719757/amp/Britains-heroic-lifeboat-volunteers-drowning-sea-political-correctness.html

    For lifeboat crews, the biggest recent change (and a key factor in squabbles) has been a ‘restructuring’ of middle management last year by a senior executive called Leesa Harwood, formerly of Save The Children, who was hired as the RNLI’s ‘community lifesaving and fundraising director’ on a salary of about £95,000

    I think I can see what went wrong. This is also a conflict between the Rough Men who get things done and the Woman Demanding Fainting Couches who have been foolishly raised above the men.

  9. I’m sure it is for aircraft.

    Following roads (on the right) is a useful navigation technique so identifying cables is a wise precaution.

    As an aside, my flying instructor taught me not to use a road as an alternate landing spot in an emergency on the basis that cars tended to plough into you once you had got it safely down.

  10. “Rather than (or as well as) deterring emergency landings, my guess would be that it suggests that Portuguese pilots of small ‘planes tend to navigate by following roads.”

    On my first trip in an Army Air Corps helicopter I was surprised to find the pilot had an AA route map in his map pocket. But it made sense after I’d thought about it.

  11. My mate’s dad was an undertaker. He saw some pretty horrific deaths, as undertakers do. He reckoned the worst was parachutists and hang-gliders that hit high voltage electric lines.

    Lines are all marked, and pilots should check them on their flight plans.

    In NZ it is often helicopters and planes doing low level top dressing passes. It’s easy to get a bit lost when you are buzzing hills that low.

  12. So much for my theory – when a very young child – that it was to help the cables float if floods came.

  13. Next time you’re driving past a marker ball, remember that they’re used for the safety of the flying aircraft and to protect the electrical infrastructure.

    Next time you are driving past a marker ball, pay no fucking attention to it and instead focus on the bloody road!

  14. “On my first trip in an Army Air Corps helicopter I was surprised to find the pilot had an AA route map in his map pocket. But it made sense after I’d thought about it.”
    Brings back memories of driving north up Entre-Deux-Mers & encountering a very large French military chopper travelling south on the same road. Nearly took the roof off.
    Come to think of it, also of standing at the Citadelle de Blaye & looking down on a couple of their jets headed up the Gironde. Makes one wonder if French fliers don’t actually have their own maps.

  15. I’m guessing it’s been done because there’s a rule requiring it.

    Generally speaking I don’t find it helpful to assume that rules are backed up by solid reasoning.

  16. Interesting that they are putting it down to too much cash

    That was my take: if an organisation gets too rich, the parasitical classes sniff it out and take over.

  17. “On my first trip in an Army Air Corps helicopter I was surprised to find the pilot had an AA route map in his map pocket. But it made sense after I’d thought about it.”

    A pal of mine found the same thing flying from Scotland to Exter in a military helicopter: M6 then M5.

  18. If the warning markers are only above roads, perhaps: a warning to workers using ‘cherry pickers’ trimming branches of trees next to road; workers repairing phone lines or low voltage power cables next to roads; drivers of vehicles with unusually high loads; anyone who might operate a crane for some reason on or near the road.

  19. There is some great footage of a Kazakh helicopter pilot who got lost and so landed on a road to ask for directions. I have always thought that this would be pretty much the definition of a brown trouser job – how would you feel if a Soviet-era helicopter loomed out of the mist and landed in front of your car?

    http://www.bbc.com/news/av/world-asia-38996750/helicopter-pilot-lands-to-ask-for-directions-in-kazakhstan

    https://www.youtube.com/watch?v=JlLfxVhCUcw

    I love that the pilot was on a visual orientation exercise. But in all fairness what else should he do? If you have a helicopter it seems a reasonable option to me.

  20. There’s a full 10 mins of the second Johnny English film using exactly this gag.

  21. I know that around here they are used for birds – specifically to make the lines more conspicuous. AIUI they are only used on routes commonly frequented by large birds (eg swans) that have the wingspan to bridge the wires and … zaaaap.
    It will vary from area to area, on the problem being addressed, and also with the line voltage.
    On a new bypass near home, there are several sets of wires crossing the road which are nothing to do with any services – they are squirrel crossings. They have marker balls on some of the wires.

  22. It is quite common for General Aviation to follow line features, such as roads & railways: keep the feature on your left so you pass to the right of the clown doing the same coming the other way. So identifying such hazards for low flying aircraft, helis doing pipeline inspections, police choppers etc makes low-cost sense.
    Following roads is hard, as without the road-atlas colours, they all look the same. Motorways just about apparent. Interchanges are the best!
    I’ve flown many many miles IFR (I’m Following Railways), they are much rarer than roads, with fewer turnings, so you have a better chance of not missing by much.
    And yes, very greatful for the balls on low cables! Saved mine.

  23. @Chertiozhnik, May 13, 2018 at 10:11 pm

    Flying below 500′ in the UK is generally forbidden…

    Except RAF.

    In summer 1987 I had a brown pants moment on MC when two very low flying Tornados following the A1 approached me from behind. Noise was very loud, but nothing in mirrors. I rode onto grass verge as I thought a lorry was going to obliterate me.

  24. So, after one day and 29 comments, nobody actually knows.
    All I can add is that Lt. Gransden Airfield (EGMJ) has them on the power lines that cross the field, so I guess they are for viability (it’s not good to hit wires on short finals).

  25. I was always under the impression they were mostly to stabilize long cable/wire combinations and keep them from whipping or oscillating in winds.

  26. “Except RAF.

    In summer 1987 I had a brown pants moment on MC when two very low flying Tornados following the A1 approached me from behind. Noise was very loud, but nothing in mirrors. I rode onto grass verge as I thought a lorry was going to obliterate me.”

    Well, the RAF Chinook choppers out of Odiham appear to use the M3 as their route guide on their daily sorties to and from London

  27. @Will,

    What confused me, other than nothing in mirrors, was my speed was ~70mph and I knew lorries didn’t go that fast – yet the “noise” was rapidly approaching.

    My initial reaction was accelerate away from threat, gave up on that at ~130mph. GPz900R

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