Electric shock frame!
nasha48
Posts: 231
Hi peeps. For at least a year now I have been experiencing sharp electric shocks whilst riding along on my Boardman FS. Quite regularly, if my inner knee contacts the top tube I get zinged. Just wondered if this is a common problem for anyone else and whether there is anything obvious causing it? For info, I've just replaced the BB (which I thought may be the cause) and it still happens. All that's left in my opinion is the wheel hubs (stock Ritchey front, Hope Pro2 Evo rear).
0
Comments
-
Nasha48 wrote:Hi peeps. For at least a year now I have been experiencing sharp electric shocks whilst riding along on my Boardman FS. Quite regularly, if my inner knee contacts the top tube I get zinged. Just wondered if this is a common problem for anyone else and whether there is anything obvious causing it? For info, I've just replaced the BB (which I thought may be the cause) and it still happens. All that's left in my opinion is the wheel hubs (stock Ritchey front, Hope Pro2 Evo rear).
Static electricity tends to build up when two non-conductive materials rub against each other. The shock you experience is occurring when the static that has built-up is then being discharged instantaneously by your contact with the metal of the frame.
The static build-up could be a result of the rubbing of your shorts' material against that of the saddle, or a tyre just skimming a plastic mudguard. It's likely that it's down to a particular combination of materials, so check these sort of plastic-on-plastic contact areas, and change one of the materials where you can to see if you can identify the problem pairing.0 -
Especially bad if you ride on nylon carpets.I don't do smileys.
There is no secret ingredient - Kung Fu Panda
London Calling on Facebook
Parktools0 -
Is that from experience?0
-
Nope, worst I've had is carpet burns on the knees.I don't do smileys.
There is no secret ingredient - Kung Fu Panda
London Calling on Facebook
Parktools0 -
cooldad wrote:Nope, worst I've had is carpet burns on the knees.
You should tell him to wheel you forward a little slower.All the gear, no idea and loving the smell of jealousy in the morning.
Kona Process 134 viewtopic.php?f=10017&t=129946070 -
Cheers jimothy, makes sense! Next ride will be naked then to rule out the clothing rubbing...
Rest of you, cheers for the humour!0 -
WOW first time I have heard of this, but you are producing a positive charge that your frame seems love until you touch her and then she will pass all of her negative energy to you (or create a potential difference) this is a love hate relationship at it's best, just don't introduce her to a 4kv flash test haha.0
-
0
-
Out of curiosity when your knee touches the top tube, is this exposed metal? And does this happen while riding or whilst you are stopped and have one foot on the ground? The tyres should be quite insulating into the high megaohm range. So I can't perceive how you would get a shock until you come in to contact with ground and touching exposed metalwork at the same time.0
-
If I had some fresh batteries I would quite happily "megger" my bike with 2kv to earth with me sat on it and post the results.
Your points of contact should all be insulated, I can only assume you are touching bare metal and ground at the same time to create a potential difference.0 -
Does it have the original white saddle and grips? (latest ones use a black saddle).
Black plastic is 'coloured' using carbon black, that is enough to make the plastic mildly conducting and prevent a build of static.
I have had an occasional static shock when using a white Carrera saddle (identical to the older Boardman white except for the logo) on a Giant bike with white grips, not on a Giant with black grips (hire bikes, but the Giant saddle is an instrument of torture and not something designed to actually be sat on).
CD is clearly not a gentleman as they take their weight on their elbows and suffer there as well.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
Thanks for all the opinions. Black saddle, black grips Rookie. Re whether it's when I stop and put my foot on the ground - I honestly don't think it's the case and it generally happens as I'm cruising along. In fact, I often deliberately move my knee in (or sometimes touch with my hand) to touch the frame so I can discharge the current before it gets too big!! Surely it must be a clothing rub issue then as suggested. Cyd - appreciate the thought but it's defo not injury or nerve related. Clearly though, despite hitting the 40 mark soon, I still have electricity coursing through the veins...0
-
Thanks for all the opinions. Black saddle, black grips Rookie. Re whether it's when I stop and put my foot on the ground - I honestly don't think it's the case and it generally happens as I'm cruising along. In fact, I often deliberately move my knee in (or sometimes touch with my hand) to touch the frame so I can discharge the current before it gets too big!! Surely it must be a clothing rub issue then as suggested. Cyd - appreciate the thought but it's defo not injury or nerve related. Clearly though, despite hitting the 40 mark soon, I still have electricity coursing through the veins...
Without calling you a liar, I don't see how you can get a shock whilst cruising.
Your contact points to ground are rubber tires inflated with air, I consider these to be highly insulating. All of your contact points with the bike will also be insulating. With no path to ground you won't get an electric shock, hence my comment I would quite happily "megger" with 2kv between me and a tire.
All of your contact points, saddle grips, pedals (unless you ride bare foot), tires will all be insulating materials. But and this is a big but, they can become conductive but this would involve many thousands of volts for the materials to "breakdown" or flashover.
The only conceivable way in my mind would be if you were using a steel wire tire, and it was damaged where it seats on the rim and exposing metal, and if your tire was worn down enough to exposed metal but the chances of this, I think you would have more chance being struck by lightning.
You must have a contact with ground in order to get a shock. You should have no PD unless in contact with ground. From a bare metal point on your bike to your tires will be open circuit, ie, many many hundreds of mega ohms. If I am proven to be wrong I will happily eat humble pie. Heck I even just did it as a curiosity thing with a fluke meter that cost the same as my bike with a resistance range to 500 mega ohm or 0.5 giga ohm, and as expected open circuit.0 -
But if you are quick like Flash Gordan maybe you could build up a massive potential difference to the point where insulating materials break down and start becoming conductive.
This may give you a clue to my BG and why I am saying this.
Electricity always takes the path of least resistance, so if you were cruising on rubber tires and a bed of air (these are very well insulating materials) then the charge would have no path to ground. So you can't get a shock if you are "cruising" for this to happen there would need to be anomalies creating a path of least resistance.
0 -
Well done for missing the point completely, if the rider builds up a static potential, with no conduction then they will then get a shock when they touch the bike frame, so you have just shown why it WOULD happen, and not why it would NOT. The bike doesn't have to be gaining any potential relative to 'earth' but the rider maybe due to what they are wearing.[url=http://www.bikeradar.com/forums/viewtopic.php?p=19621507#p19621507]Clockworkmark31[/url] wrote:Thanks for all the opinions. Black saddle, black grips Rookie. Re whether it's when I stop and put my foot on the ground - I honestly don't think it's the case and it generally happens as I'm cruising along. In fact, I often deliberately move my knee in (or sometimes touch with my hand) to touch the frame so I can discharge the current before it gets too big!! Surely it must be a clothing rub issue then as suggested. Cyd - appreciate the thought but it's defo not injury or nerve related. Clearly though, despite hitting the 40 mark soon, I still have electricity coursing through the veins...
Without calling you a liar, I don't see how you can get a shock whilst cruising.
Your contact points to ground are rubber tires inflated with air, I consider these to be highly insulating. All of your contact points with the bike will also be insulating. With no path to ground you won't get an electric shock, hence my comment I would quite happily "megger" with 2kv between me and a tire.
All of your contact points, saddle grips, pedals (unless you ride bare foot), tires will all be insulating materials. But and this is a big but, they can become conductive but this would involve many thousands of volts for the materials to "breakdown" or flashover.
The only conceivable way in my mind would be if you were using a steel wire tire.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
Careful now, he has a computer with squiggley lines!It matters not, win or lose, it's how you ride the bike0
-
You should definitely try riding naked to see if that makes a difference.All the gear, no idea and loving the smell of jealousy in the morning.
Kona Process 134 viewtopic.php?f=10017&t=129946070 -
0
-
'Bout time that idiot put it away now.All the gear, no idea and loving the smell of jealousy in the morning.
Kona Process 134 viewtopic.php?f=10017&t=129946070 -
I highlighted why it would not happen. Maybe I wasn't clear enough on my explanation, or left a few small details out accidentally on purpose.
So a few questions to the OP, what material are your brake levers and lever assemblies made from and what material is your handlebar, if you say plastic and carbon now I will cry. I would ask if you wear gloves but you say, that you discharge the static with your hand sometimes.
Next question, does this always happen in the same area? Last question do you do a lot of riding under 400kV lines on damp days. Last last question, what is the finish on your frame or from the component where this is happening.
I did say I would eat humble pie if I was wrong, but I did state way earlier it can't happen unless he is in contact with ground or a bare metal part on the bike. Can clothing build up static, yes. What are the chances of there being a PD whilst riding very very slim unless you are touching a bare metal part or ground.
Maybe my wording was a little wrong or misleading but I still stand by my point.
If you want more info have a look at this from Electric and magnetic fields and health http://www.emfs.info/effects/microshocks/microshocks-from-bicycles/0 -
[url=http://www.bikeradar.com/forums/viewtopic.php?p=19620719#p19620719]Clockworkmark31[/url] wrote:So I can't perceive how you would get a shock until you come in to contact with ground and touching exposed metalwork at the same time.
Yes I see my mistake in the wording too, but when reading this trying to answer and doing work related things at the same time with her nagging at you, I can tell you this very much creates a PD. Man can only do one thing at once.
I am going through a similar thing with work atm where new management have the blinkers on, and can't perceive how making a bench out of exposed metal and asking you to wear a 1MR anti static strap all tied down to earth whilst working on high power exposed circuits is a bad thing. The best response I had so far was from someone who "should" be in the know about this was, ah its ok, you have a 30mA RCD fitted, he looked quite dumbfounded when I was trying to explain it is a current detecting device and not a current limiting device.
So I will eat small humble pie, I knew what message I was wanting to project, it just didn't come across that way.0 -
[url=http://www.bikeradar.com/forums/viewtopic.php?p=19621507#p19621507]Clockworkmark31[/url] wrote:You must have a contact with ground in order to get a shock. You should have no PD unless in contact with ground. From a bare metal point on your bike to your tires will be open circuit, ie, many many hundreds of mega ohms. If I am proven to be wrong I will happily eat humble pie
Start eating your pie then, you are wrong. You don't need to have contact with the ground to get a shock. A potential difference exists between ANY 2 objects not just between one object and the ground. Why do you think all metal pipe work in a building is bonded? It's so any fault current also exists in that pipe work so there is no PD. Also touching 2 overhead cables will give you a shock because a PD exists even between 2 phases, and even at over 6 foot I wouldn't be touching them whilst still having contact with the ground.Clockworkmark31 wrote:The best response I had so far was from someone who "should" be in the know about this was, ah its ok, you have a 30mA RCD fitted, he looked quite dumbfounded when I was trying to explain it is a current detecting device and not a current limiting device.
Again not exactly right. It is a current limiting device as in it monitors the current flowing to ground by checking there is a balance between the phase and neutral, if they are unequal it shows a current flowing to ground and once this reaches 30mA it then cuts the supply off hence limiting that current.
I think you are confusing current limiting with over current which is designed to protect the wiring and in turn prevent a fire occurring.0 -
Hey chaps. Firstly clockwork - many thanks for all your interesting info, electricity is obviously your thing! Now then, I type the following with a red tinge in my cheeks.....
Went out for a ride after work last night and had a eureka moment on the matter. It seems to have been the cable housing where it protrudes slightly from the top tube and sometimes I brush it with the inside of my right thigh just above the knee. Yep - occasionally it pinches a hair or 2 between it and the top tube just as I'm on the upstroke and it's always felt like a tiny electric shock. But it's not. It's a hair being pulled sharply. When I've "discharged" it with my fingers a while ago, it must have coincided with the zap on the inside of my leg. Hence, I'm both embarrassed and pleased at identifying the problem. Sorry to those of you who have wasted your time trying to help!
Off to get a razor...0 -
Clockworkmark31 wrote:The best response I had so far was from someone who "should" be in the know about this was, ah its ok, you have a 30mA RCD fitted, he looked quite dumbfounded when I was trying to explain it is a current detecting device and not a current limiting device.
Again not exactly right. It is a current limiting device as in it monitors the current flowing to ground by checking there is a balance between the phase and neutral, if they are unequal it shows a current flowing to ground and once this reaches 30mA it then cuts the supply off hence limiting that current.
I think you are confusing current limiting with over current which is designed to protect the wiring and in turn prevent a fire occurring.
I will eat humble pie on my miswording.
Why is it not exactly right on the RCD? The RCD is a current monitor and not a limiter. You even mention it monitors. Yes I understand it is looking for an imbalance of 30mA to trip, but that is all it is doing is monitoring the difference until the threshold has been reached.
Now if I was working on a high power device (by working on I mean fault finding on faulty devices) and I was to touch something that I shouldn't and start receiving a shock, the RCD is monitoring for a 30mA difference, it is not limiting the amount of current flowing through me or the time that it takes for the RCD to trip.
Having carried out risk assessments today with the most senior power design and principle engineers within my company, why would they all say the same thing as me.0 -
Hey chaps. Firstly clockwork - many thanks for all your interesting info, electricity is obviously your thing! Now then, I type the following with a red tinge in my cheeks.....
Went out for a ride after work last night and had a eureka moment on the matter. It seems to have been the cable housing where it protrudes slightly from the top tube and sometimes I brush it with the inside of my right thigh just above the knee. Yep - occasionally it pinches a hair or 2 between it and the top tube just as I'm on the upstroke and it's always felt like a tiny electric shock. But it's not. It's a hair being pulled sharply. When I've "discharged" it with my fingers a while ago, it must have coincided with the zap on the inside of my leg. Hence, I'm both embarrassed and pleased at identifying the problem. Sorry to those of you who have wasted your time trying to help!
Off to get a razor...
Please don't shave. Keep the man hair. But glad your found out the cause.
If that felt like a shock, I would hate to see what you would do if you seen a online UPS 200KVA/160KW let go. Que a trip to the gentleman's room for a change in wardrobe.0 -
[url=http://www.bikeradar.com/forums/viewtopic.php?p=19621507#p19621507]Clockworkmark31[/url] wrote:Start eating your pie then, you are wrong. You don't need to have contact with the ground to get a shock. A potential difference exists between ANY 2 objects not just between one object and the ground. Why do you think all metal pipe work in a building is bonded? It's so any fault current also exists in that pipe work so there is no PD. Also touching 2 overhead cables will give you a shock because a PD exists even between 2 phases, and even at over 6 foot I wouldn't be touching them whilst still having contact with the ground.
Slightly confused by this. Maybe again it was due to my wording. Correct you don't need to be in contact with ground to get a shock, you can also receive a shock through iso ground. Touching 2 overhead cables will always give you a shock as depending on the combination in which you are touching them you are either introducing a L-N short or L-E short or N-E short. Now depending on the voltage or current depends on the resistivity of your body and I can tell you that your body acts like a direct short at mains voltages. So why would you touch them whilst being in contact with ground or an iso ground this would always result in a shock.0 -
Also we were talking about static that does require a source to ground or iso ground in order to discharge "receive a shock", so again I talked about coming in to contact with bare metal on the frame or ground itself.0
-
If I was to ask what is the difference between a 30mA RCD and a 5mA RCD what would your response be?
This I am interested in hearing. would you still believe the 5mA RCD to a 30mA RCD is a current limiting device.
They are not different, they just have different thresholds, they don't limit the current flowing through someone, they just have a different threshold. By the time the threshold is realized you could still have a few amps flowing through a person.
So how is an RCD a current limiting device? It is not. It is only a current monitor. If you believe it is a current limiter I suggest you study electronics instead of electrical installation.0 -
You need to think about it, an RCD does limit the current, you call it a monitor, which it does, but by the fact it trips it limits the current flow. Run and RCD test and look at how much current it allows to flow.
Anyway probably best not to be spamming someone's thread with a load of babble about RCDs etc.0 -
You need to think about it, an RCD does limit the current, you call it a monitor, which it does, but by the fact it trips it limits the current flow. Run and RCD test and look at how much current it allows to flow.
Anyway probably best not to be spamming someone's thread with a load of babble about RCDs etc.
I agree its best too as I don't think we will agree on this one. I have been on my period for the past few days.
But one last try to make you understand, or to give you the correct knowledge. If I was doing some electrical installation work and I cut through a live wire thinking it was dead. What happens, the RCD trips and I have to go and buy some new CK side cutters due to the nice hole in them.
If I did the same thing again using some none VDE side cutters, ie all bare metal, what would happen. The RCD would trip the side cutters would still have the same hole in them, I would have burn marks from gripping them and receive a nice belt/shock.
Now the RCD in both instances did what it was supposed to do, it tripped once it detected a difference of 30mA for example.
So do you think 30ma could cause that damage to some sidecutters or give you burn marks or a nice shock, no more than 30mA would cause all of the above damage, for however many micro, Milli or pico seconds it takes for the RCD to detect the difference, you are at the mercy of the mains. This is why the RCD is a monitor and not a limiter.
Also an RCD test is carried out in "perfect" conditions not with a mass or resistance in the way of the flow.0
