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Electric and magnetic fields and health

index/glossary | EMFs At A Glance | EMF The Facts (pdf)
  • What are EMFs
    • Terminology – an introduction
    • Electric fields
    • Magnetic fields
    • Units for measuring EMFs
    • Measuring and calculating EMFs
      • “EMF Commercial”
    • Adding fields together
    • Radiofrequencies
    • Screening EMFs
  • Sources
    • Overhead power lines
      • Fields from specific power lines
        • 400 kV
        • 400 kV – specific cases
        • 275 kV
        • 132 kV
        • 66 kV
        • 33 kV
        • 11 kV
        • 400 V/230 V
        • Replacing a 132 kV line with a 400 kV line
      • Summaries of fields from all power lines
      • Factors affecting the field from a power line
        • Voltage
        • Current
        • Clearance
        • Height above ground
        • Conductor bundle
        • Phasing
        • Balance between circuits
        • Balance within circuit
        • Ground resistivity
        • Two parallel lines
      • Calculating and measuring fields from power lines
        • Geometries of power lines
        • Raw data
        • On-line calculator
      • Fields from power lines – more detail on the physics
        • Field lines from a power line
        • The direction of the field from a power line
        • Power law variations in the field from a power line
      • Statistics of power line fields
    • Underground power cables
      • Different types of underground cable
      • Fields from cables in tunnels
      • Gas Insulated Lines (GIL)
      • Underground cables with multiple conductors
      • Effect of height on fields from underground cables
      • Screening fields from underground cables
    • Low-voltage distribution
      • UK distribution wiring
      • USA distribution wiring
    • House wiring
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      • National Grid substations
        • Static Var Compensators
      • Sealing-end compounds
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        • Indoor substations
    • Transport
      • EMFs from electric trains (UK)
      • EMFs from cars
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      • Smart meters
      • Traditional meters
    • Occupational exposures
      • Live-line work
      • Static Var Compensators
      • Occupational exposures on pylons
    • Field levels and exposures
      • Personal exposure
      • Other factors that vary with magnetic fields
      • Fields greater than 0.2 or 0.4 µT
    • Screening EMFs
      • Screening fields from underground cables
      • EMF Reduction Devices
  • Known effects
    • Induced currents and fields
    • Microshocks
      • Control of microshocks in the UK
      • Microshocks from bicycles
      • Bees and microshocks
    • EMFs and medical devices
      • Standards relating to pacemakers and other AIMDs
    • Effects of EMFs on equipment
  • Research
    • Types of research
    • Epidemiology
    • Animal and laboratory experiments
    • Mechanisms
    • Specific studies
      • UKCCS
      • CCRG
      • French Geocap study
      • CEGB cohort
      • Imperial College study
  • Current evidence on health
    • Childhood leukaemia
      • Survival from childhood leukaemia
      • Childhood leukaemia and Downs
      • Childhood leukaemia and night-time exposure
      • The “contact current” hypothesis
    • Other health effects
    • Scientific review bodies
      • WHO
      • IARC
    • Electric fields and ions
    • Comparing EMFs to other issues
  • Exposure limits for people
    • Limits in the UK
    • Limits in the EU
    • Limits in the USA
    • Limits in the rest of the world
    • Limits from specific organisations
      • ICNIRP 1998
      • ICNIRP 2010
      • NRPB 1993
      • NRPB 2004
      • EU 2004
      • EU 2013
  • Policy
    • UK policy
      • Power lines and property – UK
    • Compliance with exposure limits
    • European EMF policy
    • Precaution
    • SAGE
      • SAGE First Interim Assessment
        • Government response to SAGE First Interim Assessment
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        • SAGE Second Interim Assessment – the full list of recommendations
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    • Static fields – the expert view
You are here: Home / Known effects / Microshocks / Microshocks from bicycles

Microshocks from bicycles

Microshocks are the phenomenon when a person gets charged in an electric field.  When they touch a conducting object they discharge, and although the amount of charge involved is small, because that is concentrated on the small area of the skin where the contact is first made, it produces a sensation very much like the discharge you can sometimes get after walking across a carpet.  See more on microshocks in general.

Cyclist under overhead lineOne specific way this can happen is by riding a bicycle underneath a high-voltage power line.  If you are in electrical contact with a metal part of the bicycle all the times, then no charge can build up between you and the bicycle, and you should not experience any microshocks.  But if you are electrically isolated from the bicycle - e.g. you are holding rubber handlebar grips, or are wearing insulating gloves - then a charge can build up.  This can then discharge as a microshock.  The commonest place for this to happen is either on the fingers if they brush against the brake lever, or in the inside of the upper thigh, as it comes close to the top of the seat pillar just below the saddle or to the saddle rails once each pedal revolution.

These microshocks do not cause any harm to the body or have any lasting effects that we know of.  But in the highest fields - that is, under spans of 400 kV power lines with the lowest clearance - they can be mildly painful, and they are certainly disconcerting because they are usually unexpected. (more on electric field levels under high-voltage power lines and on the sizes of the voltages and charges involved in microshocks). Because microshocks are unexpected, the cyclist may suffer a startle reaction, which on rare occasions could present a safety issue. 

They are, however, completely avoidable, by the very simple measure of keeping a finger touching the brake lever (or the bare handlebar inboard of the handlebar grips, or a metal bar end, or any other metal part of the bicycle) for as long as you are under the power line.  You don't need to grip it tightly, as long as there is a firm contact (if you only lightly brush your finger against the brake lever, you run the risk of getting microshocks at that point, which is the very thing you are trying to avoid).

After dark, the microshocks may be visible as small flashes, less than a millimetre long.  Again, this can be disconcerting if you are not expecting it, but there is nothing untoward about it; the energy in the flashes is very low, and it does not indicate any fault with the power line.

If you experience problems on a bicycle under a power line that seem worse than the description here, please let us know as we would like to investigate. Additionally, we'd like to disseminate this information as widely as possible. If you are a member of a cycle forum or group, please share this information with your members. 

Should I expect a microshock every time I cycle under a power line?

No!

We've already talked about the particular conditions that have to exist between you and the bicycle.

  • If you are completely insulated from the bicycle - holding rubber or cork grips - and there is nowhere for contact to be made - your saddle does not have any metal parts in the right place underneath, or you are wearing insulating shorts - then you will not get any microshocks (a charge builds up, but there is nowhere for it to discharge).
  • Conversely, if you are in good electrical contact with the bicycle - holding a metal brake lever or touching metal bars - you will not get microshocks (no charge builds up in the first place).

 

But in addition:

  • The power line needs to be high-voltage - usually 400 kV, or possibly 275 kV. More on telling the different types of pylon apart.
  • It needs to be fairly low clearance, because that increases the electric field - more on the effect of clearance.
  • And it probably needs to be warm dry weather - in humid conditions, the charges are more likely to leak away.

So, the vast majority of times, you will cycle under power lines without experiencing any microshocks at all.

See also

  • What are microshocks?
  • Are there limits related to microshocks?

Latest news

  • New publication on cancer incidence from the UK electricity industry Cohort Study August 27, 2019
  • How has the reported risk for childhood leukaemia changed over time? February 11, 2019
  • Media stories about microshocks in children’s playground September 10, 2018
  • New studies on leukaemia and distance from power lines June 1, 2018
older news

Contact Us

To contact the electricity industry’s EMF Unit Public Information Line (UK only):
telephone 0845 7023270 or email [email protected].

See Contact us for more contact details including our privacy policy.

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Navigation
  • What are EMFs
    • Terminology – an introduction
    • Electric fields
    • Magnetic fields
    • Units for measuring EMFs
    • Measuring and calculating EMFs
      • “EMF Commercial”
    • Adding fields together
    • Radiofrequencies
    • Screening EMFs
  • Sources
    • Overhead power lines
      • Fields from specific power lines
        • 400 kV
        • 400 kV – specific cases
        • 275 kV
        • 132 kV
        • 66 kV
        • 33 kV
        • 11 kV
        • 400 V/230 V
        • Replacing a 132 kV line with a 400 kV line
      • Summaries of fields from all power lines
      • Factors affecting the field from a power line
        • Voltage
        • Current
        • Clearance
        • Height above ground
        • Conductor bundle
        • Phasing
        • Balance between circuits
        • Balance within circuit
        • Ground resistivity
        • Two parallel lines
      • Calculating and measuring fields from power lines
        • Geometries of power lines
        • Raw data
        • On-line calculator
      • Fields from power lines – more detail on the physics
        • Field lines from a power line
        • The direction of the field from a power line
        • Power law variations in the field from a power line
      • Statistics of power line fields
    • Underground power cables
      • Different types of underground cable
      • Fields from cables in tunnels
      • Gas Insulated Lines (GIL)
      • Underground cables with multiple conductors
      • Effect of height on fields from underground cables
      • Screening fields from underground cables
    • Low-voltage distribution
      • UK distribution wiring
      • USA distribution wiring
    • House wiring
    • Substations
      • National Grid substations
        • Static Var Compensators
      • Sealing-end compounds
      • Distribution substations
      • Final distribution substations
        • Indoor substations
    • Transport
      • EMFs from electric trains (UK)
      • EMFs from cars
    • Appliances
    • Electricity meters
      • Smart meters
      • Traditional meters
    • Occupational exposures
      • Live-line work
      • Static Var Compensators
      • Occupational exposures on pylons
    • Field levels and exposures
      • Personal exposure
      • Other factors that vary with magnetic fields
      • Fields greater than 0.2 or 0.4 µT
    • Screening EMFs
      • Screening fields from underground cables
      • EMF Reduction Devices
  • Known effects
    • Induced currents and fields
    • Microshocks
      • Control of microshocks in the UK
      • Microshocks from bicycles
      • Bees and microshocks
    • EMFs and medical devices
      • Standards relating to pacemakers and other AIMDs
    • Effects of EMFs on equipment
  • Research
    • Types of research
    • Epidemiology
    • Animal and laboratory experiments
    • Mechanisms
    • Specific studies
      • UKCCS
      • CCRG
      • French Geocap study
      • CEGB cohort
      • Imperial College study
  • Current evidence on health
    • Childhood leukaemia
      • Survival from childhood leukaemia
      • Childhood leukaemia and Downs
      • Childhood leukaemia and night-time exposure
      • The “contact current” hypothesis
    • Other health effects
    • Scientific review bodies
      • WHO
      • IARC
    • Electric fields and ions
    • Comparing EMFs to other issues
  • Exposure limits for people
    • Limits in the UK
    • Limits in the EU
    • Limits in the USA
    • Limits in the rest of the world
    • Limits from specific organisations
      • ICNIRP 1998
      • ICNIRP 2010
      • NRPB 1993
      • NRPB 2004
      • EU 2004
      • EU 2013
  • Policy
    • UK policy
      • Power lines and property – UK
    • Compliance with exposure limits
    • European EMF policy
    • Precaution
    • SAGE
      • SAGE First Interim Assessment
        • Government response to SAGE First Interim Assessment
      • SAGE Second Interim Assessment
        • Government response to SAGE Second Interim Assessment
        • SAGE Second Interim Assessment – the full list of recommendations
  • Finding out more
    • EMF measurement and commercial services
    • Links
    • Literature
    • Contact us
  • Static fields
    • Static fields – the expert view