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Electric and magnetic fields and health

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  • What are EMFs
    • Terminology – an introduction
    • Electric fields
    • Magnetic fields
    • Units for measuring EMFs
    • Measuring and calculating EMFs
      • EMF instruments and other commercial services
    • 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
      • Fields in different countries
      • How fields vary with time
    • Reducing your exposure
  • Known effects
    • Induced currents and fields
      • Numerical calculations of induced currents
      • Details of numerical calculations of induced currents and fields in the body
    • Effects of EMFs on equipment
    • EMFs and medical devices
      • Types of medical devices
      • Real-life experience of interference with Implanted Heart Devices
      • Laboratory Tests of Implanted Medical Devices
      • Consequences if interference does occur with an implanted heart device
      • Manufacturers of Implanted Heart Devices
      • Standards relating to pacemakers and other AIMDs
      • Interference with hearing aids and cochlear implants
    • Microshocks
      • Control of microshocks in the UK
      • Microshocks from bicycles
    • EMFs, agriculture and the environment
      • Bees and microshocks
      • Behaviour of large mammals in magnetic fields and near power lines
  • Evidence on health
    • Childhood leukaemia
      • Pooled analyses of childhood leukaemia and magnetic fields
      • Number of children affected
      • Childhood leukaemia and night-time exposure
      • Survival from childhood leukaemia
      • Childhood leukaemia and Downs
      • The “contact current” hypothesis
      • The causes of childhood leukaemia
    • Other health effects
      • Other childhood cancer
      • Breast cancer
      • Other adult cancers
      • Cardiovascular disorders
      • Neurodegenerative disorders
      • Epilepsy
      • Reproductive outcomes and disorders
      • Suicide and depression
      • Sleep disturbance
      • Asthma
      • Hypersensitivity
      • Effects of parental exposure to EMFs
    • Scientific review bodies
      • WHO
      • IARC
      • ICNIRP
      • SCENIHR
      • PHE (formerly HPA, formerly NRPB)
      • IET
      • NAS
      • NIEHS
      • California
      • Bioinitiative
    • Electric fields and ions
      • Electric fields and ions – a commentary on the suggestions
      • Electric fields and ions – NRPB comments
      • Skin cancer
      • Air pollution and childhood cancer
      • How many corona ions do power lines produce?
    • Comparing EMFs to other issues
      • EMFs compared to other issues: smoking
      • EMFs compared to other issues: passive smoking
      • EMFs compared to other issues: coffee
      • EMFs compared to other issues: shift work
      • EMFs compared to other issues: cholera
      • EMFs compared to other issues: BSE and variant CJD
      • Comparative risks
  • Research
    • Types of research
      • Research ethics
    • Epidemiology
      • Causation – what can epidemiology show and what can’t it?
      • Confounding
      • Clusters
    • Animal and laboratory experiments
      • Behaviour of large mammals in magnetic fields and near power lines
    • Mechanisms
      • Energy issues in mechanisms
      • Free radicals
      • Melatonin
      • Cryptochromes
      • Total field and AC field
    • Specific studies
      • UKCCS
      • CCRG
        • CCRG distance study
        • CCRG magnetic fields study
        • CCRG “corona ions” paper
        • CCRG follow-on paper
        • CCRG Underground cables paper
        • CCRG “wrap up” paper
        • CCRG Note on distance
        • Responses to the various CCRG papers
      • French Geocap study
      • California power lines study
      • Imperial College study
      • CEGB cohort
      • Transexpo
    • Ongoing research
      • UK electricity industry research
    • Non peer-reviewed science
    • Abstracts of papers
      • Childhood leukaemia abstracts
      • The CCRG (or “Draper”) study abstracts
      • The UKCCS abstracts
      • The CEGB cohort abstracts
      • Alzheimer’s disease abstracts
      • Breast cancer abstracts
      • Suicide and depression abstracts
      • Animal toxicology experiments abstracts
      • Numerical calculations of induced current – abstracts
      • Abstracts related to the Contact Current Hypothesis
      • Abstracts relating to research on fruit flies
      • Abstracts relating to animal behaviour: orientation in magnetic fields and sensing of power lines
  • Exposure limits
    • Limits in the UK
    • Limits in the USA
    • Limits in the EU
    • Limits in the rest of the world
    • Limits from specific organisations
      • ACGIH
      • NRPB 1993
      • ICNIRP 1998
      • EU 1999
      • ICES 2002
      • NRPB 2004
      • EU 2004
      • SBM 2008
      • ICNIRP 2010
      • EU 2013
      • The Control of Electromagnetic Fields at Work Regulations 2016
      • International Guidelines on Non-Ionising Radiation 2018
      • Comparison of exposure limits across frequencies
    • Indirect effects in exposure limits
    • Compliance with exposure limits
  • Policy
    • UK policy
      • Consent for power lines
      • Cross-Party Inquiry
      • Early Day Motions
      • Parliamentary Questions and Answers
      • UK Government and Parliament
    • European EMF policy
    • Power lines and property – UK
      • Corridors round power lines
    • Power lines and property – USA
    • Precaution
    • SAGE
      • SAGE First Interim Assessment
      • Government response to SAGE First Interim Assessment
      • SAGE Second Interim Assessment
      • Government response to SAGE Second Interim Assessment
    • Public Opinion on EMFs
      • Opinion polls conducted by Ipsos MORI on power lines and EMFs
    • Communications on EMFs
    • Litigation on EMFs
  • Finding out more
    • Links
    • Literature
    • Contacts
    • Finding out about other issues
      • Finding out more: Wayleaves and easements
      • Finding out more: Safety clearance distances
      • “Danger of death” notices
      • Finding out more: Audible noise
      • Finding out more: Power lines and satellite navigation
      • Finding out more: Radio and TV interference
  • Static fields
    • Sources of static fields
      • Fields from underground DC cables
      • Effects of static fields on compasses
    • Effects of static fields
    • Static fields – the expert view
      • Types of medical devices
      • WHO – static fields
      • IARC – static fields
      • ICNIRP – static fields
      • PHE – static fields
    • Static field limits
You are here: Home / Sources / Overhead power lines / Fields from specific power lines / 11 kV

11 kV

thumbnail of distribution wood pole

11 kV lines are either carried on small lattice steel pylons or on wood poles.  There are many different variants of lines design but they all produce roughly similar fields.

All 11 kV lines are inherently compliant with the public exposure limits - see more details

Magnetic field

The maximum field shown here is produced by a lattice pylon design when the ground clearance is the minimum allowed – 5.5 m – and the loads are the highest allowed – not usually above 500 A in each circuit but there may be exceptions.  The field also depends on the phasing. 11 kV lines usually have Untransposed (U) phasing.

graph of maximum field 11 kV 

Typical fields are lower than the maximum field because the clearance is usually higher and the loads are usually lower.  The two curves shown here are for typical loads, the normal U phasing, and two different line designs: a lattice steel pylon (the higher field), and a wood-pole design (the lower field).

graph of typical field from 11 kV 

 

This table gives some actual field values for the same conditions.

 

magnetic field in µT at distance from centreline

maximum under line

10 m

25 m

50 m

100 m

11 kV

larger lines on steel pylons

SL11

single conductors

maximum

clearance 5.5 m
phasing U
load 0.5/0.5 kA

9.456

7.664

1.490

0.364

0.090

typical

clearance 8 m
phasing U
load 0.1 kA

1.004

0.942

0.274

0.071

0.018

smaller lines on wood poles

wood pole

horizontal array

+-1.15 m

maximum

clearance 5.5 m
single circuit
load 0.2 kA

3.744

0.668

0.124

0.032

0.008

typical

clearance 8 m
single circuit
load 0.05 kA

0.399

0.134

0.030

0.008

0.002

Note:

1. All fields calculated at 1 m above ground level.

2. All fields are given to the same resolution for simplicity of presentation (1 nT = 0.001 µT) but are not accurate to better than a few percent.

3. Calculations ignore zero-sequence current.  This means values at larger distances are probably underestimates, but this is unlikely to amount to more than a few percent and less closer to the line.

4. The “maximum field under the line” is the largest field, which is not necessarily on the route centreline; it is often under one of the conductor bundles.

5. Sometimes, an 11 kV circuit could be carried on a line designed for a higher voltage.  Then the magnetic fields could be larger than shown here.

6. The dip in field on the centreline between the two circuits happens when the two circuits are carrying the same load, and is less pronounced if the loads are different.

Electric field

The maximum field shown here is produced by a lattice pylon design when the ground clearance is the minimum allowed – 5.5 m. The field also depends on the phasing. 11 kV lines usually have Untransposed (U) phasing.

graph of maximum field from 11 kV 

Typical fields are lower than the maximum field because the clearance is usually higher.  The two curves shown here are for the normal U phasing and two different line designs: a lattice steel pylon (the higher field), and a wood-pole design (the lower field).

graph of typical field from 11 kV 


 This table gives some actual field values for the same conditions.

     

electric field in V m-1 at distance from centreline

maximum under line

10 m

25 m

50 m

100 m

11 kV

larger lines on steel pylons

SL11

single conductors

maximum

clearance 5.5 m
phasing U

215

109

13

5

1

typical

clearance 8 m
phasing U

122

82

8

4

1

smaller lines on wood poles

wood pole

horizontal array

+-1.15 m

maximum

clearance 5.5 m
single circuit

108

32

3

0

0

typical

clearance 8 m
single circuit

50

29

4

1

0

Note:

1. All fields calculated at 1 m above ground level.

2. All electric fields are calculated for the nominal voltage.  In practice, voltages (and hence fields) may rise by a few percent.

3. All electric fields calculated here are unperturbed values.

4. All fields are given to the same resolution for simplicity of presentation (1 V/m) but are not accurate to better than a few percent.

5. Calculations ignore zero-sequence voltages.  This means values at larger distances are probably underestimates, but this is unlikely to amount to more than a few percent and less closer to the line.

6. The “maximum field under the line” is the largest field, which is not necessarily on the route centreline; it is often under one of the conductor bundles.

7. Sometimes, an 11 kV circuit could be carried on a line designed for a higher voltage.  Then the electric fields could be larger than shown here.

Underground cables

11 kV underground cables are usually a single cable: the three cores are twisted round each other in a single outer sheath. Because the cores are so close together and twisted, the fields they produce directly are very small.  Instead, the field comes from any net current in the sheath.  This is very variable and cannot be predicted accurately.

The following graph shows typical fields from the net current in a 11 kV cable.

graph of typical field from 11 kV underground cable 

Occasionally an 11 kV cable may have separate cores.  Then the field would be more like a 132 kV cable with separate cores.

Underground cables do not produce any external electric fields.

This table gives some actual field values for the same conditions.

    

magnetic field in µT at distance from centreline

0 m

5 m

10 m

20 m

11 kV

single cable

0.5 m depth

typical

0.75

0.22

0.11

0.06

Notes

1. All fields calculated at 1 m above ground level

2. All fields are given to the same resolution for simplicity of presentation (0.01 µT = 10 nT) but are not accurate to better than a few percent.

3. These calculations are for a single, isolated cable.  This is rare in practice.  Other nearby cables would modify the field.

Other voltages:

  • 400 kV
  • 400kV special cases
  • 275 kV
  • 132 kV
  • 66 kV
  • 33 kV
  • 11 kV
  • 400 V/230 V

Latest news

  • 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
  • UK media interest in the causes of childhood leukaemia May 22, 2018
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Navigation
  • What are EMFs
    • Terminology – an introduction
    • Electric fields
    • Magnetic fields
    • Units for measuring EMFs
    • Measuring and calculating EMFs
      • EMF instruments and other commercial services
    • 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
      • Fields in different countries
      • How fields vary with time
    • Reducing your exposure
  • Known effects
    • Induced currents and fields
      • Numerical calculations of induced currents
      • Details of numerical calculations of induced currents and fields in the body
    • Effects of EMFs on equipment
    • EMFs and medical devices
      • Types of medical devices
      • Real-life experience of interference with Implanted Heart Devices
      • Laboratory Tests of Implanted Medical Devices
      • Consequences if interference does occur with an implanted heart device
      • Manufacturers of Implanted Heart Devices
      • Standards relating to pacemakers and other AIMDs
      • Interference with hearing aids and cochlear implants
    • Microshocks
      • Control of microshocks in the UK
      • Microshocks from bicycles
    • EMFs, agriculture and the environment
      • Bees and microshocks
      • Behaviour of large mammals in magnetic fields and near power lines
  • Evidence on health
    • Childhood leukaemia
      • Pooled analyses of childhood leukaemia and magnetic fields
      • Number of children affected
      • Childhood leukaemia and night-time exposure
      • Survival from childhood leukaemia
      • Childhood leukaemia and Downs
      • The “contact current” hypothesis
      • The causes of childhood leukaemia
    • Other health effects
      • Other childhood cancer
      • Breast cancer
      • Other adult cancers
      • Cardiovascular disorders
      • Neurodegenerative disorders
      • Epilepsy
      • Reproductive outcomes and disorders
      • Suicide and depression
      • Sleep disturbance
      • Asthma
      • Hypersensitivity
      • Effects of parental exposure to EMFs
    • Scientific review bodies
      • WHO
      • IARC
      • ICNIRP
      • SCENIHR
      • PHE (formerly HPA, formerly NRPB)
      • IET
      • NAS
      • NIEHS
      • California
      • Bioinitiative
    • Electric fields and ions
      • Electric fields and ions – a commentary on the suggestions
      • Electric fields and ions – NRPB comments
      • Skin cancer
      • Air pollution and childhood cancer
      • How many corona ions do power lines produce?
    • Comparing EMFs to other issues
      • EMFs compared to other issues: smoking
      • EMFs compared to other issues: passive smoking
      • EMFs compared to other issues: coffee
      • EMFs compared to other issues: shift work
      • EMFs compared to other issues: cholera
      • EMFs compared to other issues: BSE and variant CJD
      • Comparative risks
  • Research
    • Types of research
      • Research ethics
    • Epidemiology
      • Causation – what can epidemiology show and what can’t it?
      • Confounding
      • Clusters
    • Animal and laboratory experiments
      • Behaviour of large mammals in magnetic fields and near power lines
    • Mechanisms
      • Energy issues in mechanisms
      • Free radicals
      • Melatonin
      • Cryptochromes
      • Total field and AC field
    • Specific studies
      • UKCCS
      • CCRG
        • CCRG distance study
        • CCRG magnetic fields study
        • CCRG “corona ions” paper
        • CCRG follow-on paper
        • CCRG Underground cables paper
        • CCRG “wrap up” paper
        • CCRG Note on distance
        • Responses to the various CCRG papers
      • French Geocap study
      • California power lines study
      • Imperial College study
      • CEGB cohort
      • Transexpo
    • Ongoing research
      • UK electricity industry research
    • Non peer-reviewed science
    • Abstracts of papers
      • Childhood leukaemia abstracts
      • The CCRG (or “Draper”) study abstracts
      • The UKCCS abstracts
      • The CEGB cohort abstracts
      • Alzheimer’s disease abstracts
      • Breast cancer abstracts
      • Suicide and depression abstracts
      • Animal toxicology experiments abstracts
      • Numerical calculations of induced current – abstracts
      • Abstracts related to the Contact Current Hypothesis
      • Abstracts relating to research on fruit flies
      • Abstracts relating to animal behaviour: orientation in magnetic fields and sensing of power lines
  • Exposure limits
    • Limits in the UK
    • Limits in the USA
    • Limits in the EU
    • Limits in the rest of the world
    • Limits from specific organisations
      • ACGIH
      • NRPB 1993
      • ICNIRP 1998
      • EU 1999
      • ICES 2002
      • NRPB 2004
      • EU 2004
      • SBM 2008
      • ICNIRP 2010
      • EU 2013
      • The Control of Electromagnetic Fields at Work Regulations 2016
      • International Guidelines on Non-Ionising Radiation 2018
      • Comparison of exposure limits across frequencies
    • Indirect effects in exposure limits
    • Compliance with exposure limits
  • Policy
    • UK policy
      • Consent for power lines
      • Cross-Party Inquiry
      • Early Day Motions
      • Parliamentary Questions and Answers
      • UK Government and Parliament
    • European EMF policy
    • Power lines and property – UK
      • Corridors round power lines
    • Power lines and property – USA
    • Precaution
    • SAGE
      • SAGE First Interim Assessment
      • Government response to SAGE First Interim Assessment
      • SAGE Second Interim Assessment
      • Government response to SAGE Second Interim Assessment
    • Public Opinion on EMFs
      • Opinion polls conducted by Ipsos MORI on power lines and EMFs
    • Communications on EMFs
    • Litigation on EMFs
  • Finding out more
    • Links
    • Literature
    • Contacts
    • Finding out about other issues
      • Finding out more: Wayleaves and easements
      • Finding out more: Safety clearance distances
      • “Danger of death” notices
      • Finding out more: Audible noise
      • Finding out more: Power lines and satellite navigation
      • Finding out more: Radio and TV interference
  • Static fields
    • Sources of static fields
      • Fields from underground DC cables
      • Effects of static fields on compasses
    • Effects of static fields
    • Static fields – the expert view
      • Types of medical devices
      • WHO – static fields
      • IARC – static fields
      • ICNIRP – static fields
      • PHE – static fields
    • Static field limits