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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
    • 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
You are here: Home / Policy / Power lines and property – UK / Survey reports reporting the presence of electrical equipment

Survey reports reporting the presence of electrical equipment

In the UK, when you are buying or selling a property, you may either commission yourself, or receive as part of your survey, a report from one of the automated services that uses online data to identify features of interest close to the property.

We talk about the health issues with properties near power lines further down this page but if you want to get to those issues quicker see:
our one-page "EMFs At A Glance"    or     download our pdf "EMF The facts".

Firms offering such services include (we neither endorse nor recommend against any of these, we just note their existence):

  • Homeinfo / Envirosearch
  • Groundsure

These searches and reports will often report the presence of electricity equipment - overhead lines or substations.  That may cause some concern to you, or may cause your surveyor to consider whether to adjust the value of the property.

However, these searches often report a substation or an overhead line that is at a distance far too far for EMFs even to be detectable, let alone a cause for serious concern.  EMFs fall rapidly with distance from the source.  It's impossible to be precise because every line or substation is different, and the definition of when we consider that the field has fallen to "background" or "negligible" levels is not straightforward.  But we could say that the field is unlikely to be significant once it has fallen to the levels found in ordinary homes that aren't near any particular sources: anything from 0.01 - 0.2 µT in the UK - let's say 0.1 μT as a single guide figure.

On that basis:

Largest overhead lines on steel pylons – 400 and 275 kV

 thumbnail of L12 thumbnail photo of L6 pylon

Field nearly always falls to levels in ordinary homes within 150 m (perhaps 90-110 m for a typical line, but it depends a lot on the line)

Overhead lines on smaller steel pylons – typically 132 kV

 thumbnail photo of 132 kV pylon thumbnail of 132 kV single circuit line

Field nearly always falls to levels in ordinary homes within 100 m (perhaps 30-60 m for a typical line, but it depends a lot on the line)

Overhead lines on wood poles – typically 33 kV or 11 kV

 thumbnail photos of 33 kV wood poles thumbnail photo of 33 kV wood poles thumbnail of distribution wood pole

Field typically falls to levels in oridnary homes from a few metres to a few tens of metres depending on the line

Large substations

 thumbnail of national grid substation

Field normally falls to levels in ordinary homes within a few metres of the perimeter fence

Small final distribution substations

 sub-final-outdoor-92-wide sub-final-indoor-h92-wide sub-built-in-h92photo of pole mounted substation

Field normally falls to levels in ordinary homes within the first metre or two from the perimeter

(in each case, we are talking primarily about the magnetic field - the electric field has even more limited effect inside homes.)

Other distances you may hear mentioned: epidemiological studies have come up with the field level 0.4 μT as a level where any risk for childhood leukaemia may appear.  That's higher than the average field in UK homes, so not surprisingly, the distance for the field to fall to that level is smaller - 60 m on average for 400/275 kV lines, perhaps 30 m for 132 kV lines.  On the other hand, 200 or 600 m are distances that came out of one specific study, the "CCRG" study, but that is probably less of a concern because of later results from that study where the finding seems to have gone away.

See more pictures to help you identify what a particular bit of the electricity system is.

The reason people flag up the presence of a power line or substation at all is because of scientific evidence about the possibility of a link to childhood leukaemia.  But even if the overhead line or substation is close enough for it to produce an elevated field, that should not necessarily constitute a problem.  The field will still be compliant with the exposures limits that are in place to protect the public.  Each person will wish to make up their own mind, but there seems little reason from an EMF perspective why such homes should not be bought and sold like any other.  But if the home is beyond the distances suggested above, the fields should be negligible and EMFs should probably not need to be a factor at all.

For a summary of the issues relating to the science, see:

our one-page "EMFs At A Glance"    or     download our pdf "EMF The facts".

See also:

  • the policy on EMFs in the UK
  • more on property and power lines in the UK
  • more on sources of exposure

 

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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Specific questions

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  • Microshocks
  • Pacemakers and other medical devices
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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