New 400kV cable worries London residents

Residents in Edgware, London, are concerned that a new 400kV power cable under the A5 may breach new limits on electromagnetic fields.

The cable, which will run through a £200m National Grid tunnel from Elstree to St John’s Wood, will come into use next year.

At the end of last month, the National Radiological Protection Board lowered the public safety limits for electromagnetic exposure to 100mT to match international guidelines. This move was supported by evidence that electromagnetic fields can cause leukaemia and other adverse health effects (for a full report on this subject, see the upcoming April issue of Electrical Review).
The National Grid says residents have no cause for concern, stating the emissions measured on the ground above the cable would be lower than those emitted by an overhead power cable by between 0.2 and 0.4mT.