This site concerns the 50 and 60 Hz fields that are produced by AC power systems. In the UK up to now, DC has been used only really for the undersea interconnector to France. But in the next few years it is quite likely that we will be building some DC connections within the UK. See the Energy Networks Strategy Group report for more information.
DC electricity produces static fields. We summarise here the exposure limits that apply to static fields.
UK limits on magnetic fields
As described here for AC fields, the policy for public exposure in the UK is that we apply the 1998 ICNIRP exposure guidelines in the terms of the 1999 EU Recommendation. That applies to DC fields as well as AC fields. The ICNIRP limit for static magnetic fields is 40 mT. So that applies in the UK, though, in accordance with the EU Recommendation, only where the time of exposure is significant.
In 2009 ICNIRP published new guidelines on static magnetic fields. These raise the public limit to 400 mT. But this probably does not change the situation in the UK which is governed by the 1999 EU Recommendation.
UK limits on electric fields
The 1998 ICNIRP guidelines and the 1999 EU Recommendatioin do not contain any limits for static electric fields. Instead, there is a statement:
"For most people, the annoying perception of surface electric charge will not occur at field strengths less than 25 kV/m. Spark discharges causing stress or annoyance should be avoided."
