In the UK, any site subject to a Rise-of-Earth-Potential (ROEP) is referred to as a 'Hot-Site'. The Zone-of-Influence was historically measured as anywhere within 100m of the boundary of the high-voltage compound at a Hot-Site. Depending on the size of the overall site this may mean that parts of a larger site may not need to be classed as 'Hot', or (conversely) the influence of small sites may extend into areas outside of the land owner's control. Since 2007, it is allowable to use the Energy-Networks-Association (ENA) Recommendation S34 ('A Guide for Assessing the Rise of Earth Potential at Substation Sites') to calculate the Hot-Zone. This is now defined as a contour-line marking where the ROEP exceeds 430V for normal-reliability power lines, or 650V for high-reliability lines. The 'Zone' extends in a radius from any bonded metalwork, such as the site earth electrode system or boundary fence. This may effectively reduce the overall size of the Hot-Zone compared to the previous definition. However, strip earth electrodes, and any non-effectively insulated metallic-sheath/armouring of power cables which extend out of this zone would continue to be considered as 'hot' for a distance of 100m from the boundary, encompassing a width of two meters on either side of the conductor. It is the responsibility of the owning Electrical-Supply-Industry (ESI) to calculate the Hot-Zone.