Cable access into the metal consumer unit must maintain the integrity of the non-combustable consumer unit so far as reasonably practicable. This can generally be achieved by the installer ensuring that cable access holes they make in the enclosure do not to leave gaps greater than: · 1.0 mm for the horizontal top surface and · 2.5 mm for all other surfaces of the enclosure that are accessible after installation. For rear cable access, the minimum number of knockout(s) shall be removed and a cable protector fitted; see illustration above. Tests on hager consumer units have indicated that there is no specific need for external fire rated cable glands or intumescent sealing in addition to the guidance below, with respect to achieving a non-combustible enclosure. However this does not preclude the designer/installer from using fire rated cable glands or external intumescent sealing should they consider necessary. Internal intumescent pads shall not be used.