IEC 60670-1:2015 applies to boxes, enclosures and parts of enclosures (hereafter called "boxes" and "enclosures") for electrical accessories with a rated voltage not exceeding 1 000 V a. c intended for household or similiar fixed electrical installations, either indoors or outdoors. Please make sure. Amendment No. 3 to BS 7671:2008 (IET Wiring Regulations Seventeenth Edition), which was published in January and comes into effect on 1 July, will include a new regulation requiring consumer units and similar switchgear assemblies in domestic premises to have a non-combustible enclosure.