About: http://webisa.webdatacommons.org/92750708

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	2/ this is saying that if you have an external cpc not protected by the conduit or trunking of the wiring system, 4mm is the smallest size if it is not mechanically protected, 2.5mm is the smallest if it is protected.
http://www.w3.org/ns/prov#wasQuotedFrom	theiet.org