Electrical wiring colours - PC World Oct 30, 2009Infact an electrical certificate is required for any hardwiring in a NZ house and can prevent a house being sold without this certificate. Imagine a fire is started and the house burns down? The insurance company will not pay out if you do not have certificates for any wiring. My brother inlaw is an electrician and refused to do any wiring in our house (just back from Oz) untill he had his NZ license. House Electrical Wire Color Chart - Ask-The-Electrician The Electrical Wire Identification System. To enable wires to be easily and safely identified all common wiring safety codes follow a structured color scheme for the insulation of electrical wire. There are local rules and exceptions that exist based upon the exact application.