History of Old electrical wiring identification: photo guide History of electrical wire & electrical wiring: how to recognize knob and tube electrical wiring and unsafe "extension cord" wiring. How to evaluate the number of electrical circuits in an older home. Photo guide to types of old building electrical wires. These photos help identify types, condition, & hazards of old electrical wiring in buildings. Identifying House Electric Wiring Colors | DoItYourself Standard Colors Used for Home Wiring. What follows here is the standard coloring for wires throughout a home. The gauge or size of the wire may change depending on the current requirement of the circuit, but the color is a consistent feature. Black. The wire that carries the current from the power source to the outlet or receptacle is the hot wire. Electrical Wiring Colours - The Old and the New (UK) | EC4U UK Wiring Colours – The Old and the New. Have you checked the colours of the wiring in your home? Are you planning on rewiring your home or taking some electrician courses?Electrical wiring colours were changed in 2006 and it’s important to know what to look for.