When inspectors inspect electrical systems, they are looking for any installation errors, shock and fire hazards, and also labeling issues. Since electrical systems can cause injury or fire, making sure that all of the wiring and electrical panels in a home is very important, and this is why home inspectors take special care to identify any defects in the electrical system.

White hot wire One thing to remember is that a general home inspection is a non-invasive visual inspection. Since much of the electrical wiring in a home is hidden from view, and installed behind wall and floor coverings, inspectors use specific inspection techniques to determine the general condition of an electrical system, and whether there are issues that need repair. Special tools such as GFCI plug testers, voltage detectors, and even infrared cameras can be used to gain a better understanding of an existing electrical system and its condition.

A common labeling issue found in residential electrical systems is improperly labeled white conductors that are being used as hot conductors. So what exactly does that mean? This article will break down why white conductors that are being used as hot conductors should be properly labeled.

In most modern residential buildings, electrical system installers use non-metallic sheathed cables to distribute power throughout the home. Non-metallic sheathed cables typically consist of three separate wires that are protected by a non-metallic sheathing. Two of the wires inside the sheathing have an additional non-conductive layer of material around them, which is usually colored black or white. The third wire is usually bare copper, which is the grounding conductor. In residential electrical systems, wires use a color code so that they can be properly identified. Black is for “hot” wires, which supplies electrical current, and white is for “neutral” wires, which are meant to allow current to flow back to the electrical panel to complete the circuit.

Electrical Wiring - Three Conductors For 120 volt circuits, which include wall plugs, lighting and other small appliance circuits, these three wire cables are used since they only require one hot wire, one neutral wire, and one grounding wire. Therefore the wire color code is sufficient for 120 volt circuits. It is also common to find three wire cables for higher load 240 volt circuits, such as for electric dryers, water heaters and ranges. 240 volt circuits utilize two hot wires since they draw more current, so when a three wire cable is used, the white wire is no longer a “neutral”, wire, but is a “hot” wire.

Current building standards now requires four wire cables for 240 volt circuits, and in this case there are three insulated wires, colored black, red, and white. Black and red are “hot” and white is “neutral”. But in older systems, 240 volt circuits may only have three wires and the white wire is used as a “hot’ conductor.

When a white wire is used as a “hot” conductor, it should be labeled as such on both ends of the wire, so that any technician working on the wiring can properly identify the wires that are “hot”. When inspectors inspect electrical panels, they will often notify the client if white wires that are being used as hot conductors are not properly labeled as such. Usually installers will mark the white wire with red or black marker or tape to properly identify the circuits.

Proper labeling of electrical systems is very important to protect technicians and electricians. An improperly labeled electrical system should be further evaluated and properly labeled by a licensed electrical contractor.

Check out the video below to learn more about hot and neutral wiring in residential electrical systems: