This is often seen by the home inspector as the supply conduit to outside installations, such as air-conditioning compressors.

Knob-and-Tube

Knob-and-tube wiring is so named because of the porcelain fittings used to support and insulate the conductors from the timber components in the home. The knob holds the wire away from rafters and joists, while the tubes are inserted into holes bored though joists and studs to protect the conductor and its rubber insulation.

The purpose of bonding is to ensure the electrical continuity of the fault current path, provide the capacity and ability to conduct safely any fault current likely to be imposed, and to aid in the operation of the over-current protection device.

What Is Grounding?

Generally speaking, the difference between grounding and bonding is: Grounding is a direct connection to the earth to aid in removing damaging transient over-voltages due to lightning. The purpose of bonding is to ensure the electrical continuity of the fault current path, to provide the capacity and ability to conduct safely any fault current likely to be imposed, and to aid in the operation of the over-current protection device. Properly bonding all metal parts within an electrical system helps ensure a low-impedance fault current path.