The body of the device is constructed from conductive materials: aluminum and carbon. These materials are coated with non-conductive lacquer or anodized aluminum. However, this doesn't necessarily imply that they serve as effective electrical protective layers. Therefore, relying on them for electrical protection is not assured. Equipotential bonding is made to protect operators against electric shock. It does not allow two different device chassis to have different voltages on them. Connecting these chassis with a conductive wire will bring those chassis to the same voltage potential and protect the operator against electric shock (and protect against ESD as well). Voltages of both chassis will be equal and the operator won't get hurt by touching both of those devices at the same time. The point of equipotential bonding is the ground terminal of the building. This is because the electrical network is (in TT, TN, TNC, and TNC-S cases) tied to the ground. If a dangerous voltage appears on the device chassis, the error current will flow through the ground fault circuit interrupter (GFCI) and switch off the voltage.
