This unit distinguishes between Earth Facility and earth bonding point - An earth facility (EF) usually distributes the electrical mains earth or a dedicated ESD earth (protective earth) within an EPA. An earth bonding point (EBP or common Ground Point) ties together several elements of an EPA such as bench surface, floor mat or wrist strap. In this manner, all are kept at the same electrical potential. In an EPA there may be several EBP but there must be only one EF.