The standard addresses the installation of dc power systems within controlled or limited access areas that convert commercial ac to dc voltages of 160 volts or less and those that convert from one dc level to another of 160 volts or less. This standard identifies reasonable means of minimizing hazards associated with the interconnection of dc power systems. Compliance with the standard will not assure the absence of hazards or harm resulting from the installation@ interconnection@ or operation of dc power systems. Not Covered Alternating current distribution and equipment that is part of the telecommunication power distribution system will not be covered by this standard. This standard will not address individual pieces of equipment such as standby ac equipment@ dc to ac inverters@ power supplies@ or power supplies embedded in telecommunications equipment. Purpose This document is a standard for use in the design@ engineering@ installation@ and acceptance of dc power systems for telecommunications environments. Application The dc power system protection standard shall be applied to the engineering@ installation@ and acceptance of centralized dc power systems owned or operated by exchange and interexchange carriers. This standard is not intended to be a specification or an instruction manual for untrained persons. The wire sizes in this standard are based on copper conductors. If other materials are used@ the size shall be adjusted accordingly. DC power systems existing prior to the date of this standard shall not be required to comply with its requirements.