Amend Clause 1 as follows: 1 Scope To modify the second dash as follows: an SELV system with a rated voltage not exceeding 25 V without provision for protective earthing (class III) and a rated current not exceeding 25 A per conductor, or To add the following new text at the end of the existing scope: This Standard does not cover operational or performance compatibility between different track systems. Protection against unsafe compatibility between Class I and Class III circuit is covered by this standard The track system may be provided with auxiliary circuits for the purpose of a control or audio signal other than supply. Note: at present on the market the following types of control systems are available - Control signal, basic insulated to LV Supply (e.g.Digital Addressable Lighting Interface, 1-10V DC signal) - Control signal, SELV/PELV insulated to LV Supply (e.g.DMX) - Control signal, not insulated to LV Supply (e.g. push button control / phase cut / step dim) Track systems may also be provided with conductors specifically identified for emergency lighting luminaires. Note: Requirements for PELV are under consideration awaiting modification in IEC 60598-1