GB/Z 44472-2024 Explanation of the mathematical addition of working voltages,insulation between circuits and use of PELV in lighting standards

Scope

This document provides an explanation of the insulation coordination requirements introduced in lighting standards to cover new technologies related to LED light sources and controllable products, including mathematical addition of operating voltages, insulation between circuits, the use of protection extra-low voltage (PELV), and insulation between low-voltage (LV) power supplies and control line conductors. This document describes the way in which the power supply voltage and operating voltage overlap when the first fault occurs, in order to evaluate the electrical insulation requirements of the system (such as creepage distances and electrical clearances). In addition, this document also provides a detailed explanation of the actual failure scenarios given in Appendix X of GB/T 7000.1—2023 and Chapter 15 of GB/T 19510.1—2023, and gives the basic principles of protection requirements for each scenario [for example, a possible failure from the primary LV circuit to the secondary ELV circuit will not lead to an insulation overload in the secondary circuit]. This document also describes the possibility of improving the anti-interference and reliability of electronic circuits when PELV is used together with LEDs, and the related safety consequences of this system. The insulation between LV power supplies and control line conductors is equally important. This document explains why this is a fundamental safety consideration for a complete installation system.

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