The main differences between the primary wiring and secondary wiring of the distribution cabinet are as follows:
Function
Primary wiring: used to realize the transmission, distribution and control of electric energy, directly connected to the power supply and power equipment, responsible for the transmission and distribution of electric energy, and is the main circuit of the power system. For example, the power supply is introduced into the distribution cabinet, the electric energy is distributed to each branch through the busbar, and then the electric energy is transmitted to the specific power equipment through control equipment such as circuit breakers and disconnectors.
Secondary wiring: used to control, measure, protect, and indicate signals for the primary wiring. Through various relays, instruments, control switches and other equipment, the operating status of the primary circuit is monitored and controlled. When the primary circuit fails, an alarm signal can be issued in time or the circuit can be automatically cut off to protect the safety of equipment and personnel.
Voltage level and current size
Primary wiring: usually involves higher voltage levels and larger currents. The voltage may range from hundreds of volts to hundreds of thousands of volts, and the current may range from tens of amperes to thousands of amperes.
Secondary wiring: The working voltage is generally low, usually AC 100V, 220V or DC 24V, 48V, etc. The current is relatively small, generally below a few amperes.
Wiring components
Primary wiring: The main components are circuit breakers, disconnectors, load switches, fuses, current transformers, voltage transformers, busbars, power cables, etc.
Secondary wiring: The main components are relays, measuring instruments, control switches, buttons, signal lights, terminal blocks, control cables, etc.
Wiring methods and wiring characteristics
Primary wiring: Usually single busbar, double busbar, single busbar segmentation, double busbar segmentation and other wiring methods are used. The wiring is relatively simple and direct, with the main purpose of achieving reliable transmission and distribution of electric energy, and the wire cross-sectional area is large.
Secondary wiring: The wiring method is relatively complex, with multiple methods such as radial, trunk, and chain. The wiring requires neatness, beauty, and order, and is easy to maintain and repair. The wire cross-sectional area is relatively small.
Drawing representation
Primary wiring diagram: usually represented by a single-line diagram, which shows the connection relationship between primary devices in a simple and clear way, and is mainly used to represent the main wiring scheme of the power system and the transmission path of electric energy.
Secondary wiring diagram: There are many forms such as schematic diagram, expansion diagram, installation wiring diagram, etc. The schematic diagram is used to represent the working principle and mutual relationship of secondary equipment; the expansion diagram separates the secondary circuit into AC current circuit, AC voltage circuit, DC circuit, etc., which is convenient for analyzing and understanding the circuit principle; the installation wiring diagram is used to guide the installation and wiring of secondary equipment.
