Power Distribution Cabinet

FAQ Guide

The main application of power distribution cabinets is power distribution, but it can also be used to measure energy consumption. It is sold on the market in different types and configurations. It is best to understand the differences between the different types so that you can select switchgear based on your planned use and needs.

But it can also be used to measure energy consumption. It is sold on the market in different types and configurations. It is best to understand the differences between the different types so that you can select switchgear based on your planned use and needs.

But it can also be used to measure energy consumption. It is sold on the market in different types and configurations. It is best to understand the differences between the different types so that you can select switchgear based on your planned use and needs.

1. What is a power distribution cabinet?

Power distribution cabinets are divided into power distribution cabinets, lighting distribution cabinets, and metering cabinets, which are the terminal equipment of the power distribution system. The motor control center is also known as the power distribution cabinet.

Power distribution cabinets are used when the load is scattered and there are few loops; motor control centers are used when the load is concentrated and there are many loops. They distribute electrical energy from circuits in upper distribution equipment to nearby loads. Equipment at this level shall provide protection, monitoring, and control of the load.

2. The purpose and characteristics of the distribution cabinet

Cabinets for housing electrical equipment can solve different problems, depending on how well they perform. The main function is to receive and distribute power and to provide short-circuit protection for power consumers in case of a sharp increase in network voltage.

The operation of the device is carried out by:

• Current variable or constant value;
• Voltage indicator 380 V or 220 V;
• The frequency response range is 50 Hz to 60 Hz.

The distribution cabinet is structurally composed of three parts:

• Metal enclosure – the shape can be made into a square or a rectangle, and the structural size can also be set differently, depending on what equipment is to be installed inside. Cabinets designed to solve special production problems are usually larger in size;
• Fasteners for power receivers and power distributors. Internal installation of machines, voltage stabilizers, receiving metering and control devices, power distribution devices, voltmeters, fuses, ammeters, and other devices specified by the design;
• Various fasteners for mounting DIN rails, cable ducts, pipes, etc.

The distribution cabinet also has a technical hole for pulling cables into the box. The diameter of the hole is used for wiring, the purpose of which is to connect to an appliance that distributes the incoming current. In the simplest design for laying cables and securing terminal blocks, several DIN rails or pipes are installed.

3. Types of distribution cabinets

Power cabinets are divided according to several criteria;

1) Number of functions

Equipment designed for narrow task configurations: mounted on heating systems

Multifunctional: switchboards are used to supply power to machinery and equipment

2) When installing

Ground: mounted on a solid level base

Mounted: Provides technical holes for fixing on vertical planes

Recessed: Typically, these cabinets are custom-made and specifically designed to place the intended equipment in an opening, alcove, or other recess in the wall

3) Provides ease of maintenance

Interior Installation: For Buildings

Outdoor installation: select the power distribution cabinet according to the climate design. Installation is done outdoors

4) Design Classification

Complexities: Apartments, floors, and lighting: are used for energy reception, transmission, and distribution in residential buildings.

Low Voltage Cabinet: Selected for industrial use.

Uninterruptible Power Supply: In the event of an emergency or emergency due to the development of an accident

Power distribution cabinet, powered by two independent power sources: widely used to solve critical production tasks.

Multifunctional device: with its help, reception, metering, energy distribution, and protection in possible emergency situations are carried out simultaneously

4. Dimensions

Work is performed at nominal voltage ratings up to 380 V and electron fluxes up to 400 A. The protection of the discharge line is carried out using fuses. At the inlet and outlet, cables can be placed above or below. The external dimensions produced by the manufacturer are 700*350*1600mm or 500*300*1600mm (the value 1 represents the width, depth, and height parameters).

The operating temperature range of the outdoor distribution cabinet is -45 to +40 0С, and the relative humidity is not higher than 80% at +150С. Operating conditions: no explosion hazard and electrical conductivity, eliminating gas pollution from corrosive substances. Position on the work surface – within 50° of the vertical deviation from the given position. The outdoor distribution cabinet (SHRN) is installed in the production site area or near the residence.

5. What is the internal structure of the distribution box and distribution cabinet?

A motor control center is also known as a distribution box or power distribution cabinet.  The power distribution box is a low-voltage power distribution device composed of switchgear, measuring instrument, protective device, and auxiliary equipment in a closed or semi-closed metal safe or within screen width according to electrical wiring requirements.

The distribution box is a large amount of parameter data, which generally constitutes a low-voltage forest. In a low-voltage distribution box, switchgear, measuring instruments, protective appliances, and auxiliary equipment are assembled according to the requirements of the electrical wiring. In normal operation, a switch can be used to make or break the circuit.

6. The purpose of the distribution box

Reasonable distribution of electric energy to facilitate the operation of opening and closing circuits. It has a high level of safety protection and can visually display the on-off state of the circuit.

Principle of distribution box: The distribution box is a low-voltage distribution box composed of switchgear, measuring instruments, protective appliances, auxiliary equipment, etc. assembled in a closed or semi-closed metal cabinet or within the screen width according to the electrical wiring requirements. The circuit can be turned on or off manually or automatically during normal operation.

In case of failure or abnormal operation, the circuit can be cut off or alarmed by means of protective electrical appliances. Through measuring instruments, various parameters in operation can be displayed, and some electrical parameters can also be adjusted to give prompts or signals for deviations from normal working conditions.

Power distribution cabinets (boxes) are divided into power distribution cabinets (boxes), lighting distribution cabinets (boxes), and metering cabinets (boxes), which are the last level of equipment in the power distribution system. A motor control center is also known as a power distribution cabinet. The power distribution cabinet is used on occasions where the load is scattered and the lines are few.

The motor control center is used in occasions where the load is concentrated and there are many lines. They distribute electricity from the circuits of the superior distribution equipment to the nearest loads. Equipment at this level should provide protection, monitoring, and control for the load.

The power cabinet is an electrical control cabinet that provides power for the normal operation of the whole machine and is composed of contractors, frequency converters, high-voltage cabinets, transformers, etc.

7. Selection Rules

Considering the complex requirements, it is recommended to choose a power distribution cabinet:

• By type – taking into account the main uses and requirements of energy supply system equipment;
• By type of installation – installation is carried out on a solid foundation, on a vertical plane, or built into the intended structure;
• Depending on the current parameters (voltage, short-circuit current, or rated current);
• The degree of protection selected for operation in the expected climatic conditions;
• about climate change.

The selection of distributed hinge guards is recommended based on design decisions, which should include:

• Breaker;
• Number of outlets;
• Lighting switches and devices;
• Food for electrical appliances;
• Cable.

Select the number of distribution closets based on the aggregated load metrics. In order to protect the wires from short-circuit currents, automatic machines are used to switch to rated currents.

The capacity of the telephone cabinet should be selected according to the number of cables placed in it. The main criterion for selection is its height, measured in units. Telephone lines can be selected: wall-mounted or floor-mounted wiring cabinets. The latter are available in depths of 600, 800, or 1000 mm. If you need to install an uninterruptible power supply, you should choose a device with a depth of 800 to 1000 mm. It is recommended to install a PBX or switch, which can save 600 mm. For wall cabinets, specify a depth of 450, 500, or 540 mm.

8. The installation requirements of the power distribution cabinet are as follows

• The distribution cabinet shall be made of non-combustible materials.
• When an electric shock is low, open distribution cabinets can be installed at production sites and offices; closed cabinets should be installed in processing workshops, casting, forging, heat treatment, boiler rooms, carpentry rooms, and other places with a high risk of electric shock;
• In dangerous workplaces where conductive dust or flammable and explosive gases are generated, sealed or explosion-proof electrical facilities must be installed.
• The electrical components, instruments, switches, and lines of the distribution cabinet should be arranged neatly, firmly installed, and easy to operate.
• The bottom of the cabinet installed on the ground should be 5~10mm above the ground;
• Operating handles typically have a center height of 1.2-1.5 meters;
• There are no obstacles within 0.8-1.2m in front of the cabinet;
• The protective wire is connected reliably; there must be no exposed electricity outside the cabinet;
• The electrical components that must be installed on the outer surface of the cabinet or on the power distribution cabinet must have reliable shielding protection.

9. Operation specification of power distribution cabinet

1. The power distribution cabinet is the eighth generation of production and normal operation equipment in the ship’s power distribution center. Any unrelated personnel shall not switch the switches on the board.
2. After the generator set starts, use the acceleration switch on the power screen to manually accelerate slowly until the generator enters the normal working state and the voltage and frequency reach the specified value.
3. After the switchboard enters the power distribution state, the speed-up switch of the switchboard and the lock switch of the air circuit breaker shall not be pulled at will, and shall not be used in non-emergency situations.
4. The parallel operation of generators should be carried out in strict accordance with the requirements and regulations of parallel operation conditions, and attention should be paid to the phenomenon of reverse power (reverse current) and failure of parallel operation.
5. When shutting down, the load of the generator should be cut off first and then shut down without load.
6. When connecting to shore power, first cut off all power switches of the shore power panel, check whether the wiring and phase sequence is correct, and then perform shore power conversion. It is strictly forbidden to run with a load.
7. Maintaining the power distribution cabinet regularly will keep it in good working order.
8. When operating the generator distribution cabinet, the engineer should concentrate on the operation and be careful to prevent accidents. Otherwise, he/she will be responsible for the accident.
9. The charging and discharging board is the emergency power distribution cabinet of the ship. Through the instrument on the board, the engineer on duty should be able to grasp the working status of the magnetic saturation voltage regulator and ensure enough low-voltage power is available at all times.
10. During normal navigation, all switches on the power distribution cabinet should be turned on to ensure that the generator can be started at any time when it responds and put into use at any time.

10. The difference between a power distribution cabinet, switch cabinet, and distribution box

In terms of use, distribution boxes are usually used in homes. The power distribution cabinet is multi-purpose in centralized power supply such as industry and building electricity, and the distribution box and the power distribution cabinet are complete sets of equipment. The power distribution box is a low-voltage complete set of equipment, and the power distribution cabinet has high voltage and low voltage. The size of the power distribution box and the power distribution cabinet is different, of course, it is a larger power distribution cabinet.

And in terms of form, the power distribution cabinet of this thing is a vertical cabinet as the name implies, and the distribution box is a box type. Distribution boxes are used to distribute electrical energy. It is mainly used for the control of electrical equipment, power distribution, overload, short circuit, and leakage protection of lines.

Low-voltage distribution equipment is composed of a closed or semi-closed metal safe with electrical wiring, measuring instruments, protective devices, and auxiliary equipment to form a power distribution cabinet.

During normal operation, there are many types of circuit distribution cabinets. When a fault occurs or the operation is abnormal, the circuit is cut off or the alarm is given by means of a protective device. It can display the operating conditions, adjust some electrical parameters, and indicate or send out signals for deviations from normal working conditions.

The power distribution cabinet can be equipped with various explosion-proof electrical appliances or combinations of explosion-proof electrical appliances, such as explosion-proof power (lighting) distribution box, explosion-proof electromagnetic starter, explosion-proof power inspection box, etc.

Circuit breakers, contactors, thermal relays, buttons, and indicator lights can be installed in the box, which can be used for lighting and power motor control. That is, a distribution box can be installed in the distribution cabinet. The functions are relatively extensive and diversified. Commonly used in power generation, distribution plants, etc. The performance of power distribution cabinets and switchgear is very different.

The switchgear is a complete set of switchgear and control equipment, which serves as the power center and main power distribution device. It is mainly used for the control, monitoring, measurement, and protection of power lines and major electrical equipment. It is often installed in substations, power distribution rooms, factory areas, and other places.

11. Conclusion

To accommodate receivers and other equipment, distribution cabinets are installed, installed at production sites, residential buildings, and power plants. This design allows you to solve many important problems, but only if the cabinet model is selected correctly.