1. Scope of application

The SWFHM fireproof busbar is suitable for three-phase four-wire and three-phase five-wire power distribution systems with AC 50-60Hz, rated voltage 660V or less, and rated current 250-3150A, requiring high fire protection requirements. This series of products maintains power supply for a certain period of time in the event of a fire, ensuring sufficient time to activate fire-fighting equipment, exhaust ventilation, and evacuate people, minimizing casualties and property losses.

This product is mainly used in high-rise buildings, important control centers, subways and other public places with large traffic flow and other places with high fire protection requirements.

2. Basic structure of busbar

The bus duct adopts a double-layer shell with good rigidity, high strength and strong load-bearing capacity.

3. Selection performance

The mica wrapped around the bus duct conductor copper bar complies with the JB/T5019.20-85 "Electrical Insulation Mica Products" standard;

The mica tape has good softness, high heat resistance, good dielectric properties and mechanical properties under normal conditions;

Bending strength ≥180MPa, dielectric strength>35kV/mm, volume resistivity, 1010Q.m;

When the temperature reaches 600℃, the mica tape still has high insulation performance; insulation resistance 10MQ/mm2;

According to the different fire resistance limits of fire-resistant busbars, the measures taken for its thermal insulation layer are also different;

If the busbar needs to be powered on for a long time, its insulation layer is usually directly insulated with air to avoid affecting the heat dissipation during the operation of the busbar (see Figure 1);

When the bus duct is not normally powered and is used only as an emergency power supply, its heat resistance limit requirement is higher, and the insulation layer needs to be filled with silicon wool (see Figure 2);

The silicon wool material used in this fire-resistant busbar complies with the standard GB3003-82 "Ordinary Aluminum Silicate Refractory Fiber Felt". Its AL203+Si02 content reaches 96%, the continuous use temperature is 1050℃, and the maximum use temperature is 1250℃.

4. Basic structure of busbar
The busbar housing is sprayed with fire-resistant paint. Within 3-5 minutes of a fire, the paint begins to foam and expand, forming a heat-insulating layer. The thermal conductivity coefficient increases rapidly, effectively reducing heat transfer. The performance indicators of the fire-resistant paint used in this fire-resistant busbar meet the GB14907-94 standard.

In order to meet the fire resistance requirements, the phase partition blocks and joint spacers are made of high-temperature resistant ceramic materials. The ceramic material AL203 has a content of more than 95%. Under normal conditions, its dielectric properties and mechanical properties are as follows: dielectric strength 13kV/mm, volume resistivity>20MQ.cm, and flexural strength 250MPa.

The ceramic is particularly heat-resistant, with an insulation resistance of 10MQ.cm measured at 900°C. Due to the ceramic's excellent stability, there is no aging problem with the insulation material, effectively extending the service life of the busbar.

5. Environmentally friendly products

In the event of a fire, the bus duct will not release any toxic gas and will not cause secondary combustion. It is a new generation of environmentally friendly electrical products.