Fire-resistant Low-voltage Enclosed Busway

Short Description:

The refractory busway is suitable for three-phase four-wire and three-phase five-wire supply and distribution systems with AC 50~60Hz, voltage 660V and below, rated current 250~3150A with high fire protection requirements. The product is made of insulating material with high temperature resistance above 500℃, while the heat insulation layer is made of heat insulation and temperature resistant material above 1000℃, and the shell is made of steel. The fire-resistant busway has passed the 950°C, 90-minute to 3-hour high-temperature fire test, as well as the full-load current-carrying test and the waterproof test, and the full set of standard tests for busways, so the selection of this busway can ensure the current-carrying capacity and the stability of power supply for fire-fighting equipment. This series of products can maintain power supply for a certain period of time in case of fire to ensure enough time to start fire-fighting equipment, smoke exhaust and ventilation, and evacuate people.

Product Detail

Product Tags

Product Parameters

Executive standard IEC61439-6,GB7251.1,HB7251.6
System Three-phase three-wire, three-phase four-wire, three-phase five-wire, three-phase five-wire (shell as PE)
Rated frequency f (Hz) 50/60
Rated insulation voltage Ui (V) 1000
Rated working voltage Ue (V) 380-690
current (A) 250A~6300

Product Technical Parameters

  • NHCCX series busways are in compliance with IEC60439-1~2, GB7251.1-2, JISC8364, GB9978 standards for each performance.
  • The busway can withstand 2500V frequency withstand voltage for 1min without breakdown and flashover.
  • The busway is able to withstand strong electric and thermal stresses due to the use of high-strength ceramic as the phase separation material. According to the data in Table (2), the busways passed the dynamic and thermal stability test and showed undetectable ^ deformation after the test.
Rated working current(A) 250 400 630 800 1000 1250 1600 2000 2500 3150
Short-time withstand current(A) 10 15 20 30 30 40 40 50 60 75
Peak withstand current(A) 17 30 40 63 63 84 84 105 132 165
The temperature rise of the conductive parts of the busway trough does not exceed the values listed
in the following table when the rated current is passed for a long time
conductive part Maximum allowable temperature rise(K)
connection terminals 60
Housing 30

Product Selection Table

Current level(A) Name NHKMC1 Fire-resistant busway/4P NHKMC1 Fire-resistant busway/5P
Dimension Wide(mm) High(mm) Wide(mm) High(mm)
250A 192 166 213 166
400A 192 176 213 176
630A 195 176 213 176
800A 195 196 213 196
1000A 195 206 213 206
1250A 195 236 213 236
1600A 208 226 232 226
2000A 208 246 232 246
2500A 224 276 250 276
3150A 224 306 250 306
Current level(A) Name NHCCX Fire-resistant busway/4P NHCCX Fire-resistant busway/5P
Dimension Wide(mm) High(mm) Wide(mm) High(mm)
250A 240 180 261 180
400A 240 180 261 190
630A 243 190 261 190
800A 243 210 261 210
1000A 243 220 261 220
1250A 243 250 261 250
1600A 256 258 280 258
2000A 256 278 280 278
2500A 272 308 298 308
3150A 272 338 298 338
Current level(A) Name NHKMC2 Fire-resistant busway/4P NHKMC2 Fire-resistant busway/5P
Dimension Wide(mm) High(mm) Wide(mm) High(mm)
250A 161 128 164 128
400A 161 138 164 138
630A 161 148 164 148
800A 161 158 164 158
1000A 161 178 164 178
1250A 161 208 164 208
1600A 161 248 164 248
2000A 169 248 173 248
2500A 169 283 173 283
3150A 169 308 173 308


High load-bearing capacity
This type of busway channel adopts steel profile shell, which can carry 70kg of pressure in the center of the 3m span busway, and the center of the plate shell can be shifted by no more than 5mm when the temperature changes non-uniformly.

Long fire resistance time
Fire-resistant series busways are divided into NHCCX, NHKMC1 and NHKMC2 according to the structure type and the form of fire-resistant insulation treatment, and their corresponding fire-resistant limits under energized conditions are shown in the table.

Model Structure form Fire resistance limit(min) Fire-resistant temperature(℃) Applications
NHCCX Dense 60 850 Normal power supply
Firefighting power supply
NHKMC1 Air type 60 900 Normal power supply
Firefighting power supply
NHKMC2 Air type 120 1050 Firefighting power supply


Fire-Resistant Busway (1)

End Cap

Fire-Resistant Busway (8)


Fire-Resistant Busway (6)

Plug In

Fire-Resistant Busway (5)

Plug In Unit

Fire-Resistant Busway (1)

Hard Connection

Fire-Resistant Busway (4)

Vertical Fix Hanger

Fire-Resistant Busway (2)

Vertical Spring Hanger

Fire-Resistant Busway (3)

Expansion Joint

product description04

Flance End Box

Fire-Resistant Busway (10)

Soft Connection


Selection of insulation and refractory materials with excellent performance

  • The mica tape wound by the copper row of busway conductor conforms to JB/T5019~20 "electrical insulation mica products" and JB/T6488-1~3 "mica tape" standards. The mica tape has good flexibility and high heat resistance and good dielectric properties and mechanical properties under normal condition: bending strength ≥180MPa; dielectric strength ≥35kV/mm; volume resistivity >1010Ω-m. When the temperature reaches 600℃, the mica tape still has high insulation performance insulation resistance >10MΩmm2.
  • According to the different fire resistance limit of the refractory busway, the measures taken by the heat insulation layer are also different. If the busway needs to run for a long time with electricity, the heat insulation layer is usually directly insulated with air so as not to affect the heat dissipation during the operation of the busway, and when the busway is not normally energized for emergency power use only, its heat resistance limit is higher and the heat insulation layer needs to be filled with silica wool, the silica wool material selected for this refractory busway conforms to GB3003 "common aluminosilicate refractory fiber mat" standard, its AL2O3+SiO2 content reaches 96%, the continuous use temperature is 1050℃, ^high use temperature reaches 1250℃.
  • When the fire occurs within 3~5 minutes, the coating starts to foam and expand, forming a heat insulation layer, and the thermal conductivity increases rapidly, which effectively reduces the heat transfer. All the performance indexes of the refractory coating used in this refractory busway are in accordance with the national GB14907-94 standard.
  • In order to meet the refractory requirements, the phase separation block and the joint separation block are made of high temperature resistant ceramic material, which has an Al2O3 content of more than 95% and has the following dielectric and mechanical properties under normal conditions: dielectric strength ≥13kV/mm volume resistivity >20MΩ-cm flexural strength ≥250MPa. the ceramic is particularly effective in temperature resistance, and the measured insulation resistance is >10MΩ when the temperature reaches 900°C. Due to the good stability of the ceramic, there is no aging problem of the insulation material, thus effectively extending the service life of the busway.
  • Environmentally friendly products: In case of fire, no toxic gas is emitted from the busway, and no secondary combustion is formed, which is a new generation of environmentally friendly electrical products.
  • Flexible wiring: The busway plug interface is set flexibly, and it is convenient to draw out the branch current. Each plug interface can be inserted into different capacity plug boxes, and the plug box pin guard is also made of high temperature resistant ceramic material to ensure that the power can be drawn out smoothly in case of fire.
  • NHCCX series refractory busway has successfully passed the type test of National Electric Control Equipment Quality Supervision, Inspection and Testing Center and the refractory test of National Chemical Building Material Testing Center, and its electrical performance, mechanical performance and refractory performance are all at the domestic ^ level according to the investigation.

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