LEARN ABOUT THE BUSWAY – POWER ROD SYSTEM THAT REPLACES POWER CABLES

General information:
  Busway:

In essence, Busway conductors, used to replace power cables, are made in the form of bars with hard sheaths and the conductors are converted into copper or aluminum cores, covered with insulating material. The guide bars have a maximum length of 3 m, are connected by connectors, and can have a power location depending on the design and installation location in the building.
There can be many types of guide shafts in a building, but in general there are 3 types as follows:

– Connection from Transformer to main distribution cabinet (LV Panel) (horizontal rise)
– Connect from Generator to main distribution cabinet (LV Panel) (horizontal rise)
– The rod shaft leads from the Distribution Cabinet to the vertical rise
– There may also be branches (using T connections)

 Outstanding advantages of conductors compared to cables: 
– Huge electrical conductivity, can be up to 6300A, 7500A
– Low loss and capable of extracting power from 1 guide shaft at many different locations on the guide bar
– High aesthetics, and saves installation area, saves main power distribution cabinet area.
– Finally, with a certain operating current level (1000A for aluminum core, From 1250A or 1600A or more for copper core), the entire usage cost for Busway, will be cheaper when using traditional power cable.
 Manufacturers around the world and Busway sold in Vietnam: 
In the world, guide bars began to be commonly used in the 80s in Europe, America, Japan, and Korea. There are hundreds of professional busway manufacturers, but generally only the following are well known and have products that are widely sold globally:
Schneider, Siemens . LS Cable, GE

In the Vietnamese market, there are currently 8 main Busway suppliers entering Vietnam, and the corresponding market share order in Vietnam in 2020 is LS Cable (Vietnam) – market share of more than 35%, Schneider – market share of 23%. (sx in China), Siemens - market share of 15%(sx in Vietnam). These 3 companies account for 70% entire Vietnamese market share. The remaining 5 companies are ABB (manufactured in China), PPB, DE, Translite, Megaduct.

 Manufacturing characteristics: 

 1. Shell structure: 
Aluminum case: LS Cable (Vietnam), Siemens (Vietnam), PPB (Malaysia), DE (Malaysia), ABB (China)
LS Cable (Vietnam) and DE (Malaysia) use 2-piece powder-coated cast aluminum housing. The remaining brands use 4-piece aluminum cases. When connecting, a 2-piece aluminum case requires two rows of screws and a 4-piece aluminum case requires 4 rows of screws or rivets to fasten. 2-piece die-cast aluminum cases in the world are only available from LS Cable (Vietnam) and DE (Malaysia) (PPB made in Malaysia and Siemens made in China using 4-piece aluminum cases). In principle, when making 4 pieces, it will be very easy, but because you have to connect to 4 rows, you are not sure about the 2-piece aluminum shell (only need to connect 2 rows). Currently, the world's leading brands Siemens, LS Cable, GE, DE, Cutler Hammer have all switched to aluminum shell technology for more than 10 years.
Iron shell: includes Henikwon, Translite, Megaduct
+ Iron Aluminum Case: Schneider (manufactured in China), offered for sale in Vietnam. 2 pieces of aluminum + 2 pieces of iron.
Due to the superior advantage of aluminum cases over iron cases, large companies have eliminated iron cases, and have been manufacturing aluminum cases for 5-6 years. Do:
– Iron is much heavier than aluminum, so when hanging, the aluminum shell guide ensures more safety
– Iron radiates less heat than aluminum, so when using iron shells, the guide system is hotter and consumes more energy, the nominal current is reduced compared to the design.
– Iron conducts much less electricity than aluminum, so use iron shell as grounding pole, will only be able to reach a maximum of 50%E. While using an aluminum case that reaches over 100% E.
 2. Conductive core structure: 
The conductive core, in principle, can only be aluminum (AL) or copper (CU), purity up to 99.99%.
The characteristic of Copper is that the conductivity is greater than 99%, aluminum is 63-67%, so in return, when using Aluminum, bars with larger cross-sections must be used (but still lighter, and cheaper, when the same current works).).
So between Copper and Aluminum, which type should customers choose ?
Previously, due to habits from Power Cables, most customers in Vietnam used Copper. From the end of 2007 until now, due to updating world market information, the number of projects using Aluminum Busduct has increased significantly.
Copper cables are flexible so they are malleable, but conductors do not need to be bent, so using aluminum cores in commercial buildings is most suitable, because the larger size is not significant, but the overall price is cheaper. 30% – 50% (depending on whether the included accessories are more or less, since the labor cost of the accessory is generally the same for both Copper Busway and Aluminum Busway).
The manufacturer has classified the projects that should use Copper as: Hospitals, data centers, semiconductor factories, research and high-tech centers,... All commercial buildings should use Aluminum due to its efficiency, cost savings, and guaranteed longevity like Copper conductor bars.
In addition, due to manufacturing characteristics, some companies only have Aluminum duct buses up to 4000A, not 5000A, or 6300A, in this case, it is often recommended to use Copper to avoid competition with other brands when the companies The other has a large type of Aluminum busduct (customers do not benefit from offers like this, but you have to pay a lot for the Dong duct bus when using a large operating line).
In Korea, Japan, and Europe, almost 100% of commercial buildings use Aluminum, which is both 30% cheaper and lighter, but the loss compared to Copper is insignificant, the pressure drop is almost equivalent.

 3. Structure of insulating material: 

This is a controversial issue among companies, and whichever company produces it says its type is best.
According to the provisions of IEC 60439-1/2, the temperature of the conductor must not exceed 95 degrees Celsius (and must not exceed 55 degrees Celsius above the ambient temperature, nor exceed 90 degrees Celsius). All brands use insulating materials that exceed this standard:
Therefore, the use of the popular heat-resistant material 130 degrees Celsius is far ahead of the IEC standard. In addition to heat resistance, different types of materials also have other properties. Polyester film (PET) 130 degrees Celsius, Mylar 150 degrees Celsius, Epoxy from 130-180 degrees Celsius (depending on additives).
Conductive conductors were used starting around 1980. At that time, the insulation material was Polyester (large version, then folded, tape). but can be used well for Europe, Korea, and Japan (air humidity lower than 60%).
After that, the American Dupont Group produced Mylar material for companies to use to roll into the guide bar from 2-3 layers. This material reduces the moisture content of the guide rod. However, due to the nature of this material, the insulation is not high (after installation, it only reaches 5-12 Mega Ohm). So American manufacturers researched and introduced Epoxy as an insulating material for conductors. And it is mandatory for companies selling in the US to use Epoxy. Due to the following outstanding characteristics:
– Mylar's double insulation (after installation reaches from 20 – 50 Mega Om)
– EPOXY lifespan reaches 50-70 years (Because Epoxy is a traditional insulating material and the lifespan is confirmed), But Mylar, no one dares to confirm the lifespan, but in reality it has been over 40 years and Mylar still works well.
– EPOXY adheres tightly to the guide bar into 1 block, very good waterproof ability. However, when the guide rod was soaked in water, both Epoxy and Mylar suffered problems.
But manufacturing Epoxy by the fluidizing method requires a technological line, and the secret to preparing Epoxy + additives, to adhere tightly to the guide rod, and have ductility. Therefore, only American Epoxy technology can meet the requirements. GE, SIEMENS, SCHNEIDER, Cuttler Hammer all have to produce Epoxy in the US (only Schneider adds Mylar options for customers). LS Cable, because it wants to export globally, should buy American EPOXY technology, and hire all EPOXY engineers (American, Dutch) who have worked for GE and Schneider in the US to Korea to convert to technology. Epoxy follows American technology. After 3 years of mass sale, this technology from LS Cable proves to be of very high quality and similar to GE USA. At the same time, LS Cable (manufactured in HQ) and GE (manufactured in the US), due to manufacturing Epoxy insulation materials and 2-piece die-cast aluminum housing, should achieve the highest short circuit current of 1s and 3s in the world, up to 200kA for 4000A series or higher (confirmed by Asta and Kema centers, and recorded in catalogs). (Note:GE made in China is being offered for sale in Vietnam with a 4-piece aluminum case, and uses mylar, the short circuit resistance is much lower than GE made in the US)

 4. Conductor bar shape:

The world standard guide bar in sandwich type has 4 heat-emitting wings. All brands follow this way, except Translite, Mega Duct has a square shape, without heat wings.

 5. Included accessories: 

All brands are the same, only LS Cable has one of the most advanced connectors in the world (with mount, to limit, this mount can be pressed down so that the guide bar can penetrate 2.5mm deeper on each side. and can be connected 2.5mm away from this mount. So LS Cable is very flexible and does not need an accessory called Extension (to compensate for length).
Among the accessories, there is a very important mechanism: equipping the MCCB 3P and 4P for the power box. Siemens equipped with MCCB with Icu=70kA or higher, Ics=100% Icu, made in Germany. LS Cable is equipped with standard Icu type from 50kA or more, Ics=100% Icu, Susol series, made in Korea (can use 80kA type according to your request, additional price is insignificant). Other brands see the use of Icu=25kA, Ics=50% Icu (ie short circuit resistance equal to ½ design, made in Asia).

 6. Commonly used Busway standards and current IP: 
In the world and Vietnam, busways are commonly used:
– 3P+100%N+100%E =housing (can 200%N, add internal 50%, 100%E)
– Aluminum Housing
– Conductive core Copper or aluminum ( CU or AL)
– IP 54
– IEC 60439-1/2
– Test short circuit ASTA, or TTA
(The world's IP 42 type has almost been eliminated, but is still maintained in poor, low-standard countries. This type allows dust less than 1mm in size to still penetrate the guide bar, and is less waterproof than IP 54. The cost of manufacturing IP 54 is absolutely not significantly higher than IP 42, but if the technology line is changed, it is not easy, or glue is added to the joining locations, labor will arise.
Type IP 65 is rarely used.
There is also a Cast Resin IP 68 duct bus for outdoor use, which can be soaked in water, or underground. Due to the entire interface and shell, the connectors are poured with Epoxy into a block.