segregated phase bus

Segregated Phase Bus Duct- Managing the Low and Medium Voltage Requirements

segregated phase bus

Generation and distribution of electricity is of vital importance for everything nowadays. Every enterprise and every household requires electricity. There are various devices and components which are involved in the production and management of electricity as it is a very complex process. Segregated Phase Bus Duct is one such device which is designed for the low and medium voltage requirements.

The purpose of such designs is to meet specific, continuous and short circuit current ratings and generating stations, substations and industrial distribution systems which can be installed indoors and outdoors. In a segregated bus duct, each phase conductor is separated by a grounded barrier from adjacent phases unlike in non-segregated phase ducts where all phase conductors are in the same enclosure. For conducting large currents between devices, a cable bus is used. For very large currents in generating stations or substations, where it is difficult to provide circuit protection, an isolated-phase bus is used. Each phase of the circuit is run in a separate grounded metal enclosure. The only fault possible is a phase-to-ground fault, since the enclosures are separated. This type of bus can be rated up to 50,000 amperes and up to hundreds of kilovolts (during normal service, not just for faults), but is not used for building wiring in the conventional sense.

One of the greatest advantages of bus ducts is that they are capable of adding or removing a branch circuit without removing voltage from the whole duct. It carries large amounts of amperage across a distance. This is useful in plant design so that you can pull individual leads down from it to machinery. The problem with this is control. If it is installed and the plant does not properly keep up on load documentation, it is easy to overload it. Installing bus duct requires the installer to work with and handle high voltages and currents which can cause instant death. Therefore, it should be done with utmost care and all the necessary precautions should be taken.

Segregated Phase Bus Duct: Ratings Required For It

segregated phase bus

Isolated phase duct is moderately special as compared to the other duct systems termed and needs much more space. It is also considerably more costly to buy and install, but considered a unique system for particular applications and, in specific, as a generator duct feed. Generally, rigid conductor type Segregated Phase Bus Duct length is computed from centre line to centre line, and the tools to which it is attached, to form overall duct-length footage. Bar extensions within a termination cubicle are regarded as part of the termination tool. For cable duct, the same measures are used for establishing the length.

The only exemption is 60 inches of duct length should be added for creating overall length dimensions, because of the cable extension leads vital at every end. Such cable lead extensions are measured part of the duct length, somewhat than part of the termination equipment.


Segregated duct that comprises of cable duct basically has the same constant current ratings, from 600A to 6000A. Duct of higher ratings is delivered up to 12000A; nevertheless this is for special applications needing special design, fabricating and installation considerations. Capacities are usually based on 40°C ambient where conductors have silver plated joints, and the permissible temperature rise of the conductor is 65°C. Noncurrent carrying parts that can be voluntarily touched are allowed a 40°C rise. Ambient temperature range limits are -30°C to +40°C, and height is up to 1000 metres (3300 feet). Other ambient situations require special consideration and may perhaps contribute to de-rating.

Voltage range for these kinds of duct is chiefly from above 600V to 34.5kV to ANSI but to 46kV to CSA. In everyday terminologies, the maximum rating is 38kV with a BIL rating of 150kV. It comprises of cable duct, even though cable at supposedly 38kV can have a higher BIL rating and can undoubtedly have higher insulating voltage class, up to 33 per cent insulation on higher voltage ratings.

Non Segregated Phase Bus: The Difference With The Segregated One And Its Usage

non segregated phase bus

Segregated phase bus and non segregated phase bus are all components and the most integral parts in the electricity. Among all the essential and mandatory sectors present in our society, electrical sector is the most integral one. The constituents and components of it are highly technical and require the person to be acquainted with huge information.

Segregated and non segregated bus ducts are custom designed for both medium and low voltage needs and demands. The bus duct designs meet up the explicit and definite constant and short circuit current ratings of the generating substations, stations and industrial distribution systems that could be installed indoors or outdoors and are manufactured and tested in the GE’s bus duct facility.

Segregated phase bus duct – The Segregated phase bus duct conductors are in an enclosed space save for segregated from each other.

Non segregated phase bus duct – The non segregated phase bus duct conductors are inside an enclosed space however, although not separated out from each other.

Isolated phase bus duct – The three isolated phase bus duct conductors are in three separate enclosures. It is more often than not used for large current applications similar to connecting alternators for stepping up power transformers despite the fact that the other two above are utilized for gas insulated substations.

Non segregated phase bus runs are designed to be used on circuits whose significance or worth needs greater reliability than the power cables make available. They are designed for withstanding mechanical and electrical forces produced by the transitory and short time short circuit currents. Since they are highly useful in various applications, therefore, they are fabricated with the use of fine quality raw materials. And it must be noted that the manufacturers should appoint only the experienced and skilled professionals for manufacturing and producing the best quality non segregated phase bus.