Specify and Install Isolated Phase Busbars Correctly for Safety in 2023

Isolated phase busbar systems provide safe, protected power distribution for medium and high voltage applications. This guide covers proper specification, selection, and installation of isolated busbars.

Founded in 1992, GRL is one of the leading brands in China’s low-voltage electrical market. Over the years, GRL has accumulated extensive R&D and manufacturing experience in solar systems, convergence boxes, fuses, fuse switches, DC fuse switches, isolators and busbar systems.

GRL has the ability to independently develop new products and provide OEM and ODM services to help clients gain a competitive advantage. Welcome to contact us.

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Introduction to Isolated Phase Busbars

Isolated phase busbar consist of current carrying conductors enclosed in an earthed metal housing for each phase. Key benefits:

  • Allows use of medium voltage busbars up to 38kV
  • Prevents phase-to-phase faults
  • Simplified installation vs shielded cables
  • Modular, compact, flexible design

Applications include power plants, offshore platforms, mines, heavy industry, and large buildings.

Isolated vs Non-segregated Busbars

Non-segregated busbars at medium voltage can experience phase-to-phase arcing faults. Isolated busbars prevent this by encapsulating each phase separately.

Other differences:

  • Isolated bus bars need no air clearances between phases
  • Isolated bus requires less space than open busbars
  • Individual phase enclosures limit faults
  • Isolated design facilitates installation

For medium voltage, isolated busbars are inherently safer.

GRL-busbar system

Components of Isolated Busbar Systems

Isolated busbar systems consist of:

  • Copper or aluminum conductors sized to current rating
  • Enclosure for each phase, typically aluminum or stainless steel
  • Phase spacing barriers between enclosures
  • Joints, elbows, devices to connect runs
  • Terminations to connect equipment
  • Accessories like gauges, taps, drains

Proper selection of components ensures an effective isolated busbar system.

Design and Selection Considerations

Consider these factors when selecting isolated busbars:

  • Voltage rating up to 38kV
  • Current rating based on loads
  • Enclosure material and ingress protection rating
  • Phase spacing for voltage level
  • Indoor, outdoor, harsh environment ratings
  • Straight runs or complex layouts

Larger busbars cost more but handle higher capacities. Select ratings wisely.

Safety Standards and Testing

Isolated busbar systems should conform to:

  • IEEE C37.23 – Metal enclosed bus
  • IEC 61439 – Low voltage switchgear standards
  • Relevant local electrical codes

Thoroughly type test busbar designs for:

  • Dielectric withstand level
  • Temperature rise limits
  • Short circuit ratings
  • Mechanical strength

Testing ensures electrical and mechanical integrity for safety.

Installation Best Practices

Correct isolated busbar installation requires:

  • Proper phase spacing as specified
  • Secure mounting of enclosures
  • Adequate termination clearances
  • Tight connections to prevent arcing
  • Careful inspection for defects
  • Documentation of installation details

Use certified installers to ensure safe installation per the manufacturer specifications.

Maintenance of Isolated Busbar

Routine maintenance involves:

  • Inspecting for damage, overheating
  • Testing dielectric withstand levels
  • Checking connections are tight
  • Verifying phase clearances
  • Documentation of testing and inspections

Proactive maintenance prevents major issues.

Get Expert Isolated Busbar Solutions from GRL

GRL provides:

  • Technical guidance on isolated busbar system design
  • Quotes for standard and custom isolated busbar
  • Global sales and support for your isolated busbar needs
  • Turnkey solutions including design, manufacturing, testing and installation

Contact GRL today for help with your next isolated phase busbar system.

Frequently Asked Isolated Busbar Questions

Q: What is an isolated phase busbar system?

A: It encapsulates conductors from each phase separately for safe medium voltage distribution.

Q: Why use isolated phase busbars vs non-segregated?

A: Isolated busbars prevent phase-to-phase faults and need no air clearances.

Q: What are the main components of isolated busbars?

A: Conductors, enclosures for each phase, joints/fittings, terminations, accessories.

Q: How do I calculate the current rating for isolated bus?

A: Consider conductor material, size, temperature rise and ambient temperature.

Q: What safety standards apply to isolated busbars?

A: IEEE C37.23 the main standard. Also IEC 61439 and local codes.

Q: What phase spacing is required for isolated bus?

A: No air spacing between enclosures is required due to isolation.

Q: How do I select the right isolated busbar enclosure?

A: Consider material, ingress protection class, size to fit conductors.

Q: What are the advantages of isolated busbars?

A: Safety, reduced footprint, ease of install, flexibility, enclosed protection.

Q: How much does an isolated busbar system cost?

A: $100-$300 per foot typically, depending on ratings and construction.

Q: What are the applications for isolated phase bus?

A: Power plants, mines, heavy industry, offshore platforms, large buildings.

Q: How do you properly install and terminate isolated bus?

A: Follow manufacturer guidelines on spacing, mounting, connections.

Q: What maintenance is required for isolated busbars?

A: Routine inspection, testing, cleaning. Check for damage, overheating.

Q: Where can I find suppliers of isolated busbar systems?

A: Large busbar manufactures like GRL provide isolated busbar solutions.

Q: Is special training required to work with isolated bus?

A: Yes, certified training on medium voltage safety is required.

Q: How are isolated busbars different from bus ducts?

A: Isolated bus is fully enclosed. Bus ducts allow ventilation inside.

Q: Can isolated busbars be installed outdoors?

A: Yes, outdoor isolated bus uses weatherproofing and UV protection.

Q: How long is the typical delivery for isolated busbar?

A: Usually 8-12 weeks depending on complexity. Enclosures can take longer.

Q: What ratings are available for isolated busbars?

A: Up to 38kV voltage, thousands of amps current capacity.

Q: Is isolated busbar only for high voltage systems?

A: It can be used at any voltage to provide phase segregation.

Q: How can I reduce costs when selecting isolated bus?

A: Optimize busbar size to rating needed. Use off-the-shelf solutions where possible.

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