Outdoor medium-voltage circuit-breaking and isolation equipment

Medium Voltage Components

Outdoor vacuum circuit breakers, disconnectors and current and voltage transformers for protection, isolation and measurement. Share your electrical ratings, installation conditions and drawings for a configuration review.

Component Types and Functions

Match each circuit function

  • Interrupt currentCircuit breaker

    Switching and fault-clearing duty

  • Provide isolationDisconnector

    An isolation point in the operating scheme

  • Provide signalsCT or VT

    Current or voltage inputs to meters and protection

Mark each device’s location and function on the single-line diagram, including its connections to the protection and metering circuits.

Circuit breaking and protection

Use
Switch the circuit and interrupt fault current within the specified device ratings.
Review
  • Voltage and current duty
  • Fault level and duration
  • Operating sequence
  • Control and protection interfaces
Coordination
Specify the protection relay, controller and any automatic reclosing functions required with the breaker.
View outdoor breakers

Secuencia de aislamiento y funcionamiento.

Use
Provide an isolation point with the required mounting and operating arrangement.
Review
  • Indoor or outdoor location
  • Current and withstand duty
  • Operation and interlocks
  • Earthing and connection points
Coordination
Isolation does not replace load or fault interruption. Define the associated switching device and operating sequence.
View disconnectors

Current and voltage measurement

Use
Provide current or voltage signals for the specified metering and protection circuits.
Review
  • CT or VT ratio
  • Accuracy and burden
  • Measurement or protection duty
  • Secondary connections
Coordination
CTs and VTs have different primary connections and selection requirements. Confirm each device separately.
View CT and VT equipment

For a complete assembly, review the component requirements together with the panel arrangement, protection scheme and equipment supplied by others.

Explore MV & LV SwitchgearExplore Prefabricated Substations

Component Configuration Guide

Identify the equipment function

Start with the device’s role on the single-line diagram: circuit breaking, isolation, or current and voltage measurement. All fields are optional.

Use the equipment schedule to identify each device, circuit reference and connection.

Review the three equipment families, or continue with the information already available.

Outdoor Vacuum Circuit Breakers Disconnectors Instrument Transformers (CT & VT)

Component Applications

Utility and secondary distribution

Rural overhead distribution feeder with pole-mounted switching equipment

Review overhead-feeder switching, fault interruption and isolation points against the utility scheme. Specify mounting, control supply, protection connections and outdoor conditions for each device.

Explore application

Industrial incoming supply

Medium-voltage protection and isolation equipment beside an industrial facility

Coordinate incoming protection, isolation and metering with the plant single-line diagram. Match the selected devices to the installation space, approved control scheme and maintenance arrangements.

Explore application

Infrastructure metering and protection

Metering panels in an indoor electrical service room

Define the current and voltage inputs required by meters and protection relays. Review CT/VT ratios, accuracy, burden, secondary wiring and indoor installation interfaces together.

Explore application

Renewable plant connection

Medium-voltage circuit-breaking and isolation equipment beside a solar plant

Start with the plant connection requirements and AC collection scheme. Confirm switching duty, isolation responsibilities, protection signals and the environmental conditions at each installation point.

Explore application

Component Quotation Checklist

Equipment & supply scope

Device list
Required equipment families, quantities, circuit functions and any specified models or accessories.
Connection points
Primary terminals, control circuits and CT/VT secondary connections identified on the project diagrams.

Ratings & interface drawings

Requisitos eléctricos
System ratings, switching or withstand duties, control supply and the CT/VT ratio, burden and accuracy schedule.
Installation details
Mounting dimensions, terminal orientation, connection clearances, operating access and site conditions.
Approved interfaces
Confirm outline dimensions and primary, control or secondary-circuit drawings before installation work proceeds.

Inspection & acceptance

Acceptance plan
Applicable standards, inspection points, document schedule and project acceptance criteria.
Test documents
Agree test documents for the specified device and rating combination, together with the records required for the supplied equipment.

Packing & handover

Transport arrangement
Package dimensions, weight, handling points and separately packed mechanisms or accessories.
Dispatch documents
Approved drawings, operating instructions, packing lists and agreed inspection records.
Site responsibilities
Confirm receipt checks, storage conditions, positioning, external connections and pre-energization responsibilities.

Why Choose SUBIA for MV Components

Electrical equipment manufacturing site
Electrical equipment manufacturing site.

Application and equipment review

SUBIA reviews your circuit function, ratings and installation conditions to prepare the proposed equipment configuration.

Interface coordination

Discuss mounting, primary connections, control supply and secondary terminals alongside the equipment and systems supplied by others.

Drawings and inspection documents

Agree the drawing schedule and inspection records during technical review, matching the documents to the devices and ratings being supplied.

Packing and delivery coordination

Review package markings, accessory lists and handling requirements so your team can plan receipt, storage and installation at the site.

Component Selection & Procurement FAQs

How do I choose between a circuit breaker, disconnector and instrument transformer?

Start with the circuit function. A circuit breaker provides the specified switching and fault-interruption duty; a disconnector provides an isolation point; a CT or VT supplies current or voltage signals for metering and protection. Use the single-line diagram to identify each device and its connections.

Can a disconnector interrupt load or fault current?

Do not assume a disconnector has load-break or circuit-breaker capability. Its isolation function must be coordinated with the appropriate switching device and operating sequence. Review any stated switching duty against the exact device specification before use.

Which ratings are needed for an outdoor vacuum circuit breaker?

Provide the system voltage, rated current, prospective fault current and required fault-duty values, frequency and operating sequence. Include control supply, protection connections, mounting and site conditions. Confirm the complete rating combination for the proposed model.

What information is needed for a CT or VT enquiry?

Identify CT or VT, the required ratio, secondary values, accuracy class, burden and metering or protection purpose. Include the wiring arrangement, terminal requirements, insulation level and available mounting space. Review current-transformer and voltage-transformer requirements separately.

How do indoor and outdoor conditions affect selection?

State the installation location, ambient temperature, altitude, exposure and any contamination or condensation concerns. Provide mounting dimensions, connection details and operating access. Indoor devices require an installation arrangement suited to their specified service conditions.

What should I prepare for a quotation?

Send the equipment list, quantities, single-line diagram, known electrical ratings and installation drawings. Add control or secondary-circuit requirements and identify items still to be confirmed. Agree the required drawings, inspection records, acceptance points and delivery documents during review.