Ring Main Unit

XGN15-12 SF6 Ring Main Unit

XGN15-12 is a compact, fixed metal-enclosed ring main unit for indoor 12 kV cable distribution. An SF6 load switch provides the switching function, with load-switch–fuse combinations available for circuits requiring fuse protection. The compact format suits urban networks, building distribution points and sites with limited switchroom space.

The series has a 630 A busbar rating and can be arranged around the required incoming and outgoing circuits. Switching, earthing, interlocking and protection functions are coordinated with the network's single-line diagram, while cable access is matched to the installation layout.

Technical Specifications

Rated Voltage	12 kV
Rated Frequency	50 Hz
Rated Current	630 A
Short-Time Withstand Current	20 kA (3 s, main and earthing circuits)
Peak Withstand Current	50 kA (main and earthing circuits)
Power-Frequency Withstand Voltage	42 kV (1 min)
Lightning Impulse Withstand Voltage	75 kV
Insulation Medium	SF6 (load switch)
Switching Units	Load switch / switch-fuse
Enclosure IP Rating	IP3X
Standards	GB 3906 / IEC 62271-200

Key Features

Fixed SF6-insulated ring main unit design.
For 12 kV medium-voltage cable distribution.
Load-switch / fuse combinations.
Compact footprint for urban networks.

Typical Applications

Urban neighbourhood substations
Rural distribution substations
Industrial and commercial substations

Installation & Aftercare

Prepare the site, plan routine checks and keep service records.

What needs to be ready before installation?

Use an indoor room with space for operating handles, cable termination and removal of the specified fuse assembly.
Match cable connectors and bending space to the ordered panels; provide foundation fixing and site earthing connections.
Keep external cable and mechanism areas dry; the SF6 load switch does not provide environmental protection for the entire room.

What should operators check during routine rounds?

Observe switching and fuse indications, enclosure condition and signs of condensation during rounds.

What is covered during planned maintenance?

At planned isolation, inspect operating and earthing mechanisms, interlocks, fuse contacts and cable terminations; check any fitted gas-condition indication.
Investigate blown fuses or abnormal heating before return to service, using the approved replacement components and switch service procedure.

Customization Options

Define the electrical configuration and the details needed for your site.

Network arrangement: Incoming ring circuits, transformer feeders, terminal supplies and future extension requirements.
Switching units: Load-switch or switch-fuse arrangement; select the fuse combination for the transformer rating and network fault duty.
Protection & metering: Fuse or relay protection arrangement, CT ratios, metering and fault-indication requirements.
Cable interfaces: Cable count, cross-section, termination type and earthing connections.
Controls & enclosure: Operating mechanism, auxiliary supply and remote signalling; enclosure and site conditions for engineering review.

Project-specific options and accessories are confirmed in the quotation and approved drawings.