Load-Break Disconnecting Switches
RH-B Series – 11-33kV – 400-630A – Expulsion Interrupters
Adds expulsion-type arc-interrupting chambers to the standard disconnecting switch. Safely switches load current with manual operation — no separate circuit breaker needed for routine switching operations at distribution voltage levels.
OEM / ODM – Low-MOQ samples – Type-test reports
Overview
The RH-B series load-break disconnecting switch solves a critical operational limitation of standard disconnectors: the inability to switch under load. By adding expulsion-type interrupters (arc chutes) to the main contact assembly, the RH-B can safely break rated load current (400-630 A) with a single manual pull on the operating handle — extracting the arc into a sealed gas-evolving chamber where it is extinguished at the current-zero crossing.
Why this matters for distribution operations: A utility crew needing to isolate a feeder section for maintenance would normally need to (a) trip the upstream circuit breaker, (b) open the disconnector, (c) reclose the breaker. This sequence interrupts all customers on that feeder, even those on healthy sections. With a load-break disconnector, the crew can open the switch under load directly, section by section, without any outage — a dramatic improvement in network reliability metrics (SAIDI/SAIFI).
The interrupters use the same gas-evolving liner principle as fuse cutout tubes: the arc heats a polymer liner, which decomposes into high-pressure gas, blasting and elongating the arc until it extinguishes at the next current zero. The key difference from a fuse cutout is that the link does not melt during normal load-breaking — the interrupter is reusable for hundreds of operations.
Technical Specifications
| Rated Voltage | 12 kV / 36 kV (Um) |
|---|---|
| Rated Current | 400 A / 630 A |
| Load-Break Capacity | Up to rated continuous current |
| Fault-Make Capacity | 12.5 kA peak |
| Short-Circuit Withstand (3s) | 12.5-20 kA |
| BIL Phase-Ground | 75-170 kV |
| Power Freq Withstand | 42-70 kV |
| Interrupter Type | Expulsion, gas-evolving liner |
| Interrupter Life | >=200 load-break operations |
| Contact System | Copper, silver-plated, with auxiliary arcing tips |
| Operation | Manual via pole-mounted handle, 3-phase gang |
| Insulator Options | Porcelain or Polymer |
| Standards | IEC 62271-102 / IEC 62271-103 |
Range
| Model | Voltage | Current | Load-Break | Fault-Make | Insulator |
|---|---|---|---|---|---|
| RH-B-12/400 | 12 kV | 400 A | 400 A | 12.5 kA | Porc./Polymer |
| RH-B-12/630 | 12 kV | 630 A | 630 A | 12.5 kA | Porc./Polymer |
| RH-B-36/400 | 36 kV | 400 A | 400 A | 12.5 kA | Porc./Polymer |
| RH-B-36/630 | 36 kV | 630 A | 630 A | 12.5 kA | Porc./Polymer |
Also available with Loadbuster hook attachment for hot-stick operation. Interrupter replacement kits stocked.
Key Features
Break rated load current (400-630A) with manual operation. No need for upstream breaker tripping — maintain network reliability while isolating sections for maintenance.
Gas-evolving liner extinguishes the load-break arc without consuming the interrupter. Rated for 200+ operations before liner replacement. Spares are inexpensive and field-replaceable.
Can close onto a fault (12.5 kA peak) — critical for re-energizing a line after repair where a fault might still exist. The switch will mechanically withstand the closing surge.
Standard operating handle. Pull once: interrupter breaks the load current, then main contacts separate to provide the visible isolation gap. No special training or multi-step sequence.
For pole-top installations, a standard Loadbuster attachment can be used with a hot-stick for live-line load switching from ground level — no manual linkage or platform access required.
Mechanically interlocked: main contacts cannot open until the interrupter has broken the arc, and cannot close unless the interrupter is in the reset position. Prevents operator error.
Applications
Open and close feeder sections under load for maintenance and network reconfiguration. No customer interruption during switching operations.
Switch between two transformer supplies in a ring-main or loop configuration without dropping load. Critical for hospitals, data centers, and industrial processes.
Routine switching of pole-mounted capacitor banks for voltage support and power factor correction. The interrupter handles the capacitive switching current.
Isolate distributed generation (rooftop solar, small wind) from the grid under load without tripping the generator’s own protection.
Frequently Asked Questions
How is load-break different from standard?
How many times can I load-break before maintenance?
What happens if I try to interrupt fault current?
Can I retrofit interrupters to an existing standard disconnector?
Need Load-Break Switches for Network Operations?
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