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Installation & Application（安装应用） Function and Application Scope
KHB Series SPD Backup Protector is connected in series between power lines and surge protective devices (SPDs). It can trip immediately during power-frequency faults or SPD failure short-circuits to prevent SPD overheating and fires, while remaining non-tripping during allowable lightning current surges to achieve safe lightning protection.
The KHB Series SPD Backup Protector has various specifications coordinated with surge protective devices (power SPDs) according to lightning protection levels. T1-grade products can withstand 10/350μs waveform lightning current impacts, while T2-grade products are suitable for coordination with 8/20μs waveform power SPDs. Customers can select the appropriate model based on lightning protection system design requirements.
The KHB Series SPD Backup Protector (abbreviated as SCB) is an external overcurrent disconnector specifically designed for series connection in SPD circuits. Using its internal current-selective channel structure, it enables:
Instant tripping for power-frequency low-current short circuits
Non-tripping for high-current lightning surges
This dual functionality:
Prevents SPD short-circuit failures and fires
Withstands major lightning strikes, allowing SPDs to continuously protect power lines
Important Note: SCB products are exclusively for overcurrent/backup protection in SPD circuits and must not be used in other applications.
Product Overview
According to standards such as GB/T 18802.11 and GB 50057, surge protective devices (SPDs) connected in parallel to power lines must have a specified overcurrent protection device connected in series on the upper end of the circuit. Conventional current fuses and miniature circuit breakers cannot distinguish between power frequency current and surge lightning current in power lines, making them incompatible with SPDs. Large-sized current protectors are bulky and inconvenient to install, and they often fail to disconnect quickly during abnormal power frequency conditions or SPD degradation, which can lead to SPD breakdown, fire, or even equipment damage. Smaller current protectors, while compact, cannot withstand sustained high-current lightning strikes, potentially causing damage to power supplies or electrical equipment or failing to provide continuous lightning protection. These issues severely impair the proper functioning of power surge protection systems.
In response to the current state of lightning protection equipment and relevant national standards, our company has developed the KHB series of backup protectors (SCBs), which are designed to coordinate with surge protective devices (SPDs). These protectors are connected in series between the power line and the SPD. They can trip immediately in the event of power frequency faults or SPD failure/short-circuiting, preventing overheating and fires in SPDs, while remaining stable under permissible lightning current surges to ensure effective lightning protection.
The KHB series SPD backup protectors come in various specifications to match different lightning protection levels and surge protective devices (power SPDs). The T1-grade products can withstand 10/350μs waveform lightning current surges, while the T2-grade products are suitable for use with 8/20μs waveform power SPDs. Customers can select the appropriate model based on their lightning protection system design requirements.
The KHB series SPD backup protectors feature a rational design, reliable performance, and a compact form factor that fits the standard spacing of a protection module, ensuring easy installation and use.
Product Dimensions
DIN rail mounting
Wiring and Installation Schematic Diagram
Technical Parameters（技术参数） | Parameter | KHB-I-25R | KHB-80R | KHB-40R |
|---|---|---|---|
| Product Class | T1 Class | T2 Class | T2 Class |
| Impulse Withstand (Imax) | 25kA (10/350μs) | 80kA (8/20μs) | 40kA (8/20μs) |
| Short-Circuit Rating (Ics) | 50kA | 20kA | 20kA |
| Rated Operating Voltage (Ue) | 230V AC | ||
| Rated Insulation Voltage (Ui) | 400V AC | ||
| Trip Current (Ii) | 3±1A | ||
| Load Break Time (To) | ≤100ms | ||
| Mechanical Life | 1000 operations | ||
| Enclosure Protection | IP20 | ||
| Remote Contacts | ON: 11-14 (NC), 11-12 (NO) OFF: 11-12 (NC), 11-14 (NO) | ||
| Torque | 2 N·m | ||
| Min. Cable Size | 2.5 mm² (flexible) | ||
| Max. Cable Size | 25 mm² (flexible) | ||
| Enclosure Material | PA 66 (UL94 V-0) | ||
| Tripping Temp. Range | -40°C to +70°C | ||
| Storage Conditions | -40°C to +80°C, RH <95% (at 25°C) | ||
| Operating Conditions | -40°C to +70°C, RH <95% (at 25°C) | ||
| Color | Black (body), Orange (handle) | ||
| Mounting | EN 60715 (35mm DIN rail) | ||
| Dimensions (W×H×D) | 81mm × 81mm × 65mm | ||
Ordering and Model Selection（订货选型） KHB-I-25R is suitable for Type 1 (T1) surge protective devices (SPDs);
KHB-80R is suitable for Type 2 (T2) SPDs;
KHB-40R is suitable for Type 2 (T2) SPDs.
(The suffix "R" indicates remote signaling capability (optional).)
*Please send the inquiry email containing specific product requirements (such as model, quantity, technical parameters, etc.) to the designated email address salina@kejia.com.
（请将包含具体产品需求（如型号、数量、技术参数等）的询价邮件发送至指定邮箱 salina@kejia.com）
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