Pepperl+Fuchs K-LB-2.6G Surge Protection Barrier

Product Overview

A high-performance surge protection barrier arrives as the K-LB-2.6G from Pepperl+Fuchs. This 2-channel module mounts directly onto a standard DIN rail, so installation takes only minutes. The K-LB-2.6G works for both Intrinsically Safe (IS) and non-IS applications, which adds versatility. Engineers use this barrier to protect field and control circuit inputs from transients, since these events can damage expensive instruments. Consequently, the K-LB-2.6G safeguards devices with less than 500 V isolation-to-ground. Zener barriers, standard I/O cards, and field instruments all benefit from this protection, yet the barrier remains compact and affordable.

Functional Overview

The K-LB-2.6G limits induced transients from various sources effectively. Lightning strokes, switching impulses, and other electrical disturbances all get suppressed by this device. Specifically, the barrier diverts transient current safely to the ground path rather than letting it reach the instrument. In addition, it limits signal line voltage to a safe level during each surge event, thereby preventing insulation breakdown. Thus, the protected instrument never sees damaging overvoltages, so unplanned downtime decreases substantially. Uninterruptable operation comes from the auto-reset feature, meaning the barrier recovers immediately after each transient event without manual intervention.

Technical Specifications

Surge Protection Specifications

The K-LB-2.6G delivers robust surge handling for industrial environments. Nominal discharge current (8/20 µs waveform) reaches 10 kA per core, while for multiple events, the barrier handles 5 kA per core for 10 surges. Maximum surge current (8/20 µs) reaches 20 kA per core for a single event, whereas for repeated single surges, 10 kA per core applies. Thus, the K-LB-2.6G provides substantial protection for valuable field instruments, so you can operate with confidence.

Nominal response time varies by mode for this barrier. Symmetrical response time measures just 1 nanosecond for fast protection, but asymmetric response time reaches 100 nanoseconds for line-to-ground events. Despite this difference, both modes react almost instantly to dangerous transients. As a result, the K-LB-2.6G clamps surges before they can damage downstream electronics.

Terminal Connections

The K-LB-2.6G uses clearly marked terminals for easy wiring. Protected area connections use terminals 5, 6 and 7, 8, while unprotected area connections use terminals 1, 2 and 3, 4. This clear separation prevents wiring mistakes during installation, thereby reducing commissioning time. Each channel provides a complete signal path with surge protection, so both conductors of each signal pair receive equal protection. Consequently, the K-LB-2.6G maintains signal integrity while shunting surges away.

Ambient Conditions

The K-LB-2.6G operates reliably across a wide temperature range. Standard ambient temperature spans -30°C to +80°C (-22°F to +176°F), yet for Ex applications, you must consult the EC-Type Examination Certificate first. Different temperature classes apply depending on your ambient conditions, so choose the correct class for your installation. For T6 temperature class, ambient must stay ≤ 50°C, whereas for T5 classification, ambient must stay ≤ 70°C. Finally, for T4 rating, ambient reaches up to 80°C maximum, which covers most industrial environments.

Ex-Area Approvals

The K-LB-2.6G carries important hazardous area certifications. EC-Type Examination Certificate number is PTB 00 ATEX 2176X, and additional certificates are available at www.pepperl-fuchs.com. Group and category rating is II 2(1)G Ex ia IIC T6, so this barrier suits gas environments requiring intrinsic safety protection. Therefore, you can install the K-LB-2.6G in Zone 1 and Zone 2 hazardous locations with confidence.

Electrical limits for Ex applications are clearly defined. Voltage Ui maximum stays at 6 V for safety, while current Ii maximum stays at 250 mA for intrinsic safety. Thus, the K-LB-2.6G limits energy entering hazardous areas effectively, thereby preventing ignition sources. Consequently, this barrier meets the most stringent safety requirements for explosive atmospheres.

Conformity and Approvals

The K-LB-2.6G meets multiple international standards and directives. Directive 94/9/EC compliance uses EN 60079-0:2012+A11:2013, and EN 60079-11:2012 applies for intrinsic safety requirements. Degree of protection testing follows IEC 60529 standards, so you can trust the IP20 rating. CSA approval for North America uses Control Drawing 116-0187 (cCSAus), while IECEx approval certificate is IECEx BAS 14.0010X for international use. Therefore, the K-LB-2.6G suits installations worldwide with proper certifications, which simplifies global procurement.

Clamping and Protection Performance

The K-LB-2.6G provides low clamping voltage for sensitive instruments. Line-to-line and line-to-ground clamping voltages stay very low, thereby protecting devices with limited isolation-to-ground ratings. Instruments with less than 500 V isolation benefit greatly from this barrier, since they lack robust internal protection. For example, standard I/O cards often lack internal surge suppression, so the K-LB-2.6G provides essential protection.

The barrier limits signal line voltage during each surge event. Surge current gets diverted safely to the ground connection, while the signal continues passing through unaffected. Thus, the protected instrument sees only safe voltage levels, yet normal operation continues uninterrupted. Uninterruptable operation continues because the barrier resets automatically after each surge, so you do not need to replace fuses or reset breakers.

Grounding Requirements

The K-LB-2.6G requires proper grounding for effective protection. Surge protection barriers must connect to a solid and effective ground, or they cannot function correctly. In addition, the barrier must share the same equipotential level as the protected instrument, since ground potential differences create dangerous currents. The ground system must comply with all applicable electrical regulations, so consult local codes before installing the K-LB-2.6G.

Poor grounding will compromise the protection performance significantly. Without a low-impedance ground path, surge current cannot divert safely, which leaves the instrument vulnerable. Consequently, the protected instrument may still see damaging overvoltages, so always verify ground integrity before service. Therefore, use a dedicated ground wire of sufficient gauge for the K-LB-2.6G.

Installation Guide

Follow these steps to install the K-LB-2.6G correctly.

1. Mount the Barrier: Snap the K-LB-2.6G onto a standard DIN rail first.

2. Connect Ground: Attach a solid ground wire to the ground terminal securely.

3. Verify Equipotential: Ensure same ground potential as protected instruments, or issues may arise.

4. Wire Unprotected Side: Connect field wiring to terminals 1, 2 and 3, 4 carefully.

5. Wire Protected Side: Connect instrument wiring to terminals 5, 6 and 7, 8 next.

6. Check Polarity: Maintain correct signal polarity through each channel, since reversal causes errors.

7. Secure Connections: Tighten all terminal screws to specified torque, so nothing loosens over time.

8. Test Ground Continuity: Verify low resistance to earth ground before powering up.

9. Power Up System: Apply power and verify normal operation, then document the installation.

Important: Never operate the K-LB-2.6G without a solid ground connection, or protection will fail. Always maintain proper separation between protected and unprotected wiring, since mixing can defeat the protection. For Ex applications, follow the EC-Type Examination Certificate requirements strictly, as deviations may compromise safety. Finally, test the barrier after installation using appropriate surge test equipment, so you confirm proper operation.

Key Features and Benefits

• 2-Channel Design: Protects two separate signal circuits with one module, saving panel space.

• High Surge Rating: Handles 20 kA max surge current per channel, so even near lightning strikes cause no damage.

• Auto Reset: Restores normal operation immediately after each surge, eliminating manual maintenance.

• Fast Response: 1 ns symmetrical response for lightning protection, which beats slower suppressors.

• Low Resistance: Only 0.3 Ω series resistance per conductor, so signal integrity remains excellent.

• Ex Approved: Suitable for hazardous area installations, thereby expanding application possibilities.

The K-LB-2.6G delivers robust transient protection for sensitive instruments. Consequently, this barrier suits Zener barriers, I/O cards, and field devices in demanding environments. Its frequency response reaches 40 kHz for process signals, so it works with most industrial transmitters. The sensitivity of your measurement system remains unaffected during normal operation, yet protection activates instantly during surges. Environmental tolerance includes -30°C to +80°C temperature range, which covers both cold outdoor sites and warm control rooms.

Package Contents

• One K-LB-2.6G surge protection barrier module

• One product label with certification markings

• One installation instruction sheet

Frequently Asked Questions (FAQ)

1. What types of transients does the K-LB-2.6G protect against?

The K-LB-2.6G protects against lightning strikes, switching impulses, and electrostatic discharges. It also suppresses transients from inductive load switching and nearby faults, so most industrial risks are covered. Therefore, this barrier suits most industrial environments with transient risks, including heavy manufacturing and power generation.

2. Can I use the K-LB-2.6G with 24 V circuits?

No, the K-LB-2.6G has a rated voltage of ≤ 6 V only, so using it on 24 V risks damage. For 24 V circuits, select a different Pepperl+Fuchs surge protection model instead. Using this barrier on higher voltage circuits may damage the device and void the warranty, so check your voltage carefully.

3. Does the K-LB-2.6G require maintenance after a surge event?

No, the K-LB-2.6G features auto-reset operation after each transient event, so no manual reset is needed. The barrier does not need replacement after nominal surge handling, which reduces lifecycle costs. However, after a very high-energy event (20 kA), inspect the barrier for damage, since extreme events may stress the components.

4. How does the K-LB-2.6G compare to standard surge suppressors?

The K-LB-2.6G offers much faster response time at 1 ns vs microseconds, so it catches faster transients. It also provides Ex approval for hazardous area installations, whereas many suppressors lack this certification. Additionally, the DIN rail mounting simplifies installation in control cabinets, so panel builders prefer this design.

5. Is the K-LB-2.6G compatible with all Pepperl+Fuchs Zener barriers?

Yes, the K-LB-2.6G works with all Pepperl+Fuchs Zener barriers rated for ≤ 6 V, so compatibility is broad. The low series resistance of 0.3 Ω minimizes signal loss, which maintains measurement accuracy. Thus, you can add surge protection without recalibrating your measurement loop, saving significant commissioning time.