What is a terminal block and how does it work?

A terminal block is an electrical connector that safely joins two or more conductors. It provides secure wiring termination, easy maintenance, and clear identification. Common types include DIN rail terminal blocks, barrier and screw types, and spring-cage or push-in variants.

What is the difference between barrier and spring-cage terminal blocks?

Barrier terminal blocks use a screw clamp for a strong mechanical hold and wide wire compatibility. Spring-cage terminal blocks use a stainless-steel spring for vibration resistance and faster installation, ideal for modern control panels.

What are TS35 and TS15 in DIN rail terminal blocks?

TS35 and TS15 refer to DIN rail sizes. TS35 (35 mm wide) is the standard for most industrial terminal blocks, while TS15 (15 mm wide) is used for compact, light-duty applications. Both comply with EN 60715.

How do I choose the right terminal block?

Select terminal blocks based on current rating, wire size, voltage class, and mounting method (DIN rail or screw). Consider features like double-level or knife-disconnect variants, PE ground terminals, and accessories such as jumpers, markers, and end clamps.

What accessories are used with terminal blocks?

Accessories include terminal block jumpers for bridging, marker strips for circuit identification, and end clamps for securing assemblies. These components ensure clear labeling, safe grounding, and stable installation.

What standards apply to terminal blocks?

Terminal blocks typically comply with UL 1059, IEC 60947-7-1, and EN 60715 standards for safety, material, and mounting compatibility. Always check certification markings before use.

How should a PE (ground) terminal block be installed?

PE terminal blocks should be mounted directly on a metallic DIN rail to ensure low-impedance grounding. The rail must be properly bonded to the panel’s protective earth busbar for effective safety performance.

What are double-level and knife-disconnect terminal blocks used for?

Double-level terminal blocks increase wiring density by stacking two circuits in one footprint. Knife-disconnect types include a switchable blade that allows isolation, testing, or circuit maintenance without removing conductors.

Terminal Block | Connector reliable manufacturer

Willele: Reliable Terminal Block Manufacturer

Willele designs and manufactures a full range of terminal Connector & Block for electrical connection and power distribution. From DIN rail types (JXB, EK, UK, UKH, MRK, EW) to barrier and screw types (8T, LT, WU), our products ensure safe, durable, and efficient wiring across industrial and commercial systems.
Made from flame-retardant PA plastics and high-conductivity brass inserts, Willele terminal blocks offer stable clamping, easy installation, and long service life.
Trusted by engineers worldwide, Willele delivers reliable connection solutions for every power and control application.

Get A Quotation Now!

Compliant with Global Safety Standards

Common Using TERMINAL BLOCK

DIN RAIL TERMINAL Connector & Block

Willele SAK/JXB Terminal Block

Willele MRK Terminal Block

UK Series DIN Rail Connector & Block

UKK SERIES Power Distribution Block

Willele WLB Modular Distribution Blocks

Why Choose Willele

Willele designs and manufactures reliable terminal Connector & Block and wire connectors for electrical connection and power distribution. From DIN-rail series (SAK/JXB, MRK, UK/UKH, UKK, USLKG) to barrier and screw types (LT, 8T, H, W(U)) and our WLE compact splicing connectors, we help panel builders deliver safe, durable, and efficient wiring.

Proven Quality & Compliance
Built with flame-retardant PA housings and high-conductivity brass inserts, Willele products are tested for safety and performance and are supplied to meet global compliance needs (e.g., UL/CE/RoHS/ISO documentation available upon request).
Complete Portfolio
One supplier for feed-through, high-current, double-level, PE grounding, knife-disconnect, power distribution blocks (UKK), and WLE push-in/lever connectors—plus markers, jumpers, and end brackets.
Engineering-Led Innovation
Spring-cage and push-in technologies deliver consistent contact force, reduce installation time, and improve reliability in vibration-prone environments.
Fast, Clean Installation
DIN rail snap-on designs (TS35/TS15), clear color coding, pre-assembled jumper options, and compact footprints keep panels neat and serviceable.
Responsive Service & Value
Application guidance, CAD files, samples, and quick logistics help you select and deploy the right solution—performance you can trust at competitive cost.

GET FULL CATALOGUE

Willele: Reliable Terminal Block & Connector Manufacturer

Willele designs and manufactures a full portfolio of terminal Connector & Block and wire connectors for electrical connection and power distribution. From DIN-rail types (SAK/JXB, MRK, UK Series, UKK, USLKG) to barrier & screw types (LT, 8T, H, W(U)), and WLE quick connectors (push-in & compact splicing), we help panel builders deliver safe, durable, and efficient wiring across industrial and commercial systems. Flame-retardant PA housings and high-conductivity brass inserts enable stable clamping, easy installation, and long service life.

Barrier & Screw Type Terminal Blocks

Willele W(U) Type Terminal Block (12 Pole) – Row-type strip for clean, modular wiring layouts.

Willele LT Type Terminal Block – Barrier-style terminal, robust screw clamp for simple feed-through wiring.

Willele 8T Type Terminal Block (8 Pole) – Multi-circuit barrier strip; neat, compact panel mounting.

Willele H Type Terminal Block (12 Pole) – High-density barrier strip for organized field termination.

Quick Connectors (WLE Series)

WLE Compact Splicing Connectors – Lever-actuated, reusable connectors for lighting loops and junction boxes.

Willele WLE Series Push-in Wire Connectors – Tool-free push-in spring technology for fast cabinet work.

DIN Rail Terminal Connector

Willele SAK/JXB Terminal Connector & Block – Classic DIN-rail screw-clamp series for general control wiring.
Willele MRK Terminal Connector & Block – Modular function terminals for structured panel builds.
UK Series DIN Rail Terminal Connector & Block – Spring-cage solutions for vibration-resistant connections.
UKK Series Power Distribution Block – Compact, color-coded distribution blocks for clean power branching.

Specify Your Terminal Block & Connector

Factory automation, building management & HVAC, machinery OEM, power distribution panels, switchgear, and general control cabinets.

Get a Quotation Now

More Than a Terminal Block Manufacturer

We don’t just ship hardware—we help you build safer, cleaner wiring. From early selection to on-site support, Willele provides fast answers, practical engineering, and dependable delivery so your panel comes together on schedule.

Expert Consultation

From simple feed-throughs to complex cabinets, our engineers assess load, voltage class, conductor size, standards, and environment to specify the right family—SAK/JXB, MRK, UK/UKH (spring-cage), USLKG (PE), or barrier types LT/8T/H/W(U)—with matching accessories. Drawings, datasheets, and cross-references provided.

Product Selection Recommendations

Not sure which terminal Connector & Block fits? Share pole count, wire range, rail type (TS35/TS15), and functions (double-level, disconnect, ground). We confirm exact part numbers, bridging/marker options, and return pricing and lead time—typically within 12 hours.

Logistics & Shipping Support

From export paperwork to carton labeling and palletization, we arrange reliable transport under flexible Incoterms. Expect clear ETAs, tracking, and proactive updates to keep your build on schedule.

Guidance & Support

During installation we advise on strip lengths, tightening torque, end-clamp spacing, bridging and marking schemes, and DIN-rail or panel mounting. For larger projects we offer remote start-up help or on-site assistance.

Knowledge About Terminal Blocks

What Is a Terminal Block?

A terminal block (also called a terminal connector) is a modular device that joins conductors, provides test/label points, and keeps panels serviceable. Common types of terminal blocks include barrier terminal block (classic screw terminal block), spring cage terminal block and push in terminal block, plus function variants such as double level terminal block, knife disconnect terminal, and PE/earth grounding types. See our Wiring Guide and the page-end FAQ.

Main Applications

Control panels, marshalling rows, MCCs & distribution cabinets
Industrial machinery & OEM equipment; building automation & HVAC
Process I/O termination, sensor/actuator routing, and test points
DIN rail terminal block layouts on TS35 / TS15 rails for scalable assembly — learn more about DIN rail basics

Mounting & Rails

A din rail mount terminal block snaps onto standardized rails for fast, repeatable layouts. Choose TS35 (35 mm) for most panels or TS15 when space is limited; some strips can also be panel-mounted when rails are not used. Reference: DIN rail profiles.

Clamp Types — Barrier/Screw vs Spring-cage / Push-in

Barrier / Screw: broad wire compatibility and strong mechanical hold; ideal for general feed-through.
Spring-cage: consistent contact force under vibration with minimal re-torque; great for high-volume builds.
Push-in: tool-free insertion of prepped conductors for the fastest cabinet wiring.

Functional Variants

Double level terminal block: two circuits in one footprint to increase density.
Knife disconnect terminal: visible isolation for testing, loop checks, or safe separation.
Other options: fuse, test, diode, pluggable and sensor/actuator variants for diagnostics and protection.

Grounding (PE) — Safety & Identification

Use a ground terminal block to bond protective earth. A dedicated PE terminal block (green/yellow) ensures a low-impedance path to the earth busbar, sometimes called an earth terminal. Standards overview: UL 1059, IEC 60947-7-1.

Accessories — Bridging, Marking & Retention

Terminal block jumper: distribute common potentials without extra wiring.
Terminal block marker strip: keep circuits traceable; match IDs to schematic tags.
End clamp (end bracket): lock the row on the rail to prevent creep under vibration/cable pull.

How to Select the Right Terminal Block

Use this quick checklist for terminal block selection before ordering:

Clamp style: barrier/screw for versatility; spring-cage or push-in for speed and vibration resistance.
Function: feed-through, double level, knife disconnect, test/fuse, or PE ground.
Mounting: TS35 vs TS15; modular DIN-rail vs panel-mount strip.
Labeling & distribution: plan terminal block jumper positions and marker strip scheme; add an end clamp.
Compliance & docs: request UL/CE/RoHS files; keep installation notes with the datasheet.

Sizing tips (wire range, current rating, strip length, torque) appear in the FAQ.

Specs, Standards & Safety

Ratings: current rating and voltage depend on model and conductor size—always confirm in the datasheet.
Materials: flame-retardant PA housings; copper/brass current bars for low resistance and durability.
Test points: many blocks include integrated ports for commissioning and maintenance.
Environment: choose clamp style for vibration, temperature, and maintenance strategy.

Wiring Best Practices for Terminal Blocks

Strip to the specified length and fully seat the conductor; see the datasheet’s strip length for terminal block.
Tighten to the recommended terminal block torque and perform a light pull test.
Use the correct cavity and ferrule size; avoid double-up unless explicitly allowed.
Plan bridging and marking early: position jumpers and apply marker strips to match the schematic.
Re-check tightness after first energization or vibration exposure; close any covers or shields after testing.

Read the FAQ Contact Us for the Torque & Strip-Length Chart

Terminal Block FAQ

How do I choose a terminal block? (terminal block selection)

Start with the circuit function (feed-through, double-level, disconnect, PE), then match wire range and routing. For terminal block selection consider terminal block sizing against the datasheet wire window, and confirm the required wire size for terminal block including ferrule dimensions if used. Pick clamp technology that suits your build (barrier/screw for flexibility; spring-cage or push-in for speed), and verify accessories such as jumpers, markers and end clamps.

What voltage and current do I need? (ratings & compliance)

The terminal block voltage rating and the current rating depend on the conductor size, clamp type, temperature rise limits and installation group. Use the product table to cross-check rating vs. wire cross-section and the number of adjacent loaded poles. For regulatory files, request UL/CE/RoHS documentation from our team or consult UL 1059 overview.

What strip length and torque should I use? Can I DIN rail or screw mount?

Follow the datasheet’s recommended strip length for terminal block so the conductor fully seats beneath the pressure plate. Tighten to the specified terminal block torque and perform a light pull test. Most families support DIN-rail mounting on TS35/TS15; panel screws are preferred for shock-intense sites—both options are valid, i.e., din rail or screw mount, when confirmed by the installation notes. For a quick checklist, see the Wiring Guide.

How do I use a terminal block jumper and marker correctly?

A terminal block jumper cross-connects adjacent blocks to share a common potential; plan jumper positions to minimize crosswiring and label them on the schematic. Apply a terminal block marker that mirrors your tag naming (e.g., X1:1-X1:20) so commissioning and troubleshooting stay traceable. Lock the row with end clamps after you confirm continuity.

When should I use a ground terminal block? (PE terminal block wiring)

Use a ground terminal block to bond protective earth for metallic enclosures, cable shields, and incoming supply PE. For PE terminal block wiring, select green/yellow terminals with certified earth bonding to the rail or a dedicated PE bus, keep PE conductors as short as practical, and verify continuity from device to main earthing point according to your site code.

TS35 vs TS15 — which rail should I choose? (din rail terminal block sizes)

TS35 (35 mm) offers the broadest ecosystem and higher mechanical stability; choose it for most cabinets and power sections. TS15 (15 mm) is compact for space-constrained devices. Match foot profile and din rail terminal block sizes to the available clearance; use serrated or plated rails for reliable bonding, especially around PE terminals.

Which clamp works best in vibration? (spring cage vs screw in vibration)

In industrial environments with frequent shock or thermal cycling, spring technologies maintain contact force without periodic re-torque. That’s why spring cage vs screw in vibration typically favors spring-cage or push-in for reliability and speed. Screw clamps remain excellent where wire types vary widely or where frequent re-terminations are expected.

Do terminal blocks need maintenance? How do I use a test point?

Spring and push-in designs are effectively maintenance free under normal service. Screw types may need periodic verification per site practice. Many families include a terminal block test point; insert the probe or plug per the datasheet to measure voltage, loop integrity, or current without removing conductors.

Request a Custom Terminal Block Quote

WILLELE supplies OEM/ODM terminal blocks to your spec — DIN rail terminal block (TS35/TS15), barrier/screw and spring-cage/push-in options, double-level, knife-disconnect, and PE ground. Tell us wire size & current rating, pole count, rail type, plus accessories (terminal block jumper, marker strip, end clamp). Fast sampling & stable lead time.

GET INSTANT QUOTE NOW