What Is a DIN Rail Terminal Block? Types, Mounting & Sizes

By the Antong Engineering Team · Reviewed August 2026 · 12 min read

A DIN rail terminal block is an insulated connection component that clips onto a standardized metal rail inside a control cabinet, distribution panel, machine, or equipment enclosure. It gives installers an organized place to terminate, isolate, test, fuse, ground, and distribute conductors without drilling a mounting hole for every connection.

The name describes two things at once: the block's electrical function and its mounting method. "DIN rail" does not automatically tell you whether the clamp is screw, spring, push-in, or bolt type, nor does it tell you whether the block fits every rail profile. Those details must be confirmed from the product drawing.

After more than 35 years of manufacturing terminal blocks, we still see the same practical mistake: a buyer specifies a block by its wire range but forgets to specify the rail profile, end-stop system, jumper family, or PE connection method. This guide explains the complete selection chain — rail profile → terminal function → mounting and accessories → current and wire size → application fit.

Quick answer: A DIN rail terminal block clips onto a standardized support rail, most commonly TS35/TH35. The main types are feed-through, protective-earth (PE), multi-level, multi-conductor/distribution, and function terminals such as fused, disconnect, test, diode, and indicator blocks. Select one by matching the rail profile, terminal width, current and voltage ratings, conductor range, environmental conditions, and compatible accessories. TS35, TS32/G32, and TS15/TH15 rails are different profiles — never assume that a block designed for one will fit another.

In this guide

1. What “DIN rail” means

2. Types of DIN rail terminal blocks

3. Mounting and assembly

4. Sizing and current capacity

5. DIN rail terminal block vs panel-mount terminal

6. FAQ

7. Next steps

What Does “DIN Rail” Mean?

A DIN rail is a shaped metal support rail originally associated with German standardization and now used worldwide for modular electrical equipment. The rail carries the mechanical load of the terminal row; it is not, by itself, the current-carrying path of every terminal installed on it.

The most relevant dimensional family is IEC 60715 / EN 60715. Product catalogs commonly use names such as TS35, TS32, and TS15, although exact profile designations can vary between manufacturers. The three profiles below are a practical starting point:

These names are not a compatibility promise. A TS35 × 7.5 rail and a TS35 × 15 rail share the 35 mm top-hat width but have different depth profiles. A terminal foot designed for TS32 or TS15 may not lock correctly onto TS35. Always compare the rail cross-section in the terminal block drawing with the actual rail installed in the cabinet.

Rail and terminal materials

The support rail is commonly made from formed steel with a zinc or similar protective coating. The coating helps resist corrosion and can be important to the mechanical and electrical performance of protective-earth systems. Stainless steel rails are used where corrosion resistance is a priority. Aluminum or copper rails exist for special assemblies, but they are not automatic substitutes for a steel DIN rail.

The terminal's current bar is a separate component. It may be brass or copper, with plating and screw materials specified by the manufacturer. For example, Antong catalog documentation identifies brass conductors and zinc-plated steel screws in relevant feed-through and brass-bar families. Do not infer conductor compatibility or PE performance from the rail material alone.

Important distinction: A rail can support a terminal mechanically without being approved as an electrical protective-earth path. A PE terminal must have a designated metal foot, approved rail contact, or separate protective conductor connection according to its product documentation and the applicable installation rules.

For the background on terminal block construction and other mounting families, see our terminal block types guide.

Types of DIN Rail Terminal Blocks

The rail is the platform. The terminal type determines what the connection does.

Feed-through terminals

A feed-through terminal is the basic DIN rail workhorse. One clamping point accepts the incoming conductor and another accepts the outgoing conductor; the internal current bar joins them. Screw clamps offer broad conductor flexibility and familiar installation. Spring-cage and push-in versions can reduce re-tightening work and wiring time when their conductor requirements are met.

The terminal's body color, shape, and width usually identify a modular family. Accessories such as end covers, partition plates, markers, and jumpers must come from the same family or be explicitly approved as compatible.

Protective-earth terminals

PE terminals are normally green-yellow or otherwise clearly marked. Unlike an ordinary feed-through block, a PE terminal must provide a defined protective connection. Depending on the design, the current path may be through a metal mounting foot that contacts the DIN rail, through a dedicated screw or clamp, or through a separate protective conductor connection.

Never assume that placing a green-yellow block on a painted or poorly bonded rail creates a valid earth path. Verify the rail material, surface finish, contact point, end-stop arrangement, and certification in the datasheet. Antong's earthing brass bars category includes brass-bar assemblies with DIN rail holders; the catalog shows PA/PE holder options and multiple hole counts. Confirm the exact model's current and certification before design release.

Multi-level and function terminals

Multi-level terminals save rail length by stacking circuits vertically, but they require more attention during installation. Check that both levels remain accessible with the cabinet door closed, that the wire bend radius is acceptable, and that the upper level does not obstruct test points or labels.

Fused, disconnect, test, diode, and indicator terminals add a circuit function without giving up the modular rail system. They are especially useful when maintenance requires isolation or measurement without removing the field wires. The presence of a fuse holder or disconnect link does not remove the need to check the terminal's continuous current, short-circuit conditions, and voltage rating.

Mounting and Assembly

Correct DIN rail assembly is more than snapping blocks onto a strip. The terminal row needs mechanical restraint, compatible accessories, correct spacing, and a clear wiring path.

A practical assembly sequence

1. Confirm the rail profile and length. Match the rail cross-section to every terminal foot, end bracket, PE terminal, and accessory in the row.

2. Cut and deburr the rail. A rough cut can damage the terminal foot or leave sharp edges inside the enclosure. Remove swarf before assembly.

3. Install an end bracket or end stop. One end stop establishes the reference point; the completed row should be restrained at both ends or according to the manufacturer's instructions.

4. Clip terminals onto the rail. Engage the mounting foot fully. A block that appears seated but is not locked can move when wires are inserted or removed.

5. Build the row side by side. Keep the correct order for feed-through, PE, function, and spare terminals. Add partition plates where voltage separation or the product drawing requires them.

6. Install jumpers and markers. Use only jumpers designed for that terminal series, pole pitch, and current. Fit labels while access is easy.

7. Inspect before wiring. Check end-stop security, block alignment, PE contact, enclosure clearance, and the route for incoming and outgoing conductors.

End brackets, partition plates, and jumpers

End brackets prevent a terminal stack from sliding along the rail. Partition plates provide extra separation at the end of a group or between circuits with different voltage levels. End covers close exposed sides of a terminal and may be required for touch protection or the declared creepage distance.

Jumpers and commoning bars are not universal. A jumper designed for a particular modular series may have the wrong pitch, pole count, or current rating for another series that looks similar. A jumper can also connect circuits that were intended to remain isolated. Verify the circuit diagram and the accessory datasheet before installation.

Labeling and service access

A dense terminal row is only useful if it can be identified and serviced. Leave enough space for markers, screwdriver access, wire bend radius, and test equipment. Multi-level blocks need a clear labeling strategy for both levels. Keep high-current conductors and sensitive signal circuits organized so that later maintenance does not require removing unrelated wires.

Sizing and Current Capacity

A DIN rail terminal's size is determined by more than the rail width. The key values are wire range, rated current, voltage, terminal width, clamp technology, and the conditions around the row.

Current ratings by cross-section

The following values are an orientation guide for common IEC-style feed-through classes. They are not universal ratings. The same wire cross-section can have a different terminal rating because the current bar, clamp geometry, housing, temperature-rise test, and installation conditions differ.

Under IEC 60947-7-1, rated current is established by temperature-rise testing at the declared rated cross-section. Start with the manufacturer's declared value, then apply any ambient-temperature, grouping, enclosure, or installation derating. See our terminal block current and wire-size selection guide for the calculation sequence.

Wire entry and connection technology

The terminal must accept the actual conductor, not only the nominal cable label. Check:

• minimum and maximum conductor cross-section;

• solid, stranded, or fine-stranded compatibility;

• ferrule requirements and finished ferrule diameter;

• strip length and insertion depth;

• screw, spring-cage, push-in, or bolt termination method;

• whether one or two conductors are permitted in the same clamp.

For flexible wire, a correctly crimped ferrule can improve insertion and strand retention, but it changes the effective conductor diameter. Push-in terminals often require a solid or ferruled conductor for tool-free insertion. Never copy a current value from a neighboring product with a similar body width.

Width, heat, and rail capacity

Terminal width determines how many positions fit on the rail and how much space is available for the current bar and insulation. Narrow blocks improve density; wider blocks generally provide more room for large conductors, heat dissipation, and creepage distance. If many adjacent terminals carry current simultaneously, mutual heating can require grouping derating.

For a 1-meter rail, the rough position count is:

usable rail length ÷ terminal width per position

The usable length is less than 1,000 mm after end brackets, clearance, partitions, and reserved space are included. Treat the result as a layout estimate, not a final bill of materials.

DIN Rail Terminal Block vs Panel-Mount Terminal

DIN rail and panel-mount terminals are not competing technologies in every application. They solve different mechanical problems.

Choose DIN rail when the cabinet needs a modular terminal schedule, repeatable assembly, clear labeling, or future expansion. Choose panel mount when the connection is a fixed multi-pole strip, when the enclosure has no suitable rail, when a custom spacing pattern is required, or when the conductor and lug arrangement is better supported by a bolted body.

A single panel can use both. For example, DIN rail feed-through terminals can handle control and field I/O, while a panel-mounted high-current distribution component handles the main feeder. Antong's feed-through terminal blocks cover the general connection range, while the complete product catalog allows buyers to compare feed-through, brass-bar, and other terminal families.

FAQ: Frequently Asked Questions

Are all DIN rail terminal blocks compatible with TS35 rail?

No. Many modern modular terminals are designed for TS35/TH35, but TS35 itself includes different height profiles, and some terminals are made for TS32/G32 or TS15/TH15 rails. Compatibility depends on the mounting foot, rail dimensions, locking geometry, and the manufacturer's approval. Compare the rail cross-section and terminal drawing before ordering; do not rely on the phrase “DIN rail” alone.

How many terminals fit on a 1-meter DIN rail?

It depends on the terminal's width per position and the space reserved for end brackets, partitions, labels, and wiring clearance. Use floor(usable rail length ÷ terminal width). For orientation, a 6.2 mm-wide block would occupy about 161 positions on 1,000 mm before end hardware; the actual usable count is lower. A 10 mm-wide block would occupy about 100 positions before allowances. Use the exact width in the product drawing for the final layout.

What is the difference between TS35 and TS32 rail?

TS35/TH35 is a 35 mm top-hat profile used widely in current control cabinets. TS32/G32 is a different, approximately 32 mm G-profile rail. They have different cross-sections and mounting interfaces, so a TS35 terminal is not automatically compatible with TS32. TS35 × 7.5 and TS35 × 15 are also different height profiles. Confirm the rail and terminal-foot dimensions together.

Can a DIN rail terminal block carry protective earth through the rail?

Only when the PE terminal is specifically designed and approved for that connection method. A standard feed-through block on a metal rail is not automatically a protective-earth terminal. Check the PE marking, metal foot or dedicated earth connection, rail surface, bonding method, and certification in the datasheet.

Next Steps: Choosing the Right DIN Rail Terminal Block

A reliable DIN rail assembly starts with a complete specification, not just a rail name. Before requesting a quotation or sample, record:

• rail profile and height: TS35/TH35, TS32/G32, TS15/TH15, or another approved profile;

• terminal function: feed-through, PE, multi-level, fused, disconnect, test, or distribution;

• conductor material, cross-section, construction, ferrule, and strip length;

• continuous and peak current, working voltage, ambient temperature, and grouping conditions;

• terminal width, rail length, end-stop space, labeling, and required accessories;

• target-market certifications and any enclosure, vibration, flammability, or corrosion requirements.

Antong has manufactured terminal blocks since 1989, operating a 55,000 m² production facility with ISO 9001 quality management and shipping to 70+ countries. Browse the all products catalog, compare feed-through terminal blocks, and review earthing brass bars for DIN-rail-holder and brass-bar options. Request drawings and samples before approving the final bill of materials.

Continue reading

• Terminal Block Types: The Complete Guide with Pictures

• Screw vs Spring vs Push-in Terminal Blocks: How to Choose

• How to Choose Terminal Blocks: Current Rating, Wire Size & Pitch

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References & standards

1. IEC 60715 / EN 60715, Dimensions of low-voltage switchgear and controlgear — Standardized mounting on rails — IEC Webstore

2. IEC 60947-7-1, Low-voltage switchgear and controlgear — Part 7-1: Ancillary equipment — Terminal blocks for copper conductors — IEC Webstore

3. UL 1059, Standard for Terminal Blocks — UL Solutions

4. WAGO, Material Specifications (PA66/PBT/PC; CTI, RTI, UL 94) — wago.com

5. Phoenix Contact, Terminal Block Material Tests (glow-wire, ball-pressure, flammability) — phoenixcontact.com

6. Antong product documentation — safetypass.com

Technical content prepared by the Antong Engineering Team from 35+ years of terminal block manufacturing experience. Rail dimensions, current values, compatibility, and accessory combinations are orientation guidance; the specific product datasheet and applicable installation standard always control the final design.