DIN Rail Terminal Blocks — Sizes, Torque, Wiring & Selection
DIN rail terminal blocks snap onto a standard 35 mm rail (TS-35) inside a control panel to join wires safely. Choose by rated current, conductor size (mm²/AWG), connection type (screw or push-in), and the certification your market needs (UL 1059 in North America; IEC 60947-7-1 elsewhere).
Which DIN rail? TS-35 vs TS-32 vs G-type
Most modern blocks clip onto TS-35 (35 mm "top hat", EN 60715) in 7.5 mm or 15 mm depth. Older TS-32(32 mm) and G-type rails still appear in legacy gear —check the foot of the block matches your rail before you standardize.
Wire size, current and torque (reference)
| Conductor | ~AWG | Typical current* | Typical screw torque* |
|---|---|---|---|
| 2.5 mm² | 14 | ≤ ~24 A | ~0.5–0.6 N·m |
| 4 mm² | 12 | ≤ ~32 A | ~0.6–0.8 N·m |
| 6 mm² | 10 | ≤ ~41 A | ~0.8–1.2 N·m |
| 10 mm² | 8 | ≤ ~57 A | ~1.2–1.5 N·m |
| 16 mm² | 6 | ≤ ~76 A | ~1.5–2.0 N·m |
*Typical industry values per IEC 60947-7-1 conventions, for guidance only — always confirm against the specific series datasheet. Not a Shining certified rating.
Color codes (industry convention)
By convention, grey = general feed-through, blue = neutral (N), green/yellow = protective earth (PE, which also bonds to the rail). Use consistent colors and printed markers so anyone can trace the panel later.
Jumpers, potential distribution & end stops
Use insertion jumpers (combs) to bridge adjacent blocks at a common potential — the clean way to distribute power without daisy-chained wires. Finish every group with an end plate (covers the live face) and an end bracket / stop so the stack cannot slide.
Derating in dense panels
Current ratings assume room around the block. Packed rails and hot enclosures raise temperature, so derate in dense or high-ambient builds and leave breathing room near high-current blocks.
Failure mode: why torque and flame rating matter
The most common terminal-block failure is a loose connection: as clamping force drops, contact resistance rises, the joint heats locally, the metal oxidizes, resistance climbs further — a thermal runaway that can scorch the block or start a fire. Two defenses: tighten screws to the specified torque(and re-torque on a maintenance schedule), and specify housings rated UL94 V-0 so the body resists ignition and self-extinguishes. Push-in and spring designs remove the torque variable entirely by holding a constant spring force.
How to wire a DIN rail terminal block
- Strip the conductor (use a ferrule on stranded wire).
- Insert into the clamp.
- For screw types, tighten to the specified torque.
- Mark the block.
- Bridge with jumpers where a common potential is needed.
The manufacturer's angle
The clamp structure — a steel cage on screw types, a hardened spring on push-in — is what really determines anti-loosening and service life; cheap stampings relax under vibration and heat. Because our screw and push-in variants share the same footprint, you can switch connection style without changing the rail or the panel. Many series are UL Recognized Components (UL & cUL), File E257927, with UL94 V-0 housings; OEM color/marking and low MOQ (50/100/200) suit small panel shops.
FAQ
What is the difference between TS-35 and G-type DIN rail?
TS-35 is the 35 mm top-hat rail used by most modern blocks; G-type is an older profile in legacy equipment. Match the block's foot to your rail.
How many DIN rail terminal blocks fit per metre?
Depends on block width (pitch): a 5 mm block gives ~200 per metre, an 8 mm block ~125 — leave room for end stops and breathing space.
Do I need an end bracket and end plate?
Yes — an end plate covers the last live face and an end bracket stops the stack from sliding on the rail.
What torque should I use on a screw-type DIN rail block?
Use the value on the series datasheet (typically ~0.5–2.0 N·m by wire size). Under-torque overheats; over-torque damages the conductor.
Can I mix screw and push-in blocks on the same rail?
Yes — they share the rail; with same-footprint families you can also swap connection style without redesigning the panel.