3.5mm 3.81mm PCB Screw Terminal Block — 300V 10A Industrial Wire Connector
3.5mm & 3.81mm PCB Screw Terminal Blocks — 300V/10A Industrial-Grade Wire Connectors
The 3.5mm and 3.81mm pitch PCB screw terminal blocks (KF128-3.5 / KF128-3.81 series) represent the entry point into industrial-grade PCB wiring, rated at 300V and 10A — double the voltage and current capacity of 2.54mm mini terminal blocks. These are the standard choice for PLC I/O modules, industrial sensor wiring, motor driver boards, relay control panels, and building automation systems where reliable, field-wireable connections to 24–12AWG wire are required in a compact PCB footprint.
Key Technical Specifications
- Pitch: 3.5mm and 3.81mm (0.138" / 0.15")
- Rated voltage: 300V (UL) / 130V (IEC)
- Rated current: 10A (UL) / 10A (IEC)
- Wire range: 24–12AWG (0.2–2.5mm²)
- Contact material: Tin-plated copper alloy
- Insulator material: PA66 (UL94V-0)
- Mounting: Through-hole PCB, spliceable
- Pin count: 2P, 3P (spliceable to any count)
- Certifications: CE, RoHS
Complete Product Range in This Collection
This collection includes: KF128-3.5mm terminal blocks (2P, 3P, spliceable), KF128-3.81mm terminal blocks (2P, 3P, spliceable), and multi-pitch assortment kits (2.54mm / 3.81mm / 5.08mm / 7.62mm combinations in 9-value ×10pcs kits) for prototyping and repair. All are through-hole PCB mount with spliceable side-by-side stacking capability.
Ideal Applications
- PLC digital and analog I/O module wiring terminals
- Industrial sensor (4–20mA, 0–10V) signal wiring on control boards
- Motor driver and stepper controller power and signal connections
- Relay and contactor control panel PCB wiring
- Building automation (BMS/HVAC) controller I/O terminals
- Solar inverter and battery management system (BMS) signal wiring
- Industrial IoT gateway and edge controller PCB connections
3.5mm vs 3.81mm — Which Pitch Should You Choose?
3.5mm pitch is the European standard (IEC 60998 / Phoenix Contact MKDS 1.5/N-3.5 equivalent) and is the most common pitch for compact industrial terminal blocks. 3.81mm pitch (0.15") is the North American standard (equivalent to Phoenix Contact MKDS 1.5/N-3.81) and is widely used in US-designed industrial equipment. Both pitches accept the same wire gauge range (24–12AWG) and have the same 300V/10A rating. Choose based on your PCB footprint — the two pitches are not interchangeable on the same PCB.
PCB Screw Terminal Block Buying Guide
Step 1 — Confirm pitch: Measure the center-to-center distance between adjacent screw holes on your PCB. 3.5mm and 3.81mm are close but not interchangeable. Use a caliper for accurate measurement.
Step 2 — Wire gauge: 3.5mm/3.81mm terminal blocks accept 24–12AWG (0.2–2.5mm²). Strip 6–7mm of insulation for optimal clamping. For wire larger than 12AWG, use 5.08mm or 7.62mm pitch terminal blocks.
Step 3 — Spliceable configuration: Order 2P or 3P modular units and snap them together to achieve any pin count. This allows flexible inventory management — stock 2P and 3P units to build any configuration from 2P to 20P+.
Step 4 — Voltage rating: At 300V UL rating, these terminal blocks are suitable for 24VDC, 48VDC, and 120VAC control circuits. They are not rated for 230VAC mains connections — use 5.08mm or 7.62mm pitch blocks rated 300V IEC for mains wiring.
Why Choose Yoeruyo for 3.5mm/3.81mm Terminal Blocks?
Yoeruyo stocks both 3.5mm and 3.81mm pitch terminal blocks in spliceable 2P and 3P units, CE and RoHS certified, with tin-plated copper contacts for reliable long-term connections. Our terminal blocks are dimensionally compatible with Phoenix Contact MKDS 1.5 series PCB footprints. Available in packs of 50pcs and 100pcs, with assortment kits for prototyping.
Frequently Asked Questions
Q: Are 3.5mm and 3.81mm terminal blocks interchangeable on the same PCB?
A: No. 3.5mm and 3.81mm are different pitches with different PCB footprints. They cannot be substituted for each other. Always verify your PCB footprint before ordering.
Q: What is the maximum wire size for 3.5mm/3.81mm terminal blocks?
A: Maximum wire size is 12AWG (2.5mm²). Strip 6–7mm of insulation. For larger wire (10AWG or heavier), use 5.08mm or 7.62mm pitch terminal blocks.
Q: Can these be used for 230VAC mains wiring?
A: The UL rating is 300V, but IEC rating is 130V. For 230VAC mains connections, use terminal blocks with a 300V IEC rating (typically 5.08mm or 7.62mm pitch). Always verify local electrical codes before use.
Q: What screwdriver is needed?
A: A flat-blade screwdriver with a 2.5–3.0mm blade width is recommended for 3.5mm/3.81mm terminal block screws.
Q: Are these compatible with Phoenix Contact MKDS 1.5 footprints?
A: Yes. KF128-3.5mm is dimensionally equivalent to Phoenix Contact MKDS 1.5/N-3.5, and KF128-3.81mm is equivalent to MKDS 1.5/N-3.81. PCB footprints are interchangeable.
