The HB950M 3-Position Barrier Screw Terminal Block with Transparent Safety Cover (9.5mm Pitch / 300V 30A) is a heavy-duty, through-hole PCB-mount and panel-interfacing terminal connector engineered for high-current power distribution, AC mains line termination, and industrial power electronics. Featuring a wide 9.5 mm center-to-center pin pitch, heavy-duty brass/copper alloy conductive tinned pins, and M3.5 steel clamp screws with integrated captive square washers, it accommodates standard fork/ring crimp lugs or thick bare wires up to 12 AWG. Fitted with a removable, flame-retardant clear plastic protective flip cover, it provides physical contact protection and dust resistance while maintaining full visual inspection of wiring terminations. The HB950M is widely utilized in switch-mode power supplies (SMPS), motor drivers, audio amplifiers, industrial automation panels, inverter stages, and custom DIY power supplies.

Specifications

• Model / Part Number: HB950M-3P / HB9500-3P Series
• Connector Type: Heavy-Duty Barrier Terminal Block (PCB Solder Mount)
• Number of Positions / Poles: 3 Positions (3-Pin / 3-Way)
• Pitch / Pin Spacing: Standard 9.50 mm (0.374 inch) Center-to-Center Pitch
• Rated Electrical Voltage: 300 V AC/DC (Standard UL rating) / Up to 450 V AC (IEC)
• Rated Electrical Current: Up to 30 A (depending on wire gauge and PCB trace thickness)
• Contact Resistance: ≤ 20 mΩ
• Insulation Resistance: ≥ 500 MΩ (at 500 V DC)
• Dielectric Withstanding Voltage: 2000 V AC (50/60 Hz for 1 minute between adjacent terminals)
• Compatible Wire Gauge: 22 AWG to 12 AWG (0.5 mm² to 4.0 mm² solid/stranded wire)
• Screw Size & Type: M3.5 Nickel-Plated Steel Screws with Captive Square Clamping Washers (SEMS)
• Recommended Screw Tightening Torque: 0.8 N·m to 1.2 N·m (7.1 to 10.6 lb-in)
• Housing Material: High-Grade Flame-Retardant PBT / Polyamide (UL 94V-0 Rated, Black)
• Terminal Contact Material: High-Conductivity Brass / Copper Alloy with Matte Tin Plating
• Safety Cover: Snap-on Removable Transparent Polycarbonate / PVC Protective Dust Cover
• Mounting Style: Through-Hole PCB Soldering (Dual solder pin legs per pole for high mechanical stability)
• Operating Ambient Temperature: -40°C to +105°C
• Dimensions: Approx. 30.0 mm × 22.0 mm × 18.0 mm (L × W × H, including safety cover)
• Weight: Approx. 16 g

Features

• High 30A Current Capacity: Large conductive cross-section and heavy-duty solder pins easily handle high continuous current loads without excessive resistive heating.
• Integrated Transparent Safety Shield: Snap-on clear cover prevents accidental physical contact with live AC mains terminals, prevents short circuits from stray metal clippings, and allows easy terminal inspection.
• Captive SEMS Clamping Washers: M3.5 terminal screws include serrated square pressure plates that clamp both bare stranded wires and crimped lugs securely without fraying individual wire strands.
• Wide 9.5mm Pitch Creepage Distance: Generous spacing between poles ensures high dielectric isolation and prevents flashover or arcing in 230V/250V AC and high-voltage DC applications.
• Rigid Flame-Retardant Construction: High-temperature UL 94V-0 insulating base resists deformation during high-temperature wave soldering and continuous heavy-load thermal cycles.

Common Applications

• Switch-Mode Power Supplies (SMPS): Primary AC mains input (Line, Neutral, Earth) and high-current low-voltage DC output rail connections.
• Motor Drivers & CNC Controllers: High-amperage 3-phase motor terminations (U, V, W) and stepper/servo driver DC power bus terminals.
• Power Inverters & UPS Units: AC transfer lines, battery bank inputs, and high-current relay/switch connections.
• Audio Power Amplifiers: High-power transformer secondary rectification connections and multi-channel speaker output terminals.
• Industrial Control Panels: Interfacing PLC modules, relay banks, heating element controls, and auxiliary power distribution boards.

Usage Tips

• Lug Termination Best Practices: For maximum electrical contact and vibration resistance, terminate stranded wires with standard M3.5 / 6 fork (spade) or ring crimp terminals before inserting them under the square washer plates.
• PCB Trace Sizing for 30A Loads: If running high currents through PCB solder joints, design wide heavy-copper PCB traces (e.g., 2 oz copper with 6 mm+ trace widths) or apply solder bridging/copper bus wire over the exposed PCB trace to handle the full current capacity without thermal throttling.
• Proper Screw Torquing: Tighten the M3.5 screws firmly to approx. 1.0 N·m using a standard Phillips #2 or flathead screwdriver. Avoid overtightening with power drivers to prevent stripping the threaded baseplate.
• AC Mains Wiring Safety: When using this 3-pin block for AC mains power entry, standard wiring conventions are: Pin 1: Line (L), Pin 2: Neutral (N), Pin 3: Earth/Ground (E/PE). Ensure the transparent cover is securely snapped into place before energizing.
• Safety Cover Removal & Installation: The transparent cover can be gently pried off with a small flat blade for wire installation and snapped back over the retention ridges once all screw terminals are tightened.