Dual Row Barrier Terminal Block – TB Series, 15A/25A/45A, 600V, 3–12 Positions

TB series dual-row barrier terminal blocks for electrical panel wiring, junction box connections, and power distribution applications. The barrier design separates adjacent terminals with insulating barriers, preventing accidental contact between adjacent conductors — essential for high-voltage and high-current applications where terminal-to-terminal shorts would cause equipment damage or fire. The dual-row configuration provides two independent connection points per position, allowing through-wiring (connecting two cables to the same circuit) or bridging between rows.

TB Series Model Reference

• TB1503: 15A, 600V, 3 positions. Wire range: 22–14AWG (0.5–2.5mm²)
• TB1504: 15A, 600V, 4 positions
• TB1506: 15A, 600V, 6 positions
• TB1508: 15A, 600V, 8 positions
• TB1512: 15A, 600V, 12 positions
• TB2503: 25A, 600V, 3 positions. Wire range: 18–12AWG (0.75–4mm²)
• TB2506: 25A, 600V, 6 positions
• TB2512: 25A, 600V, 12 positions
• TB4503: 45A, 600V, 3 positions. Wire range: 14–8AWG (2.5–10mm²)

Key Specifications

• Current Ratings: 15A, 25A, or 45A (model dependent)
• Voltage Rating: 600V
• Positions: 3, 4, 6, 8, or 12 (model dependent)
• Connection: Screw clamp (accepts solid and stranded wire)
• Housing Material: Nylon PA66, flame retardant UL94 V-0
• Mount: Panel mount (screw holes on base)
• Standard: UL 508, CSA C22.2

Barrier Terminal Block vs DIN Rail Terminal Block

• Barrier terminal block (this product): Panel-mount with screw holes on the base. Fixed position — screwed directly to the panel or enclosure floor. Lower cost. Preferred for fixed installations where the terminal block position does not need to change. Common in North American electrical panels and junction boxes.
• DIN rail terminal block (UK series): Clips onto 35mm DIN rail. Position can be changed by sliding along the rail. Higher cost. Preferred for European-style control panels and applications requiring flexible layout. Easier to add or remove terminals without drilling new holes.

Frequently Asked Questions

What wire gauge does each TB series accept?

TB15 series (15A): 22–14AWG (0.5–2.5mm²). TB25 series (25A): 18–12AWG (0.75–4mm²). TB45 series (45A): 14–8AWG (2.5–10mm²). Always use wire rated for the circuit current — do not use undersized wire even if it physically fits in the terminal. The terminal block’s current rating assumes the wire is also rated for the same current.

Can I use jumper bars to connect adjacent positions?

Yes. TB series terminal blocks accept standard jumper bars (bridge connectors) that link adjacent positions to the same potential. Jumper bars are available in 2–12 position configurations. Insert the jumper bar into the screw terminals of adjacent positions before tightening the screws. Jumper bars are useful for distributing a single supply to multiple circuits without running separate wires from the supply to each terminal.

Do I need wire ferrules with TB terminal blocks?

Recommended for stranded wire. Without ferrules, individual strands can escape the screw clamp area over time (especially with vibration), reducing contact area and increasing resistance. Use insulated wire ferrules (end sleeves) crimped onto stranded wire ends before insertion. Solid wire can be inserted directly without ferrules.

What is the torque specification for TB terminal block screws?

TB15 series: 0.5–0.6 N·m. TB25 series: 0.8–1.0 N·m. TB45 series: 1.2–1.5 N·m. Overtightening strips the screw head or cracks the terminal housing. Undertightening causes high resistance and potential arcing. Use a calibrated torque screwdriver for production installations.

Typical Applications

• Electrical panels: Power distribution connections in residential and commercial panels
• Junction boxes: Field wiring termination for sensors, actuators, and power circuits
• Motor control: Power and control wiring connections in motor starter panels
• HVAC: Control wiring connections in air handling units and rooftop equipment
• Industrial machinery: Power distribution within machine enclosures

Package Contents

TB series dual-row barrier terminal block (model as selected above). Mounting screws included.