Transformer Terminal Lug Industry Knowledge Guide
1. Product Overview & Size Table Translation
Parallel Terminal T2 Purple Copper (Two-Hole & Four-Hole)
| Sequence | Code | Model | H | t | B | B4 | n2-Φd2 | B1 | B2 | b1 | n1-Φd1 | Md | D1 | B3 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 8TH.003.092 | 315A | 99 | 6 | 30 | - | 2-Φ10.5 | 33 | 63 | 30 | 2-Φ13 | M12×1.75 | 22 | 16 |
| 2 | 8TH.003.093 | 400A | 102 | 6 | 30 | - | 2-Φ10.5 | 38 | 64 | 30 | 2-Φ13 | M16×2 | 26 | 16 |
| 3 | 8TH.003.094 | 630A | 102 | 7 | 30 | - | 2-Φ10.5 | 38 | 64 | 30 | 2-Φ13 | M20×2.5 | 30 | 18 |
| 4 | 8TH.003.095 | 315A | 90 | 6 | 30 | - | 2-Φ10.5 | 50 | 50 | 25 | 4-Φ13 | M12×1.75 | 22 | 16 |
| 5 | 8TH.003.096 | 400A | 102 | 6 | 30 | - | 2-Φ10.5 | 60 | 60 | 30 | 4-Φ13 | M16×2 | 26 | 16 |
| 6 | 8TH.003.097 | 630A | 102 | 7 | 30 | - | 2-Φ10.5 | 60 | 60 | 30 | 4-Φ13 | M20×2.5 | 30 | 18 |
| 7 | 8TH.003.546 | 315A | 110 | 6 | 38 | 20 | 4-Φ9 | 33 | 63 | 30~35 | 2-Φ13 | M12×1.75 | 22 | 16 |
| 8 | 8TH.003.547 | 400A | 118 | 6 | 38 | 20 | 4-Φ9 | 38 | 68 | 30~35 | 2-Φ13 | M16×2 | 26 | 16 |
| 9 | 8TH.003.548 | 630A | 118 | 7 | 38 | 20 | 4-Φ9 | 38 | 68 | 30~35 | 2-Φ13 | M20×2.5 | 30 | 18 |
| 10 | 8TH.003.201 | 315A | 99 | 6 | 38 | 20 | 4-Φ9 | 50 | 50 | 25 | 4-Φ13 | M12×1.75 | 22 | 16 |
| 11 | 8TH.003.202 | 400A | 110 | 6 | 38 | 20 | 4-Φ9 | 60 | 60 | 30 | 4-Φ13 | M16×2 | 26 | 16 |
| 12 | 8TH.003.188 | 630A | 110 | 7 | 38 | 20 | 4-Φ9 | 60 | 60 | 30 | 4-Φ13 | M20×2.5 | 30 | 18 |
Dip Angle Terminal T2 Purple Copper (Two-Hole & Four-Hole)
| Sequence | Code | Model | H | t | B | B4 | n2-Φd2 | B1 | B2 | b1 | n1-Φd1 | Md | D1 | B3 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 8TH.003.083 | 315A | 90.5 | 6 | 30 | - | 2-Φ10.5 | 33 | 63 | 30 | 2-Φ13 | M12×1.75 | 22 | 16 |
| 2 | 8TH.003.084 | 400A | 93 | 6 | 30 | - | 2-Φ10.5 | 38 | 64 | 30 | 2-Φ13 | M16×2 | 26 | 16 |
| 3 | 8TH.003.085 | 630A | 93 | 7 | 30 | - | 2-Φ10.5 | 38 | 64 | 30 | 2-Φ13 | M20×2.5 | 30 | 18 |
| 4 | 8TH.003.086 | 315A | 83 | 6 | 30 | - | 2-Φ10.5 | 50 | 50 | 25 | 4-Φ13 | M12×1.75 | 22 | 16 |
| 5 | 8TH.003.087 | 400A | 97.5 | 6 | 30 | - | 2-Φ10.5 | 60 | 60 | 30 | 4-Φ13 | M16×2 | 26 | 16 |
| 6 | 8TH.003.088 | 630A | 97.5 | 7 | 30 | - | 2-Φ10.5 | 60 | 60 | 30 | 4-Φ13 | M20×2.5 | 30 | 18 |
| 7 | 8TH.003.184 | 315A | 101 | 6 | 38 | 20 | 4-Φ9 | 33 | 63 | 30~35 | 2-Φ13 | M12×1.75 | 22 | 16 |
| 8 | 8TH.003.203 | 400A | 108 | 6 | 38 | 20 | 4-Φ9 | 38 | 68 | 30~35 | 2-Φ13 | M16×2 | 26 | 16 |
| 9 | 8TH.003.185 | 630A | 108 | 7 | 38 | 20 | 4-Φ9 | 38 | 68 | 30~35 | 2-Φ13 | M20×2.5 | 30 | 18 |
| 10 | 8TH.003.428 | 315A | 92 | 6 | 38 | 20 | 4-Φ9 | 50 | 50 | 25 | 4-Φ13 | M12×1.75 | 22 | 16 |
| 11 | 8TH.003.531 | 400A | 104.5 | 6 | 38 | 20 | 4-Φ9 | 60 | 60 | 30 | 4-Φ13 | M16×2 | 26 | 16 |
| 12 | 8TH.003.429 | 630A | 104.5 | 7 | 38 | 20 | 4-Φ9 | 60 | 60 | 30 | 4-Φ13 | M20×2.5 | 30 | 18 |
Notes:
Model: Rated current capacity (315A / 400A / 630A)
H: Total height
t: Terminal thickness
B / B4: Width dimensions
n2-Φd2: Number & diameter of crimping holes
B1 / B2 / b1: Center-to-center distances between holes
n1-Φd1: Number & diameter of mounting holes
Md: Thread specification
D1 / B3: Connector dimensions
2. Function of Transformer Terminal Lugs
Transformer terminal lugs (also called cable lugs) are critical conductive connectors used to link transformer internal windings, busbars, and external cables/bushings. Their core functions include:
Reliable Electrical ConnectionThey create a secure, low-resistance joint between cables and copper bars, ensuring stable current transmission for the transformer's rated load.
Current Capacity MatchingAvailable in 315A, 400A, and 630A ratings to match different transformer capacities, preventing overheating or burnout due to insufficient current carrying capacity.
Mechanical & Vibration ResistanceMade of T2 purple copper, they offer high mechanical strength to withstand short-circuit electromagnetic forces and equipment vibration, maintaining stable contact.
Insulation & SafetyThe compact design and rounded edges reduce partial discharge risks. They also support insulation wrapping to prevent short circuits between phases.
Flexible Installation AdaptationParallel and dip-angle designs accommodate different transformer internal layouts, while two-hole/four-hole options enhance connection stability.
3. How to Install Transformer Terminal Lugs
Follow these steps for proper installation:
Preparation
Confirm the terminal model matches the rated current, cable cross-section, and mounting hole position.
Clean the surface of the terminal, copper bar, and cable to remove oil, dust, and oxidation.
Cable Crimping
Insert the stripped cable into the crimping end of the terminal.
Use a dedicated crimping tool to compress the terminal evenly to ensure tight contact between the cable and copper.
Positioning & Alignment
Align the terminal's mounting holes with the copper bar/bushing holes.
Use washers to distribute pressure and prevent surface damage.
Bolt Fastening
Tighten the bolts (M12/M16/M20) evenly in a crisscross pattern to the specified torque.
Avoid over-tightening, which can deform the terminal or copper bar.
Post-Installation Check
Verify the terminal is firmly secured with no looseness.
Apply anti-oxidation grease to the connection points if required, and wrap with insulation material.
4. Key Installation & Usage Notes
Torque Control: Always tighten bolts to the recommended torque value to avoid loose connections (which cause overheating) or terminal deformation.
Surface Protection: Ensure contact surfaces are clean and free of oxidation or foreign objects to maintain low resistance.
Correct Orientation: Use parallel terminals for linear connections and dip-angle terminals for angled layouts to avoid forced alignment.
Current Matching: Never use a terminal with a lower current rating than the transformer's design requirement.
Insulation Requirements: After installation, wrap the terminal with insulation paper or tape to prevent phase-to-phase or phase-to-ground short circuits.
Regular Inspection: Check for overheating signs (discoloration, burn marks) during maintenance, especially after heavy loads or short-circuit events.
5. FAQ
Q1: What material are these terminals made of?
A: They are made of high-quality T2 purple copper, which offers excellent conductivity, corrosion resistance, and mechanical strength.
Q2: What is the difference between parallel and dip-angle terminals?
A: Parallel terminals are for straight-line connections, while dip-angle terminals are designed for angled layouts, allowing installation without bending the cable or copper bar.
Q3: Why are two-hole and four-hole options available?
A: More mounting holes distribute pressure evenly, improving connection stability and preventing loosening under vibration or short-circuit forces.
Q4: Can these terminals be used outdoors?
A: Yes, but they should be protected with anti-oxidation treatment (such as tin plating) and covered with insulation or weatherproof materials.
Q5: How do I choose the right terminal for my transformer?
A: Confirm the transformer's rated current, cable cross-section, mounting hole position, and layout angle. Provide these details when ordering to get the correct model.