Battery Busbar Connectors: Bolt & Copper Bar Types, 120A-600A
Fixed busbar-to-cable connections for BESS, battery packs, and PCS terminals. Bolt type 100A-400A, copper bar type 200A-600A, rated up to 1500V DC.
What Is a Battery Busbar Connector?
A battery busbar connector is the fixed junction between a copper or aluminum busbar and a power cable in a battery system. Inside a battery pack or storage cabinet, the busbar collects current from the cells or modules, and the cable carries it to the next pack, the rack, or the inverter. The connector holds both sides together so the joint does not loosen under vibration, temperature cycling, or full-load current.
Where It Is Applied
You need one anywhere a cable lands on a busbar instead of going into a pluggable connector. The DC bus of a battery rack, the main bus of a storage cabinet, the terminal area of a PCS: these are the usual spots. The joint is meant to stay put, which lets it carry more current than a pluggable connector of the same size, and you can still unbolt it for service without cutting the cable.
Critical Reliability & Specs
The joint is the weak point in a battery system. A loose or undersized connection heats up, and heat at a DC junction speeds up contact oxidation. Our contacts are nickel-plated brass or T2Y pure copper, and the torque values are specified for every screw, so the connection stays where it was set.
Bolt Type vs Copper Bar Type: Which Battery Busbar Connector Do You Need?
The two series clamp the cable differently, and that engineering difference decides which one goes into your build. Review the technical baseline below to select the right specification.
Bolt Type Connector
Flexible panel-mount architecture for cable routing and bulkhead installations.
Copper Bar Connector
High-current busbar architecture for racks, cabinets, and power conversion systems.
| Parameters |
Bolt Connector
Flexible Panel-Mount Series
|
Copper Bar Connector
High-Current Rack & Cabinet Series
|
|---|---|---|
| Connection Method | Cable lug clamped by bolts onto the busbar | Copper bar clamps the cable contact against the busbar |
| Current Range | 100A to 400A | 200A to 600A |
| Rated Voltage | 600V / 1000V / 1500V DC | 1500V DC |
| Degree of Protection | Panel mount, PA66 housing | IP65 / UL94 V–0 |
| Typical Position | Panel or bulkhead mounted cable feed | Busbar termination in racks, cabinets, PCS |
| Cable Outlet | 360° rotatable | Fixed orientation |
Panel & Bulkhead Routing
Bolt Type Architecture
Bolt connectors handle most panel–fed cable runs. The cable lug bolts onto the busbar inside the housing, the housing mounts securely to the panel, and the outlet rotates 360° so the cable can exit in any direction. The range covers 100A to 400A in 600V, 1000V, and 1500V DC versions.
Heavy-Duty Power & Ingress Protection
Copper Bar Architecture
Copper bar connectors carry more current and seal better. A T2Y pure copper bar clamps the cable lug against the busbar, the housing is IP65 with UL94 V–0 flame retardance, and every model is rated 1500V DC. They top out at 600A, which puts them on the rack bus and the main cabinet bus rather than inside a module.
Bolt Connector Series: 120A / 250A / 400A
The bolt connector series features a single-core, panel-mount design. The housing is made of PA66, while the contacts use H59 brass with nickel plating. All three series use four M4 panel-mounting screws and feature a 360° rotatable cable outlet. CE recognized.
Product Specification Comparison
This product specification comparison table can be scrolled horizontally
on smaller screens. The first column remains visible while scrolling.
| Parameter | 120A Series | 250A Series | 400A Series |
|---|---|---|---|
| Rated current | |||
| Rated voltage | 600V DC | 1000V DC | 1500V DC |
| Material | PA66 / H59 brass with nickel plating | PA66 / H59 brass with nickel plating | PA66 / H59 brass with nickel plating |
| Applicable busbar | 15 × 3 mm | 20 × 4 mm | 25 × 6 mm (400A) |
| Dielectric strength | 2200V AC | 2200V AC | 4000V AC |
| Applicable cable lug | JG25–6 | JG50–6 / JG50–8 | JG120–10 (350A) |
| Mounting screws | M6 5.5 N·m / M4 2 N·m | M6 5.5 N·m / M8 12 N·m / M4 2 N·m | M8 12 N·m / M4 2.0 N·m |
| Applicable cables | 10 / 16 / 25 mm² | 35 / 50 mm² | 120 mm² |
| Cable outlet orientation | 360° rotatable | 360° rotatable | 360° rotatable |
| Mounting panel size | 20.0 ± 0.1 mm, Ø16.0 mm, 4 × M4 | 23.0 ± 0.1 mm, Ø18.5 mm, 4 × M4 | 27 ± 0.05 mm, Ø28.2 mm, 4 × M4 |
Specifications are presented for model comparison. Please confirm the final connector, busbar, cable lug, cable size, and tightening torque for your application before installation.
Copper Bar Connector Series: 250A / 350A / 600A
The copper bar connector series uses T2Y pure copper contacts with nickel plating in a PA66 housing. Insulation resistance is above 500 MΩ, contact resistance remains at or below 0.5 mΩ when measured at 100 mA, and the operating temperature range is −40°C to 125°C. Every model is rated for 1500V DC and features IP65 protection, a UL94 V-0 flame-retardant rating, and CE recognition.
Product Specification Comparison
This product specification comparison table can be scrolled horizontally
on smaller screens. The parameter column remains visible while scrolling.
| Parameter | 250A Series | 350A Series | 600A Series |
|---|---|---|---|
| Rated current | |||
| Rated voltage | 1500V DC | 1500V DC | 1500V DC |
| Material | PA66 / T2Y pure copper with nickel plating | PA66 / T2Y pure copper with nickel plating | PA66 / T2Y pure copper with nickel plating |
| Insulation resistance | >500 MΩ | >500 MΩ | >500 MΩ |
| Contact resistance | ≤0.5 mΩ (100 mA) | ≤0.5 mΩ (100 mA) | ≤0.5 mΩ (100 mA) |
| Dielectric strength | 4000V AC | 4000V AC | 4000V AC |
| Mounting screws | M8 12 N·m / M4 2 N·m | M10 23 N·m / M4 2 N·m | M10 23 N·m / M4 2 N·m |
| Degree of protection | IP65 UL94 V-0 | IP65 UL94 V-0 | IP65 UL94 V-0 |
| Applicable busbar | 20 × 4 mm | 25 × 6 mm | 30 × 8 mm (600A) |
| Applicable cable lug | JG50–8 / G70–10 | JG95–10 / JG120–10 | JG150–10 / SC185–10 |
| Applicable cables | 50 / 70 mm² | 95 / 120 mm² | 185 mm² (450A) |
| Operating temperature | −40°C to 125°C | −40°C to 125°C | −40°C to 125°C |
| Mounting panel size | 35 ± 0.1 mm, Ø23 mm | 45 ± 0.1 mm | 45 ± 0.1 mm, Ø33 mm |
600A Series: Verified compliance specification; standard tolerance: ISO 2768-m.
Specifications are presented for model comparison. Confirm the final connector, busbar, cable lug, cable size, and tightening torque for your application before installation.
GET THE RIGHT BATTERY BUSBAR CONNECTOR FOR YOUR SYSTEM
Send us your working current, DC bus voltage, busbar size, cable size, and panel opening. We will come back with the right model within a day, along with the datasheet and drawings.
Battery Busbar Connector Request
Send us your working current, DC bus voltage, busbar size, cable size, and panel opening. Our team will help you select the right battery busbar connector for your system.
24H Response
Technical Selection Support
Where to Use a Battery Busbar Connector
Commercial & Industrial Storage Infrastructure
Commercial and industrial BESS cabinets are the main home for battery busbar connectors. The cabinet’s main bus ties several battery racks to the PCS, and a 350A or 600A copper bar connector carries the rack–to–bus current. The IP65 seal matters here because storage cabinets see condensation and dust.
Battery Racks & Pack-Level DC Bus
Battery racks and packs use the 250A and 350A copper bar models on the rack-level DC bus. The joint stays tight through charge–discharge cycles, which is more than you can say for connections that rely on spring pressure alone.
PCS & Inverter Terminal Enclosures
PCS and inverter terminals usually land on a busbar inside the enclosure. A bolt connector brings the cable through the panel and bolts it to the terminal without welding, which keeps the inverter serviceable.
UPS Battery Rooms & String Isolation
UPS battery rooms are a quieter market but a steady one. Battery strings run long cables to the distribution, and bolt connectors at the string bus let you isolate one string without cutting anything.
EV Charging & Battery Swap Stations
EV charging and battery swap stations have the same busbar–to–cable joints as storage systems. The 600A copper bar connector covers the heaviest DC feeders.
How to Select the Right Battery Busbar Connector
Before you ask for a quote, run through these six checks. They line up with the spec tables above, and they apply to every connector in this range.
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Define the working current. Take the continuous current of the circuit and leave headroom for temperature rise. A circuit that runs 200A continuous belongs in the 250A copper bar range, not the 120A bolt series. The label rating is the ceiling; continuous duty sits below it.
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Match the voltage class. Bolt connectors come in 600V, 1000V, and 1500V DC. Copper bar connectors are all 1500V DC. Do not mix voltage classes on one string: if the bus is 1500V DC, use 1500V-rated parts end to end.
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Check the busbar size. The connector has to match what it clamps: 15 × 3 mm for the 120A bolt model, 20 × 4 mm for the 250A bolt and copper bar models, 25 × 6 mm for the 350A class, and 30 × 8 mm for the 600A model.
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Match the cable and lug. These connectors accept 10 to 25 mm² cable on the 120A bolt model, 35 to 50 mm² on the 250A bolt model, 50 to 70 mm² on the 250A copper bar model, 95 to 120 mm² on the 350A model, and up to 185 mm² on the 600A model. Pair the lug from the table with the cable your system already specifies.
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Consider the environment. A panel-fed cable run in a clean enclosure can use a bolt connector. A joint on an exposed busbar, or anywhere dust and moisture show up, should use an IP65 copper bar connector.
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Confirm the panel opening. The mounting panel sizes are 20.0, 23.0, 27.0, 35.0, and 45.0 mm depending on the model, with 4 × M4 mounting holes on every bolt connector. Confirm the panel thickness and opening tolerance before production, because the fit affects the seal.
Installation Notes and Torque Values
Get the torque right. The contact pressure of the joint comes from the screws, and so does the long-term resistance.
| Screw Size | Specified Torque |
|---|---|
| M4 | 2 N·m |
| M6 | 5.5 N·m |
| M8 | 12 N·m |
| M10 | 23 N·m |
Set the cable outlet before the final torque pass. The bolt connector outlet rotates 360°, so aim the cable first, then tighten to spec with a calibrated torque wrench. Leave the cable untwisted and do not exceed the specified torque limit.
