C7-30A DC Contactor

Product Profile

The BSB C7-30A DC contactor is a compact, epoxy-sealed DC contactor engineered for low-current applications in electric vehicles, charging systems, and photovoltaic equipment. With a 30A continuous current rating and excellent sealing performance, this contactor is ideal for safe and reliable switching in harsh environments. It features a non-polarity design, RoHS-compliant materials, and international certifications including UL, CE, and TUV.

Product Features

• Fully Sealed Construction: Epoxy resin encapsulation protects internal components from oxidation, dust, and moisture.

• High Voltage Capability: Supports up to 1000VDC operating voltage, suitable for EV and solar energy applications.

• Non-Polarity Design: Simplifies installation with no directional constraints for both coil and main contacts.

• Energy-Saving Option: Built-in economizer reduces holding power to just 1.6W.

• Wide Temperature Range: Operational from -40°C to +85°C with IP67-rated enclosure.

• Certifications: UL, CE, and TUV approved for global reliability and compliance.

Typical Applications

• Pre-charge relay for electric vehicles (EVs)

• DC contactor for small-scale energy storage systems (ESS)

• Auxiliary contactor in photovoltaic inverters

• Charging station subcircuits

• Robotics and AGV power control

Summary of Technical Parameters

Dimensional Drawing & Wiring Diagram

Vertical type without economizer

Horizontal type without economizer

Vertical type with economizer

FAQs About The BSBC7-30A DC Contactor

Q1: Can the C7-30A dc contactor be used for pre-charge applications?
A1: Yes, it’s suitable for pre-charge circuits, especially due to its reliable switching at low current levels.

Q2: Does the C7-30A dc contactor support reverse surge protection?
A2: Only products equipped with a PWM economizer include a surge suppression circuit. If you choose a standard product without an economizer, you need to address the issue of counter-electromotive force (back EMF) from a design perspective.

Q3: Does the C7-30A dc contactor support auxiliary contacts?
A3: Yes. It is recommended to refer to the C7-30A DC contactor specification and choose the optional configuration with either normally open or normally closed auxiliary contacts.

Q4: Looking for a more compact 30A pre-charge contactor from the C7-30?
A4: Yes. For pre-charge applications, the C7 series does include a more compact 30A contactor with UL certification (compared to this model). To avoid confusion with the standard C7-30 product, it will be sold under a special product code. If you’re looking for a smaller-sized C7 series contactor that is not listed on the website, please contact the BSB sales team and mention that you need “the most compact C7-30 contactor.”

Q5: Besides the C7 series, what other DC contactors are available?
A5: In addition to the epoxy-sealed DC contactors of the C7 series, BSB also offers DC contactors with other sealing types. Please refer to the full DC contactors category section on the official website or contact the BSB sales team for more information.

Precautions for Use

Please follow the precautions below to ensure reliable and safe operation of the C7-30A high voltage DC contactor:

Mechanical Installation

• Always use spring washers to prevent screws from loosening during installation.

• The recommended tightening torque for screws is 3–4 N·m. Exceeding this value may damage the casing.

• Do not use the contactor if it has been dropped or subjected to impact.

Wiring and Polarity

• Both the main contacts and coil leads are non-polarized, allowing flexible wiring.

• Ensure that the external wiring terminal is in reliable contact with the contactor’s main terminal.

• Avoid getting grease or debris on the terminal surface, which may cause abnormal heating.

Surge Suppression

• For models with economizer, a built-in reverse surge absorption circuit is included—no external protection is needed.

• For models without economizer, it is recommended to install a varistor or TVS diode at the coil terminals (1.5–2× rated coil voltage).
  ⚠️ Do not use diodes, as they may reduce the contactor’s breaking capacity.

Environmental Conditions

• Operating temperature: -40°C to +85°C
  The contactor’s internal chamber is gas-filled, and elevated temperatures accelerate gas diffusion. Avoid exceeding the specified temperature range.

• Do not install the contactor near strong magnetic fields (e.g., transformers, magnets) or heat-emitting components (e.g., fuses, shunts).

  • If placement near a heat source is unavoidable, perform a temperature rise test to verify safety.

• Altitude limit: ≤4000m

• IP rating: IP67 (inner space sealed)

Switching and Load Conditions

• Do not exceed the rated switching capacity and life expectancy.
  The contactor is a high-voltage DC switch; once it reaches end-of-life, its disconnect function may degrade.

• Design your circuit logic to cut off the power within 1 second in the event of contactor failure.

• For inductive loads (L/R > 1 ms), a surge protection device (e.g., TVS or varistor) should be connected in parallel.

• For resistive loads, apply the rated current directly; for capacitive loads, a pre-charge circuit must be used.

  • If not, inrush current may cause contact welding.

Coil Operating Notes

• If the contactor is opened and closed repeatedly at full load and rated voltage, the coil temperature may rise, increasing resistance and pick-up voltage.

• In such cases, take one of the following measures:

  • Reduce the load current

  • Limit the on-time

  • Use a slightly higher-than-rated coil voltage

• For energy-saving models, after power is applied, the economizer activates 0.1s later.
  Do not cycle the contactor at this exact moment to avoid coil damage.

• Ensure that the drive circuit voltage and power are sufficient for the coil’s inrush and holding requirements; otherwise, breaking ability may be reduced.

Others

• 🔙 Back to C7 Series DC Contactors

• 📄 Download the C7-30A Specification PDF

• 📚 Learn more about DC Contactors & Relays