C303 – 1-pole bi-directional DC NO contactors up to 350 amps

Compact 1-pole NO contactors for DC up to 1,500 volts rated insulation voltage, continuous currents up to 350 amps and high making and short-time currents.

C303 1-pole bi-directional DC NO contactors,
Ue up to 1.000 volts, Ith up to 350 amps,
Design with external PWM control
C303 1-pole bi-directional DC NO contactors,
Ue up to 1.000 volts, Ith up to 350 amps,
Design with economical high-efficiency drive

The C303 bi-directional DC contactors are compact, high-performance switchgear for applications with high making currents or large capacities. All versions can carry up to 350 amps continuously; in the event of a short circuit, significantly higher currents can flow without the contacts welding together. This means that the contactor retains its full function to disconnect high loads – up to 1.5 MW – regardless of the current direction. This full bi-directionality is important for systems with a charging and discharging process.
Typical applications are DC circuits in inverters, in battery storage systems or in charging stations in the e-mobility sector.


Compact dimensions – High rated insulation voltage Ui up to 1,500 volts

Small dimensions – great performance! Nevertheless, all the air gaps in the contact area have been generously dimensioned. The rated insulation voltage is 1,500 volts.
The arc chamber of the C303 is made of plastic. This is efficient and saves weight.

High continuous thermal current Ith up to 350 amps

All versions of the C303 can permanently carry up to 350 amps – provided a sufficiently dimensioned connection cross-section of 150 mm². The maximum ambient temperature for industrial applications is 80 °C. These excellent values are achieved through very high contact forces.

3 versions available for different applications

The C303 is available with coil control and an energy-saving PWM module, with an economical high-efficiency drive or in a special version as a pre-charging contactor.

Full bidirectionality – reliable disconnection of high performances

All versions of the C303 can reliably separate high currents and voltages when required, regardless of the direction of the current. These properties are achieved by the special arrangement of blowout magnets and arc chamber, burn-off resistant silver contacts, high contact forces and generously dimensioned air gaps in the contact area.

Auxiliary switch with mirror contact function

The C303 contactors have an auxiliary contact with mirror contact function according to IEC 60947-4-1, annex F. Mirror contacts are required in feedback circuits of safety controls. The mirror contact function informs about the switching state and ensures that the NC contact of the auxiliary contact is not closed at the same time as the NO main contact.


The compact switching device can be integrated especially in areas where there is no space for larger series. Since the C303 series can reliably switch in both directions of current, it is ideally suited for applications with energy recovery. Here, the C303 reliably ensures the galvanic isolation of both poles of the battery from the vehicle’s powertrain in the event of a fault. Areas of application for the C303 series are regenerative systems and DC charging stations or battery test benches. A further application for the use of bi-directional contactors of the C303 series are stationary energy storages. Batteries are charged and discharged regularly. For this purpose it is important that the contactors can switch off safely in both current directions.


Type of voltageDC bi-directional
Main contacts, configuration1 NO
Rated operating voltage Ue1,000 V
Rated insulation voltage Ui1,500 V
Rated impulse withstand voltage Uimp8 kV
Pollution degree
Overvoltage category
Conv. thermal current Ith350 A
Aux. contact1x SPDT max. with mirror contact function, single-break
Snap-action switch S880: AC-15: 230 VAC/1.0 A; DC-13: 60 VDC/0.5 A
Control voltage Us Version I: 24 V DC, operating range 9 ... 32 V DC, PWM module (integrated9
Version E: 24 V DC, operating range 20.4 ... 27.6 V DC, high-efficiency drive
VibrationISO 16750-3: upon request
ShockISO 16750-3: upon request
Mounting orientationhorizontal, vertical
Temperature range–40° C ... +85° C
Mechanical endurance200,000 operations
Show all data

Related Downloads

Flyer C303
C303 contactors – 1 pole bi-directional DC NO contactors up to 350 amps
Safety instructions contactors
AFS / C100 / C110B / C130 / C137 / C152...C159 / C160 / C162 / C163 / C164 / C165 / C193 / C195 / C294 / C295 / C160 / C3xx / C8xx / C400 / C600 / CA / CF / CH / CL / CP / CPP / CS / CT / CU / S100/80 / S132 / S134 / S135 / S005 / S007 / S008 / S306 / S307 / S310
Hannover Messe 2024
Discover the C303 contactor and the latest DC innovations from Eddicy and experience an exciting lecture program from April 22-26 at our booth C40 in Hall 11.
Learn more
/en/products/contactors/c303/thank-you/C303 – DC bi-directional switchingContactors

Your quick contact to us!

If you have any questions, suggestions or other concerns, please let us know. Please fill out our short contact form.