Products > ZERO Hertz


The ZERO-Hertz® trip unit is a solid state overcurrent device for use on one and two pole DC circuit breakers in voltage classes up to 1,000 volts. The ZERO-Hertz® comes standard with long-time, short-time, instantaneous, ground fault, and reverse current. All of the protective features except long time can be turned off to allow for greater coordination and flexibility of use. 

ZER0-Hertz DC trip unit Programming of the ZERO-Hertz® is done using the buttons and 16 character backlight LCD display on the front of the unit. All settings are made in amps and seconds and an integrated security key prevents accidental modification of settings. The LCD displays the current during normal operation and shows the phase currents and type of trip after an event. The number and type of trip events along with the commissioning data are accessible at any time from the front panel. This data can also be cleared or modified at anytime from the front panel. The ZERO-Hertz® also has a "SELF TEST OK" led that verifies the unit is functioning properly. There is also a "PICK-UP" LED that indicates when the current reaches or exceeds the long-time pick up value.

ZERO-Hertz® FeaturesZERO-Hertz installed on a DB-25 Breaker

True RMS sensing

DC and AC power input available

50mV or 100mV DC metering shunts
(customer supplied) can be used

Hi-Range and Low-Range transducers available

User configurable alarm relays available

Trip unit with transducers can be calibrated using a high current AC test set (on most breakers)

RS485 communications port with ModBus protocol

Secondary test set available

Retrofit Kits available for multiple breaker types.

ISO 9001

Product Information

Data Sheets

ZERO-Hertz® Product Flier

Instruction Manuals

ZERO-Hertz® with QT Instruction Manual