In the event of a lightning or grounding accident, an instantaneous voltage drop occurs in
the accidential phase. The capacitance of the components in the other two healthy phases
is due to the instantaneous voltage rise and the capacitance rise between phase line and
ground too, and then the leakage current is raised instantaneously, and circuit breakers installed
on a sound lines are momentarily tripped. The phenomenon is occurring, and this unnecessary
operation has been misunderstood for surge voltage.
In the event of a lightning strike on the power distribution line, a phase 1 grounding
occurs through an arrestor.
① In the ELCB installed on the sound phase, the Capacitance and Voltage between the
ground and line, increase 1.73 times or more.
② Capacitive leakage current (IGC) rising (Application formula : IGC = 2 × π × f × C × V )
③ Normal type ELCB will be instantaneously tripped by this formula.
④ In this case, most of the instantaneous leakage current event time is generated
within the system protection time of 100 msec.
⑤ This condition is called unnecessary operation and an IOP ELCB of time delay type
which delays operation time is required to prevent this case.
Most of the general earth leakage breaker is an instantaneous trip, but the IOP earth leakage breaker is an operation delay type trip.
Inconvenience Operating Prevent means a single-phase, high-sensitivity earth leakage breaker.
Single-phase OP earth leakage breaker specifications
Comparison of operating characteristics with general earth leakage breaker
Installation method for protection cooperation of Category A and B earth leakage breaker
Installation method explanation
Installation method explanation
-General type earth leakage breaker should be installed at the bottom, and delayed operation (IOP) type earth leakage breaker should be installed at the top or
Can be freely installed at the bottom.
-Install a delayed operation (IOP) type earth leakage breaker at the top and install an instant trip (general) type at the bottom in combination.
In this case, protective coordination operation is possible, so in case of an instantaneous short circuit at the bottom, the lower instantaneous trip
Only the (general) type circuit breaker trips, and the upper delay operation (IOP) type earth leakage breaker must not fall at the same time.
Problems of 3-Phase General ELCB (instantaneous trip) Type
- Industrial three-phase ELCBs are sometimes tripped, so they avoid using them, and
installing MCCB instead of ELCB, they install and operate them as leakage alarms
on the upper switchboard, making it difficult to prevent fire.
- If it is applied to the refrigerator and freezer and occasionally tripped, the compressor
motor overheats and fires occur due to ELCBs while using MCCBs due to concerns
over damage to the food in refrigerator.
- When installing and operating general type ELCB, it has a problem of unnecessary
operation due to the occurrence of instantaneous leakage current when operating
(M/C)magnet contactor at the load side. Most ELCBs use instantaneous trip type which
inevitably leads to unnecessary operation.
- Fires frequently occur due to overheating of the three-phase air cooler motor.
(when installing a MCCB)
- Due to the instantaneous trip operation, it is not suitable to use as general ELCBs for motor
protection, so it is being replaced with MCCBs.
Korea Patented Technology and Operational Characteristics
- The present three-phase short circuit breaker is a medium-sensitivity ELCB that trips with a
leakage current of 100mA to 1,000mA within 0.1sec. This patent application product designs
a trip delay type three-phase ELCB by applying a time sequential comparison algorithm when
an instantaneous leakage current occurs.
- If a leakage current exceeding 0.1 second occurs, it can be recognized as a short circuit and
trip normally to prevent electrical leakage fire, so that the production equipment can install
and operate ELCB sufficiently.
- Motor protection 3-phase ELCBs
- 3-phase ELCB for semiconductor and
- 3-phase ELCB inside factory production equipments
- Large refrigerator, freezer, air conditioner motor
- For compression compressors
- Electric vehicle chargers
- 3 phase inverter fountain pumps
- For elevators and escalators
- Injection machines
- For fans of 3-phase air conditioner
-Protection cooperation with single-phase earth leakage breaker is possible by operating time (other products cooperate with protection by leakage current size)
-When installed in industrial production equipment, it is possible to prevent electric leakage (operable at 100mA class)
-Prevention of electric shock to certain parts of semiconductor and display production equipment
- Significantly reduce the installation cost of the leak detector by installing the existing MCCB and external leak detector simultaneously with one 3-phase earth leakage breaker
(Satisfies Article 41, Paragraphs 1, 2, and 3 of the Technical Standards for Electrical Equipment)
-Criteria for installing a leak detector: Satisfies Article 41 (4)