Single-phase current relay, window type

These single-phase current relays monitor over- and undercurrents. Manual resetting and automatic resetting are supported by one relay. The start-up lock and operating time can be set separately. The relay warning status is easily monitored with the LED indicator.
  • Single-phase current window relay
  • In 22.5 mm wide industrial housing
  • Under and over control
  • Supply voltages: 24 VAC/DC, 100 to 240 VAC
  • Easy wiring with ferrules
Specifications & ordering info

Ordering information

Measuring current

Supply voltage

Order code

2 to 20 mA AC/DC,
10 to 100 mA AC/DC,
50 to 500 mA AC/DC



100 to 240 VAC

K8AK-AW1 100-240 VAC

0.1 to 1 A AC/DC,
0.5 to 5 A AC/DC



100 to 240 VAC

K8AK-AW2 100-240 VAC

10 to 100 A AC,
20 to 200 A AC



100 to 240 VAC

K8AK-AW3 100-240 VAC


Current transformer

Input range

Applicable relay

Order code


10 to 100 A AC, 20 to 200 A AC



Note: The K8AK-AW3 is designed to be used in combination with the K8AC-CT200L (direct input not possible)


Ambient operating temperature

-20 to 60°C (with no condensation or icing)

Storage temperature

-25 to 65°C (with no condensation or icing)

Operating voltage range

85% to 110% of rated operating voltage

Rated power supply frequency

50/60 Hz±5 Hz (AC power supply)

Output relays
(1 × SPDT, normally closed operation)

Resistive load

5 A at 250 VAC or at 30 VDC

Maximum contact voltage

250 VAC or 30 VDC

Maximum contact current

5 A

Maximum switching capacity

1,250 VA, 150 W

Mechanical life

10,000,000 operations

Electrical life

50,000 operations at 5 A, 250 VAC or 30 VDC

Degree of protection

Terminal section: IP20

Case material

PC and ABS


Approx. 150 g

Operating power

Isolated power supply

2.0 VA/1.1 W max. at 24 VAC/DC, 4.6 VA max. at 100 to 240 VAC

Operate (SV)

Operating value setting range

10% to 100% of maximum measuring current

Operating value

100% operation at set value

Reset (HYS.)


5% of operating value (fixed)

Resetting method

Manual reset/automatic reset (switchable)
Manual reset: Turn OFF operating power for 1 s or longer

Operating time (T)

0.1 to 30 s

Operating power ON lock (LOCK)

0 to 30 s (The startup lock timer starts when the input has reached approximately 30% or more of the set value.)

Note: Enabled only for overcurrent operation

Repeat error

Operating value

±0.5% full scale (at 25°C and 65% humidity, rated power supply voltage, DC or 50/60 Hz sine wave input)

Operating time

±50 ms (at 25°C and 65% humidity, rated power supply voltage)

Input frequency range


DC input or AC input (45 to 65 Hz)


AC input (45 to 65 Hz)

Overload capacity


Continuous input at 120% of maximum input, 1 s at 150%


Continuous input at 120%, 30 s at 200%, and 1 s at 600% with an OMRON CT (K8AC-CT200L)


Power (PWR): Green LED, relay output (RY): Yellow LED, alarm outputs (ALM): Red LED

Applicable standards

Conforming standards

EN 60947-5-1
Installation environment (pollution level 2, installation category III)


EN 60947-5-1

Safety standards

UL 508 (Recognition), Korean Radio Waves Act (Act 10564), CSA and CCC

Size in mm (H × W × D)

90 × 22.5 × 100

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