MAJ K4140

SKU: MAJ K4140

BRAND: Major Tech

Digital IP54 Earth Loop Impedance Tester with Anti-Trip Technology and Dual display that allows simultaneous measurements


 The K4140 incorporates Anti-Trip Technology (ATT) which electronically bypasses RCDs when performing loop impedance tests. This saves time and money by not having to take the RCD out of the circuit when testing and is a safer procedure to follow. With the ATT function enabled, a test current of 15mA or less is applied between Line & Earth. It enables resolution loop impedance measurements (up to 0.01 ohm), without tripping RCDs rated at 30mA and above. A full set of new safety test leads are included, they have an overmould for maximum grip and are extremely robust. The instrument also comes in a soft carry case, a quick reference guide locates on the instrument body, a soft strap belt and is supplied with a calibration certificate.



  • Phase Rotation
  • Anti-Trip Technology for complete trip free Loop testing on all RCD's rated 30mA and above
  • Dual display allows simultaneous measurements like Loop & PFC/PSC.
  • Two wire connections for Loop L-L, L-N and PSC testing is possible.
  • Phase rotation, voltage and frequency measurements.
  • Lock-down test button for “hands free” testing with auto-start operation.
  • Display and front panel keyboards with backlight to be visible in dark places.
  • Water and dustproof (IP54).



Rated voltage
  • L-PE ATT OFF : 230V (50/60Hz)
  • L-N : 230V (50/60Hz)
  • L-L : 400V (50/60Hz)
Operating Voltage
  • L-PE ATT OFF : 100~280V (45~65Hz)
  • L-N/L-L 100~500V (45~65Hz)
Range (Auto-Ranging)
  • L-PE ATT OFF : 20/200/2000Ω
  • L-N/L-L : 20Ω
Nominal Test Current at 0W External Loop: Magnitude/Duration at 230V
  • 20Ω :6A/40ms L-PE ATT OFF
  • 200Ω :2A/20ms L-PE ATT OFF, 20W:6A/20ms (L-N/L-L)
  • 2000Ω :15mA/500ms L-PE ATT OFF
  • L-PE ATT OFF : ±3%rdg±4dgt
  • L-N : ±3%rdg±4dgt
  • L-L : ±3%rdg±8dgt

PFC(L-PE)/PSC(L-N/L-L) (2)

  • Function : 230V (50/60Hz), L-N : 230V (50/60Hz)
  • Rated voltage : L-L: 400V (50/60Hz)
  • 100~280V (45~65Hz), 100~500V(45~65Hz)
  • Operating Voltage
    • 2000A/20kA (L-PE ATT OFF)
    • 2000A/20kA (L-N/L-L)
  • Range (Auto Ranging) : 20Ω :6A/40ms
  • Nominal Test Current at 0W External Loop
    • 20W : 6A/20ms
    • 200Ω : 2A/20ms
  • Magnitude/Duration at 230V : 2000 :15mA/500ms

Phase Rotation

  • Operating Voltage : 50~500V, 45~65Hz
  • Remarks
    • Correct phase sequence : displayed "1.2.3" and mark
    • Reversed phase sequence : displayed "3.2.1" and mark


  • Measuring range : 0~500V, 45~65Hz
  • Accuracy : ±2%rdg±4dgt(L-PE ATT OFF), ±0.5%rdg±2dgt(L-N/L-L)


Datasheet Download

D2781450368.pdf" target="_blank" title="PDF Datasheet" rel="noopener noreferrer">Manual Download