Low voltage grounding resistor

The LIMITER MC4 is a traditional grounding resistor: it limits the first fault to earth in B.T. systems. (≤ 10 A) using high ohmic value resistors. This eliminates arcing and allows continuous operation for industrial installations.


Use of the limiter

Impedance use has been the most used way to ground neutral in low voltage systems in recent decades, as it provides better operational performance and a higher degree of safety.

In this scenario the LIMITER MC4, with its high value resistances, is ideal for landing the neutral of generators and transformers.

Parameters Available in the Display

  • Measurement and indication of neutral-earth voltage;
  • Measurement and indication of ground fault current;
  • Search for the location of the fault by means of a cyclic current actuated through a start-stop button;
  • Online supervision of the integrity of neutral-resistor-ground connections.

Operational Features

  • Local LED signalling of normal operation of the electrical system, i.e. without the presence of a fault to earth;
  • Local LED signalling when a fault occurs to earth;
  • Possibility of searching the place where the fault occurred;
  • Online monitoring of the integrity of the circuit section between neutral-resistors and ground limitation resistors, signaling the condition to normal or not (absence or not of this integrity).

Electrical Features

  • Phase-neutral voltage of the electrical system: 480/ 3V(*)
  • Insulation voltage class: 0.6kV
  • Limiting current: SA and pulse 4A for research (*)
  • Nominal frequency: 60Hz;
  • Aux. supply ranges available: 85-265 VAC or 100-230 VDC;
  • Auxiliary NAF contacts indicating remotely: Phase-earth
    Absence of neutral resistor-ground circuit integrity;
    Absence of auxiliary supply voltage
  • Phase to ground current limiting resistors mounted on ceramic insulators.

(*) Other figures on request

Constructive Features

  • Housing made of 14USG sheet steel and 12USG structure (resistor compartment IP-21 and supervisory compartment IP-40)(*);
  • Fixation on vertical surface;
  • Wiring in the resistor compartment compatible with temperature rise during earth faults;
  • Light grey electrostatic paint, MUNSELL N6.5 (*);
  • Approximate approximate dimensions: 900x550x350 (HxWxD) mm;
  • Approximate weight: 50kG;
  • Device for placing the padlock in the supervisory compartment door (security NR-10)
  • Sheltered installation (*)

(*) Other figures on request

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