The flameproof switchgear type FCB is intended for use in workings of underground mines in non-hazardous or hazardous areas, classified as a, b or c level of methane explosion hazard and/or in workings classified as class A or B of coal dust explosion hazard.

It is designed for distribution of electricity in insulated “IT” networks 3×6 kV or 3×3, 3 kV or 3 kV.

The FCB switchgear is a fixed indoor switchgear system designed for both to be combined as multi-feeder switchgear and feeders intended for supplying individual isolated loads.

When combining feeders into multi-feeder switchgear, feeders placed side-by-side are connected with single-core flexible cables routed in metal sheaths. Customers may order the following switchgear versions:

  • Incoming feeder identified by the symbol FCB-6/630/2
  • Outgoing feeder (motor, cable, or transformer) identified by the symbol FCB-6/200/2.

The switchgear FCB is made up of four flameproof compartments:

  • cable(s) (rubber cable) connection compartment for the power supply;
  • disconnector and earth switch compartment;
  • main compartment equipped with switchgear, measuring, protection and control equipment;
  • connection compartment with cable(s) (rubber cables) supplying loads with power;

The main compartment equipment includes the following:

  • single-phase auxiliary transformer;
  • three current transformers;
  • one earth fault transformer (the so-called Ferranti transformer);
  • three three-coil voltage transformers;
  • self-powered protection unit designed to protect against the effects of phase-to-phase fault, line-to-earth fault and overloads in medium voltage networks;
  • vacuum circuit breaker;
  • three single-phase surge arresters;
  • separators for digital intrinsically safe and non-intrinsically safe control;
  • three control switches;
  • voltmeter;
  • microprocessor controller with a panel to visualising the feeder status capable of recording and viewing events.

The FCB-6/*/2 switchgear is designed for control:

  • local;
  • remote binary signals;
  • digital with visualisation from master dispatching system.

The method of controlling the switchboard is determined by the customer.

Ognioszczelna rozdzielnica typu FCB

Explosion protection

I M2(M1) Ex d [ia ib] I Mb
PB Exd[ia][ib]I

TC BY/112 02.01. 103,00152

Rated values

Ingress protection rating
Ambient temperature
-5°C ÷ 40°C

Maximum insulation voltage Um
7,2 kV

Rated voltage Un
6 kV or 3.3 kV or 3 kV

Rated current In
maximum 630 A depending on the current transformer

Rated short-circuit making capacity Iw
16 kA

Rated short-circuit breaking capacity Iu
40 kA

Rated short-circuit duration
1 second

Serial link type

approx. 2200 kg

Dimensions WxHxD [mm]


F C B 6 / * / 2
A 200 – execution as a drainage bay
630 – execution as a supply (inflow) field