Cabur control terminal boards have been developed in order to enable electric power suppliers and users to easily check measuring instruments, without interrupting the current carrying circuits during the verification itself or during the replacement of the instruments.

Each terminal board is composed by an insulating body, carrying the copper zinc alloy terminals to which the ammeter, voltmeter circuits and the devices for disconnect and short circuit operations are connected. Each terminal board is supplied with a transparent cover (of cellulose acetate), provided with appropriate captive screws for the sealing of the assembly.

In two-phase and three-phase terminal boards, the insulating base is built from Kelon (an abbreviation of Keramic + Nylon): this is a nylon 6 based, self-extinguishing UL94V-0 polymer with the addition of special ceramic spheres and subsequent thermal stability. The inclusion of the microspheres and the thermal procedure make the item extremely hardwearing (rigid, but also able to withstand impacts and wear and tear)

The current phases are marked in different colours, to be defined when ordering.

The use of MCM series control terminal boards allows:

1. disconnection, upstream and downstream the measuring instruments
2. the insertion of a test instrument, downstream or upstream the measuring
   instruments
3.  shunting, by means of common plugs, from the four connection terminal
4.  voltage transmission from the beginning of the ammeter circuit to the
   disconnect slide-link by means of a simple cross connections.

In normal service, voltmeter leads are connected to the R-S-T terminals, whilst the ammeter leads, are to be inserted in the terminals identified R1‑R2, S1-S2,
T1‑T2. The instruments are connected to terminals 1 and 2. The vertical slide‑link cross connections are closed, the horizontal slide-link
cross connections are open.

When inserting control instruments, the following instructions are to be followed:
- by means of normal plugs, the voltmeter leads must be shunted from the
test instrument on to the voltage sockets of the disconnect slide-link or to the
insertion blocks of the fuse-holders;
- the ammeter leads of the test instruments must be inserted in sockets 1 ad
R1 or 2 ad R2; same procedure is to be followed for the other phases;
- therefore, the corresponding vertical slide-link must be disconnected.

If there is a need to replace a measuring instrument, it is necessary to
previously close the horizontal slide-links, disconnect the vertical slide-links and
open the slide-link.

Feeding conductors (incoming and outcoming) are inserted from the rear of the
terminal board, with conductors passing through slots on the insulating base of
the terminal board