Distribution blocks

Terminal blocks and distribution blocks are modular terminal blocks and junction blocks designed for the internal distribution of electrical panels. They allow a main outgoing circuit to be split into several secondary circuits, or grouped connections of power or control conductors to be made. Compliant with the IEC 60947-7 standard for terminal blocks, this equipment mounts on standardised DIN rail and uses silver-plated copper terminals to guarantee electrical continuity.

Functions and distribution principles of terminal and distribution blocks

Power distribution and conductor junction

Terminal and distribution blocks perform two complementary functions in an electrical panel. The first is to distribute a main outgoing circuit to several branch circuits using junction blocks and distribution combs. The second is to group several conductors at the same connection point to create equipotential bonding or phase distribution. Our installation experience confirms that this approach avoids branching directly on the terminals of circuit breakers or switch-disconnectors, preserving the integrity of the protective devices' connections.

DIN-rail mounting and panel integration

The polyamide housing of terminal and distribution blocks clips directly onto the DIN rail in line with the standardised dimensions of modular devices. This universal fixing principle speeds up wiring in the workshop or on site and allows later modifications without fully dismantling the panel. Our commissioning tests show that this modular mounting significantly reduces intervention time during installation extensions.

Technical characteristics and regulatory compliance

Materials and finishes of connection terminal blocks

Terminal and distribution blocks use a polyamide housing resistant to the thermal and mechanical stresses found in industrial environments. Silver-plated copper terminals ensure optimum electrical conductivity and limit oxidation of contact surfaces. This combination of materials guarantees the long-term electrical and mechanical performance of the connections.

Compliance with electrical safety standards

Connection terminal blocks meet the requirements of the IEC 60947-7 standard, which defines the construction and test rules for terminal blocks for power and control circuits. CE marking confirms compliance with the applicable European directives. We recommend systematically checking this compliance when choosing equipment for installations subject to the NF C 15-100 standard, as it determines whether the work is accepted by certification bodies.

Typical applications and installation choices

Internal distribution in industrial electrical panels

Terminal and distribution blocks are used in LV distribution panels, where they centralise main incoming supplies before distribution to protected outgoing circuits. Our installation feedback shows that their use is particularly relevant downstream of a switch-disconnector or a source-transfer switch, wherever the concentration of conductors requires structured connection organisation.

Grouped connection of control circuits

Control and signalling circuits often involve many small-section conductors that need to be connected at common points. Modular junction blocks allow this equipotential bonding to be carried out clearly and verifiably. Feedback from installers confirms that this organisation makes later troubleshooting easier and reduces wiring errors during commissioning.

Frequently asked questions

What is the difference between a distribution block and a simple junction terminal block?

A distribution block generally incorporates internal distribution combs that provide active electrical distribution to several circuits, whereas a junction terminal block mainly ensures continuity between conductors. Some modular models combine both functions depending on the wiring adopted.

Does the IEC 60947-7 standard apply to distribution combs?

The IEC 60947-7 standard specifically covers terminal blocks for power and control circuits, including their connection elements. Distribution combs associated with these terminal blocks must be sized in line with the terminal block's rated currents and meet the same thermal-withstand requirements.

Why choose silver-plated copper for distribution terminals?

Silver-plated copper offers low electrical resistivity and increased resistance to oxidation compared with bare copper. This finish preserves electrical contact quality over time, particularly in environments where electrical panels experience temperature variations or a polluted atmosphere.

Is DIN-rail mounting for terminal and distribution blocks compatible with all modular devices?

DIN rail to EN 60715 is a universal standard for low-voltage modular devices. Terminal and distribution blocks designed for this profile integrate naturally into panels fitted with circuit breakers, relays or other electrical measurement and control devices on the same support.