Electrical connection

Most purpose-designed luminaires are stationary luminaires. One exception applies to free-standing and desktop luminaires, for which a flexible connection cable and a cable strain relief system are required according to HD 60364-5-559. Suspended luminaires are also considered stationary. It can be assumed that they feature a rigid electrical line. Cable strain relief is not required.

However, the connection terminals of suspended luminaires are usually suitable for accommodating flexible lines furnished with ferrules. The exception to this rule are continuous line systems with pre-wired trunking and plug connector systems, which usually do not feature flexible lines, even without ferrules. Generally, the installation instructions only depict the usual connection with a rigid electrical line. In such cases, consulting the luminaire manufacturer may be required.

The situation is similar when it comes to cable strain relief. Even though it is not actually required, many suspended luminaires feature a cable strain relief device for their electrical lines. Even recessed downlights often feature cable strain relief for supply and through-wiring even though it is not mandatory. Notes on this matter are contained in the installation instructions.

Beyond this, there are numerous plug connection systems for mains connection on the market. Thanks to pre-assembled electrical lines in an accordingly prepared installation, these luminaires can also be commissioned by unskilled persons (see e.g. figure).

Figure 2.31: Example for an electrical connection using plug connectors

Control lines for 1...10 V and DALI interfaces must be installed in a mains voltage-stable manner as a matter of principle. Both can be installed in a joint sheathed cable along with the mains cable. They each are based on low voltage, yet not on safety extra-low voltage (SELV). Lines for safety extra-low voltage must be passed separately as a matter of principle.

The specification of switches and safety measures (fault-current circuit breakers and circuit breakers) heavily depends on the type of control gear used for operating the connected luminaires (see chapter "LED luminaire operation, inrush current" and chapter "Discharge lamp luminaire operation, inrush current").

In some cases it may be possible to operate several LED luminaires at the secondary side of one control gear unit via serial connection. In such cases, it is important to ensure that the permissible operating current for the luminaires is met by the connected control gear unit. The maximum number or maximum overall capacity of the connected luminaires must not be exceeded. Constellations and possible pre-assembled connection cables verified by the manufacturer are documented in the luminaire's installation instructions (see also chapter "Control gear units for LED luminaires").