4.6.2. The integrated home system relays

In most integrated home systems, single-pole relays are used for controlling the consumers. In the existing arsenal of electrical symbols there is no symbol for a relay that can be used in a single-line diagram. There is of course a symbol for a relay, but for use in circuit diagrams. We will thus have to create a symbol ourselves.

In a traditional installation, the switch is used as a switching element. In an integrated home system, this switch is replaced by a relay. Analogous to a traditional installation we also draw in a switch, but surrounded by a square (general symbol for an electrical component). As a result, we stay close to the traditional method of drawing but we nevertheless indicate that it is not an ordinary switch.

Figure 29: We present our switching element of the integrated home system with the symbol for a switch, surrounded by a square.

In many integrated home systems the relays will not be separate components, but will belong together in a single housing of an output module. Such an output module can then be considered as an electrical component that also has to be shown on the drawing.

Figure 30: In the above figure the large rectangle indicates that all these relays are in the same output module.

Figure 31: Relay R24 (10A) drives contactor PR24 which in turn operates the power socket (20A).

The current that relay contacts can take is generally too low to operate more powerful consumers. In such a case we use the relay of the integrated home system to drive a more robust contactor. This second item then drives the connected consumer. The same method can be used for double-pole switching.