ZyXEL Communications PLA-470 V2 - V3.0.5 Installationsanleitung PDF herunterladen (Seite 182)

propagates over the cables then goes via the circuit breaker panel to start at the vari-

ous cables again. The wiring length can exceed 300m, which is considered as the

acceptable limit for a satisfactory useful throughput.

The electrical devices connected to the network are potential sources of electro-

magnetic disturbances for the PLC signal. Remember that the average length of the

electrical wiring between the switchboard and the farthest outlet should not exceed

200m.

Three-Phase Wiring

Buildings, large houses, professional premises, or plants have greater electrical

power requirements than a domestic dwelling; therefore, the electrical network is

often a three-phase network in them.

Four cables (neutral, phases 1, 2, and 3) start from the circuit breaker panel and

supply the outlets of the building. Figure 8.11 illustrates an example of three- phase

wiring in a building with several stories with the various electrical phases supplying

the building stories. Two cables starting from the switchboard travel all over each

story: a phase cable and the neutral cable.

The single cable that is common to the entire building is the neutral cable. The

other cables are electrically dissociated. It is important to remember that the PLC

signal flowing in one of the cables (neutral or phase cable) can be transmitted in the

other cables due to an induction phenomenon. This makes it possible to build the

topology of the PLC local area network by making optimal use of the properties of

the electrical wirings.

Topology of Electrical Networks 163

Figure 8.11 Topology of a three-phase electrical network for a large building

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ZyXEL Communications PLA-470 V2 - V3.0.5 Installationsanleitung Seite 182