Electromagnetic Compatibility (EMC) Recommendations

A star 24 Vdc distribution is preferable to a serial 24 Vdc distribution because star 24 Vdc distribution can minimize the wiring impedance.

If serial distribution is used, it is advisable to wire two serial loopback wires (see the two blue wires in the following drawing) in order to minimize impedance.

In a poor-quality electrical distribution network, it is advisable to use a power supply compliant with OVC II and which can withstand up to 500 Vac incoming and also offers galvanic insulation between the power supply AC input and the power supply DC output of 4 kVac at 50 Hz.

It is advisable to comply with the segregation rules between low level signals (24 Vdc) and power conductors, see:

www.electrical-installation.org see the ElectroMagnetic Compatibility (EMC) part, Wiring recommendations section (information only available in English).
EIGED306001EN Electrical Installation Guide