Design Guide — Doc. 9292A Cresnet® Network • 23
External Power Supplies
ACresnet server supports cumulative wire runs up to 1,500ft (457m). However, due to voltage
loss over longer distances, the internal Cresnet power supply in the Cresnet server may not
provide enough power for longer wire runs.
In these scenarios, adding external power supplies (CNPWS-75 and C2N-SPWS300) ensure that
enough power is provided across longer wire runs. The Cresnet cable runs from the Cresnet
server to the power supply using only three of its four wires (Y data, Z data, and ground;
24VDCis not connected). Another Cresnet cable is run from the power supply to the Cresnet
client with all four wires connected.
NOTE:To determine the wire gauge required for a wiring run between power supply and
Cresnet client, only calculate the distance between the power supply and Cresnet client. The
wiring run between the Cresnet server and power supply is not included in this calculation.
For more information, refer to Resistance Equation Formula (on page21).
If a Cresnet network needs to be expanded beyond 1,500ft (457m), a Cresnet hub or
Ethernet-to-Cresnet bridge is required.