I am trying to understand how to treat the DC power port on my industrial device (read: will be used in CNC machine shops and industrial processing plants and the like) should be tested according to EN61000-6-2 for the surge test specified in EN 61000-4-5.
Table 3 in the standard calls out the tests required for DC power ports. Line 3.2 calls out 500V surge testing applied between line to ground and also between line to earth. So far there is nothing confusing.
However, note (c) is called out under "remarks" for surge testing, and it states that surge is not applicable under certain conditions. Most of the conditions don't apply to my situation, but the final line of the note states "DC Ports, which are not intended to be connected to a DC Distribution network, are treated as signal ports".
So now the question is - what is a DC Distribution network? My device is intended to run off of either 12 or 24 V DC power, but it's unclear to me if a voltage regulator on the same CNC machine or process equipment as my device is considered a "network", or if it must be some centralized regulator that is run throughout a plant, or some other definition. Can anyone here provide a working definition or clarity on what this means?
If I can treat the DC Power port as a signal port, it would greatly simplify my transient protection scheme.