Hello,
According to the IEEE std 802.3-2002 section two, the electrical separation shall withstand the following electrical strengt test:
- 1500Vrms at 50-60Hz for 60sec, applied as specified in IEC60850.
What is the foundation of this safety requirement? - insulation: reinforced? - definition of ethernet; SELV or TNV??
If ethernet is used between two SELV circuits, does the requirement of the high electric strength test voltage still apply?
Please help, kind regards
Menno van Rooij
First of all, the specification is IEC 60950 (in case you were trying to find it in 60850).
The specification ensures that a fault within the Ethernet device (computer, repeater, bridge, etc.) does not propagate to other devices connected through the network. Essentially, it is a requirement on the coupling transformers used to connect to the communications medium.
-- Rich Seifert Networks and Communications Consulting 21885 Bear Creek Way (408) 395-5700 Los Gatos, CA 95033 (408) 395-1966 FAX
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In most cases, it is the breakdown voltage on the transformers.
It does need to be transformer isolated as it often operates between stations with different grounding points.
I still haven't gotten around to testing UTP ethernet with a large AC common mode voltage on the cable, just to see if it really works. Probably 240V would be enough for me.
-- glen
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