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Safety insulation requirement ethernet

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Anonymous
July 20, 2004 4:40:14 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

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
Anonymous
July 20, 2004 1:09:56 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <942e5c78.0407192340.70fc1707@posting.google.com>,
mvr@prodrive.nl (Menno van Rooij) wrote:

> 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.

First of all, the specification is IEC 60950 (in case you were trying to
find it in 60850).

>
> 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?
>

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

Send replies to: usenet at richseifert dot com
Anonymous
July 20, 2004 2:21:44 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Menno van Rooij wrote:

> 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??

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
!