Help with medium voltage "earth switch"source 2

[jraef]

We manufacture Metal Enclosed MV (5 and 15kV class) motor control gear to ANSI specs for the N. American market, but we have recently been getting a lot of interest from worldwide customers. In the specifications and one-line diagrams we receive, they call for "earth switches" that appear to be on the load side of the controller. It looks as if this switch grounds all 3 conductors when (hopefully) the unit is not in use or being serviced(?). Since this is not a requirement in ANSI specs we have no information on what these are and where to find them. I have Googled the terminology and found numerous references to switchgear manufacturers having them as a standard feature of their design, but I am looking for the component itself so that we can integrate it into ours. Failing that, I would at least like to find a stand-alone device that I can recommend for them to add in the field. Any suggestions?

"Venditori de oleum-vipera non vigere excordis populi"

 

[atizapan]

GET IN TOUCH WITH KONNEKT IN MEXICO,konnekt@prodigy.net.mx, THEY CAN DESIGN EARTH ( GRUOND ) SWITCHES FOR YOU , AS WELL DISCONECT SWITCHES .
ATIZAPAN

 

[ScottyUK]

jraef,

Normally these devices are integrated into switchgear by the manufacturer because they have mechanical interlocks to prevent the switch closing onto a live bar. These switches typically have no switching capability at all, being solely intended for off-circuit operation. I would think any of the European manufacturers would source a switch for you. Try VA-Tech or maybe Whipp & Bourne as a couple of starting points. I'll have a dig through my files today for a couple more possibilities.

If you manage to get hold of one of these things and add it as a retrofit in the field, please consider adding a Castell or Kirk key interlock from the source breaker to prevent someone killing themselves by closing the earth onto a live bar.


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If we learn from our mistakes,
I'm getting a great education!

 

[jraef]

Thanks ScottyUK, that is exactly what I was looking for.

"Venditori de oleum-vipera non vigere excordis populi"

 

[desertfox]

Hi jraef

Good advice from Scotty, I used to work for Whipp & Bourne and they do have earth switches but I don't think they sell
them as a seperate unit. Also must switchgear earth switches that I have had an input to in terms of design usually have a 3 or 1 second short circuit current rating and a making capacity in case someone closes an earth switch onto a fault ie:- if the earth swicth is located on an incomer unit.
You could also try ABB Calor Emag which are based in Germany.

Regards

desertfox

 

[matwong]

It is kind of common feature in British designed switchgear. Suggest that you can get hold of the IEC62271-102 (or IEC60129)which I guess it may be what your customers based their requirements on.