where should the moving part of a disconnector be located when breaking gets applied, on the energized side or on the disconnected side? Is there any standard?? Suppose a non ring, simple grid and mention the authenticated sources for as much as possible please.

  • \$\begingroup\$ @IgnacioVazquez-Abrams: It doesn't sound like university homework to me. It is a legitimate question that would come up when doing real-world engineering design. \$\endgroup\$ Commented Feb 27, 2014 at 8:01
  • \$\begingroup\$ Quickly looking at some drawings I have lying around, it is always drawn with the moving part on the disconnected side. I will do a bit more research when I get home. \$\endgroup\$ Commented Feb 27, 2014 at 8:10
  • \$\begingroup\$ I appreciate Li-aung, and looking forward to more of your comments. \$\endgroup\$ Commented Feb 27, 2014 at 9:49

1 Answer 1


The moving part is almost always on the load (de-energised) side, for the following reasons:

  1. If it is three-position disconnector (closed-open-earthed), the load must be connected to the moving part so that it can be earthed.

  2. If you have a fuse-switch-disconnector, the fuses are typically on the moving part. You want the moving part to be de-energised so you can safely access/inspect the fuses.

There may be more reasons but those are the main ones that come to mind right now.

Be aware that the orientation shown on the drawing often does not reflect reality, and at higher voltages many disconnectors are either rotary (double-break) or centre-break types, even though they might be shown on the SLD using the standard disconnector symbol.

  • \$\begingroup\$ ^ What he said. \$\endgroup\$ Commented Feb 28, 2014 at 9:42
  • \$\begingroup\$ Thank you, is there any standard ?! \$\endgroup\$ Commented Feb 28, 2014 at 11:20
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    \$\begingroup\$ There is no standard, you need to make a decision based on what is best for the situation. In terms of drawings, switches/breakers/disconnectors are usually drawn with the moving part at the bottom. \$\endgroup\$
    – Li-Wen Yip
    Commented Mar 4, 2014 at 0:59
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    \$\begingroup\$ I'd add that there are standard symbols, but whether people use them or not is another matter. In Australia/NZ for example we have AS/NZS 1102 - Graphical symbols for electrotechnical documentation. \$\endgroup\$
    – Raggles
    Commented Jul 13, 2014 at 23:45

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