RMU
Ring main unit
A secondary-distribution switchgear assembly with a selected combination of switching functions.
GA objects
Symbols · VPIS
Voltage presence indicating system
Capacitively coupled indicator on MV switchgear that shows whether each phase of a cable or busbar is energised.
In plain English
What does Voltage presence indicating system mean?
Voltage presence indicating systems are built into medium-voltage switchgear and ring main units. A capacitive divider in the bushing or insulator feeds a low-voltage indicator for each phase, and test sockets allow phase comparison before connecting cables or closing onto another source.
A simple example
An indicator showing no voltage is not proof that the circuit is dead. Safe isolation still requires the approved test method and earthing procedure, and the symbol does not show the indicator's thresholds or whether it is self-testing.
What the drawings help you do
Check one indicator per phase is shown. Do not treat a dark indicator as proof of isolation. A VPIS indicates presence of voltage; a voltmeter measures its value.
This particular reference
Capacitively coupled indicator on MV switchgear that shows whether each phase of a cable or busbar is supplied with operating power. A VPIS indicates presence of voltage; a voltmeter measures its value.
- Normally open / normally closed
- The contact state in the normal condition defined for the drawing.
- Phase
- One of the related AC waveforms in a power system.
- Rating
- A value stating the conditions for which equipment is specified.
Read the source: Secondary-distribution switchgear and ring main units · IEC graphical symbols for diagrams
SLD / Schematic · VPIS
What it represents
Voltage presence indicating systems are built into medium-voltage switchgear and ring main units. A capacitive divider in the bushing or insulator feeds a low-voltage indicator for each phase, and test sockets allow phase comparison before connecting cables or closing onto another source.
An indicator showing no voltage is not proof that the circuit is dead. Safe isolation still requires the approved test method and earthing procedure, and the symbol does not show the indicator's thresholds or whether it is self-testing.
How to read it
- Check one indicator per phase is shown.
- Do not treat a dark indicator as proof of isolation.
Information to show or reference
- Show coupling point per phase
- Reference test sockets
- State applicable switchgear panel
A distinction that matters
A VPIS indicates presence of voltage; a voltmeter measures its value.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Secondary-distribution switchgear and ring main units
Public secondary-distribution switchgear context where voltage presence indication is fitted.
IEC graphical symbols for diagrams
IEC context for graphical symbols used in diagrams; no IEC graphic is reproduced.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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