N
Neutral conductor mark
A mark on a single-line conductor group identifying which conductor is the neutral, often drawn as a small circle on a stroke.
IEC
IEC · PEN
PEN conductor mark
A mark identifying a combined protective and neutral conductor, as used in TN-C sections of a supply.
In plain English
What does PEN conductor mark mean?
The PEN mark identifies one conductor that performs both the protective and neutral functions. It appears in TN-C and TN-C-S arrangements, typically between the supply transformer and the main switchboard, where the PEN is later separated into N and PE at a defined point.
A simple example
A PEN conductor must not be switched or isolated on its own, and once separated into N and PE the two must not be rejoined downstream. A drawing that shows a PEN mark should therefore also show the separation point clearly. The mark says nothing about minimum conductor size, which local wiring rules set for PEN conductors.
What the drawings help you do
Find the point where the PEN is split into N and PE. Check that no switching device opens the PEN conductor alone. A PEN conductor combines N and PE functions; a neutral mark shows a conductor that has no protective role.
This particular reference
A mark identifying a combined protective and neutral conductor, as used in TN-C sections of a supply. A PEN conductor combines N and PE functions; a neutral mark shows a conductor that has no protective role.
- Winding
- A coil of conductor inside an electrical machine or transformer.
- Rating
- A value stating the conditions for which equipment is specified.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: Definition of standardised earthing schemes · Earthing connections
IEC · PEN conductor identification on a conductor group
Independent IEC-context illustration; not certified IEC geometry.
Shown as an independently authored educational illustration. Use the cited publication and drawing legend to verify the required drafting form.
SLD / Schematic · PEN
What it represents
The PEN mark identifies one conductor that performs both the protective and neutral functions. It appears in TN-C and TN-C-S arrangements, typically between the supply transformer and the main switchboard, where the PEN is later separated into N and PE at a defined point.
A PEN conductor must not be switched or isolated on its own, and once separated into N and PE the two must not be rejoined downstream. A drawing that shows a PEN mark should therefore also show the separation point clearly. The mark says nothing about minimum conductor size, which local wiring rules set for PEN conductors.
How to read it
- Find the point where the PEN is split into N and PE.
- Check that no switching device opens the PEN conductor alone.
Information to show or reference
- Show the PEN to N and PE separation point.
- Avoid single-pole switching of the PEN.
- Confirm PEN sizing against the applicable wiring rules.
A distinction that matters
A PEN conductor combines N and PE functions; a neutral mark shows a conductor that has no protective role.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Definition of standardised earthing schemes
Public installation-guide definitions of TN-C and TN-C-S schemes.
Earthing connections
Public guide to earthing connection elements.
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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