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For qualified staff only

By 29. June 2020December 2nd, 2020No Comments


For qualified staff only


For some time now, the symbols “Installation, electrotechnical expertise” and “Installation, mechanical expertise” have increasingly been seen on electrical installation products, for example. These symbols are intended to indicate that specialist knowledge is required to install these products.

IEC 60417-6182
Installation, electrotechnical expertise

IEC 60417-6183:
Installation, mechanical expertise

Manufacturers would do well to refer to the necessary expertise during installation on the packaging, as they have little control over who actually installs the products in times of “do it yourself”.

Such symbols of the new generation are a good opportunity to have a look at the symbol statement and the design guidelines applied.


Because the two symbols were included in IEC 60417 “Graphical symbols for equipment”, the design principles of ISO/IEC 80416 must also be applied. Positioning the symbols on the basic figure (IEC 80416-1) results in the following picture:

  • Grid of the basic figure
    The octagon results from the two basic squares.
    Design principle applied.
  • Line widths 2 mm
    The octagon is a polyline with a corresponding line width.
    Design principle applied.
  • Distances
    Minimum distance between two parallel lines 3 mm
    Design principle not applicable, as there are no parallel lines
  • Filled areas
    … should be avoided…
    Design principle not observed, but because the symbols are used rather as safety signs, it is worth having a look at ISO 3864-3 “Design principles for graphic symbols for use in safety signs”, where surfaces are recommended to improve the recognizability.
The symbols were combined from several IEC 60417 symbols:

  • Symbol element: Octagon
    Standardized: based on IEC 60417-3308 with text STOP
    Meaning: Stop operation
    Meaning in the symbols: Stop
  • Symbol element: Person
    Standardized: IEC 60417-5391
    Meaning according to standard: Patient, obese
    Meaning in the symbols: Staff
  • Symbol element: Construction helmet
    Standardized: ISO 7010-M014
    Meaning according to standard: Wear a safety helmet
    Meaning in the symbols: commercial / technical
  • Symbol element: Electric lightning
    Standardized: IEC 60417-2302
    Meaning according to the standard: electrical energy
    Meaning in the symbols: Electrical
  • Symbol element: Open-end wrench
    Standardized: IEC 60417-0717
    Meaning according to standard: Call for maintenance
    Meaning in the symbols: Mechanics

If you put together the meaning of the individual symbol elements, you get the symbol statement:

“Stop, for mechanical or electrical specialists.”

This does not correspond to the desired interpretation. Of course, symbols and their meaning have to be learned. We do this, consciously or unconsciously all our lives. And that is exactly the point. We always encounter an octagon in everyday life as a STOP sign in road traffic.


So what could be the solution? We change the base symbol from a stop shape to a mandatory shape, the circle according to ISO 3864-1. If we put the meaning of the individual symbol elements together again, we now come to the symbol statement:

“Only, for mechanical or electrical specialists.”

Due to the uniqueness of the basic circle shape for mandatory signs, the symbol also works in black and white, if necessary. On this occasion you could adapt the person, the helmet and the electric flash to the symbols according to ISO 3864 and you will get a working mandatory sign.


The paradox is that these symbols, despite their supposed lack, can function well. For the laws of perception (everyday experience, interpretation, obviousness, association) very probably do indicate that the “stop octagon” refers to the viewer and not to the other symbolic content.

The considerations here are not intended to question standardized symbols in principle. The considerations are rather meant to motivate a structured way of working when developing your own symbols, in which I will gladly support you.

Symbols for download

ISO 60417:6182 and 6183 as CSL
Corel symbol library for Draw and DESIGNER from version X7 on and
Corel Stylesheet CDSS for efficiently changing object properties.
If you are working with a current version of Corel,
then first open the CSL and save it in the Corel version you are using.

ISO 60417:6182 and 6183 as EPS
ISO 60417:6182 and 6183 as PNG
ISO 60417:6182 and 6183 as SVG

The downloads are not subject to copyright protection.