Terminology and abbreviations

PE and the earthing symbol
Terminology and abbreviations 1:

PE is the abbreviation for "protective earth" and has the same meaning as the earthing symbol
Terminology and abbreviations 2:

Earth, ground

This document uses the term “earth” which is the same as the U.S. term “ground”.

T.b.d.

Still to be defined, value or description will follow in due course.

AC 230 V

A value preceded by "AC" or "DC" represents a nominal voltage or a nominal voltage range. The nominal voltage or the nominal voltage range may be provided with tolerances. (e.g., AC 230 V ±10%). The calculated total range then indicates the working range of the device.

Example:
DC 12 V refers to a 12 V battery, regardless of whether it is fully charged (13.7 Vdc) or discharged (10 Vdc).

230 Vac

A value followed by the unit Vac or Vdc is an instantaneous value that does not contain any additional tolerances.

50 Hz vs. 60 Hz

Unless otherwise specified, AC 230 V parameters are valid at a mains frequency of 50 Hz.

may

A keyword indicating a choice without implied preference.

shall

A keyword indicating a mandatory requirement.

should

A keyword indicating a choice with a clearly preferred method of implementation.