IEC 61554:1999

Foreword
1 Scope
2 Definitions
3 Requirements
      3.1 General
      3.2 Instrument Size Designation
      3.3 Dimensions
      3.4 Individual Cut-Out Mounting
      3.5 Common Cut-Out Mounting
Annex A (informative) Dimensions for instruments with round
                      housing
Figure 1 - Square Housing
Figure 2 - Rectangular Lateral Housing
Figure 3 - Rectangular Upright Housing
Figure 4 - Common Cut-Out Mounting
Table 1 - Sizes and Tolerances

Applies to electrical and electrically operated indicating, recording and control instruments. Establishes dimensional interchangeability between instruments made by different manufacturers. To fulfil this requirement, a defined set of dimensions has been chosen. Using these dimensions, it should be easy to combine instruments of different sizes on the same panel making good use of the available panel space and to produce a satisfactory layout.