Technical references for electrical switchboard design
Devpan’s Technical Information section brings together the calculation tables, standard definitions and application rules most often needed in the design, manufacture and site installation of low voltage switchboards. To help engineers, technical draftspeople and field teams make the right choices, we explain each topic with reference to the relevant standards (such as IEC 61439, IEC 60529 and the Turkish standard TS 212).
Under the headings below you will find practical references, from cable and busbar current-carrying capacities to forms of internal separation, and from IP protection ratings to current transformer C/k setting. Each page includes tables and formulas and also answers frequently asked questions.
Technical information topics
- What Is Form Separation? IEC 61439 Forms (1-2-3-4) – levels of internal separation in switchboards and selection criteria.
- Cable Current-Carrying Capacities – TS 212 current-carrying table for YVV (NYY) cables.
- Copper Busbar Current-Carrying Capacities – current ratings by copper busbar cross-section.
- What Is an IP Rating? – IEC 60529 IP code table and meanings.
- Current Transformer C/k Setting – C/k calculation formula and setting table.
Frequently asked questions
Which standards are the tables in the Technical Information section based on?
The tables and definitions are based on current international and national standards, such as IEC 61439 for low voltage switchboards, IEC 60529 for degrees of protection and TS 212 for cable current-carrying capacities.
Should I choose cable or busbar?
The choice depends on the current to be carried, the installation space, heating and cost. You can determine the right cross-section for your project by comparing the tables on the Cable Current-Carrying Capacities and Copper Busbar Current-Carrying Capacities pages.
Why does the form of separation matter?
The form of separation defines the level of internal partitioning in the switchboard and directly affects personnel safety during maintenance and continuity of service. Choosing the right form is critical for both safety and compliance with the standard.