The IEC 61439 series is divided into several parts, but and Part 2 are the most frequently referenced.
| Feature | IEC 61439-1 (General Rules) | IEC 61439-2 (Power Assemblies) | | :--- | :--- | :--- | | | All LV assemblies (distribution boards, busbar trunking, marinas, etc.) | Specific to power switchgear (main LV switchboards, motor control centers) | | Rated Voltage | Up to 1,000 V AC / 1,500 V DC | Typically up to 1,000 V AC (power frequency) | | Rated current | No lower limit | Usually above 100 A, but not exclusive | | Short-circuit withstand | General requirements up to 100 kA (typical) | Detailed requirements up to very high levels (e.g., 150 kA) | | Forms of separation | Defined in Part 1 (Form 1 to Form 4) | Referenced from Part 1, but with practical clarifications for power circuits | | Temperature rise limits | General limits (e.g., 70 K for terminals) | Same numerical limits, but with stricter attention to power dissipating components (busbars, circuit breakers) | | Internal arcing fault protection | Optional (Annex Z) | More commonly required (Arc Fault Containment) | iec 614391 and 2 pdf
. For decades, it had tried to keep low-voltage switchboards safe, but it was often confusing. It used riddles like "Type Tested" (TTA) and "Partially Type Tested" (PTTA), which left many panel builders scratching their heads. The IEC 61439 series is divided into several
Requirements for fixed, removable, and withdrawable parts. It used riddles like "Type Tested" (TTA) and