Noark Electric Main Distribution Board (MDB)

The Noark Electric Main Distribution Board (MDB) is an IEC 61439-2 compliant low-voltage switchboard architecture optimized for transformer secondary distribution, plant mains, and building central distribution. It combines Noark’s Ex9 series moulded-case circuit breakers (MCCBs) and Ex9C contactors with a type‑tested busbar system, selectable incoming ACB/ACB‑equivalents and modular feeder bays. Assemblies are engineered and type‑verified to IEC 61439-1/-2 criteria (temperature-rise, short‑circuit withstand, clearances/creepage and mechanical integrity) and integrate component compliance to IEC 60947 for switching devices. Typical electrical envelopes cover rated currents up to 6300 A and short‑circuit ratings in the 50–100 kA/1 s range depending on busbar size and bolted‑joint specification; temperature‑rise behaviour is verified by test or calculation per IEC 61439-1 Annexes. Noark Ex9 MCCBs (16 A–1600 A) are used for outgoing feeders and selective protection; electronic trip units, thermal‑magnetic releases, and adjustable long‑time/short‑time/instant settings permit coordination with upstream devices. Ex9C contactors provide motor switching and are specified for auxiliary and motor feeder bays in the MDB. For higher incoming ratings (beyond 1600 A single device), designs employ air circuit breakers (ACBs) or parallel busbar arrangements; manufacturers often pair Noark feeder devices in an assembly alongside proven ACB platforms such as SIVACON, ABB MNS, or Eaton Prisma Set for incoming metered and protected mains when required by system fault levels. Form of separation is selectable from Form 2b through Form 4b per IEC 61439 definitions: compartmentalized busbar/feeders, segregated functional units, and full internal separation for enhanced maintenance safety. IP ratings are configurable IP31–IP54 for indoor installations; IP65/66 options are achievable with enclosure gasketing and certified door arrangements. Protection capabilities include comprehensive earth‑fault, residual current devices (RCD/RCB), selective overcurrent coordination, and integration of electronic control & metering (class 0.5s or better CT/VT metering modules). Hazardous area adaptation requires component and enclosure compliance to IEC 60079 (explosion protection) and is performed via segregation or use of certified Ex components. For EPCs and panel builders the Noark Electric MDB offers a cost‑competitive, type‑verifiable building block: use Ex9 feeders and contactors for routine distribution, specify a type‑tested busbar system, and select incoming ACB/measurement platforms to match site short‑circuit levels. This approach delivers robust IEC 61439 assemblies suitable for commercial, industrial and infrastructure projects while enabling OEM flexibility and coordination with established frameworks like SIVACON, MNS and Prisma Set for high‑power mains.