Electrical systems and rooms



Electrical rooms and mechanical, electrical and plumbing spaces are often an afterthought when it comes to building design and planning. This lack of preparation can have unfortunate consequences on the cost, operations and flexibility of the electrical systems for the future.

NFPA 70: National Electrical Code dictates the minimum amount of space needed around the equipment for access, operations, safety reasons and conduit installation. Together, with the actual equipment sizes, this defines the overall minimum dimensional requirements of the room.

However, good engineering practice will often go beyond code in accommodating enhanced operation and maintenance of electrical equipment within the room. In addition, the NEC does not cover the many important considerations in coordinating with architectural, structural, HVAC or fire protection disciplines. This session will provide that detail.

This session will also briefly touch on electrical distribution systems, electric vehicle charging stations and integration of a host of electrical aspects.


Learning objectives:

  • Know the types of interior electrical spaces that factor into new building design: main equipment rooms, electrical distribution pathways and local/branch equipment rooms.
  • Understand how different types of electrical equipment affect room design.
  • Understand that code-required working space and dedicated space needs must be met. Explain the applicable code requirements including NFPA 70: National Electrical Code.
  • Consider building type, intended occupancy, size and future expectations of both the building and the electrical system. Analyze the requirements for coordinating with structural, architectural, fire protection and HVAC requirements.
  • Demonstrate good electrical system design through case study examples.



  • Brian Rener, PE, LEED AP, principal, mission critical leader, SmithGroup, Chicago
  • James Lessard, PE, electrical firm discipline leader, vice president, CannonDesign, St. Louis