NEC Requirements Guidelines

Understanding Emergency & Standby Systems

At PSI Control Solutions, our top priority is to provide clients with the absolute best. That means offering great products, of course, but it also means providing relevant information as well. Informed clients can make better choices and will find that the products they choose satisfy their needs more thoroughly. And satisfaction is at the top of our list at all times. Recent changes in the NEC, particularly around NEC 700.3(F), have created new demand for our emergency power products. At the same time, there exists a lot of confusion in the marketplace as to how to best meet the new requirements and, more importantly, what products best meet your specific needs. PSI Control Solutions is here to help—our experts have been supplying power solutions and safety equipment to businesses nationwide for years.

What Is an Emergency System?

NEC 700.2 defines an emergency system as one that is legally required by any governmental agency having jurisdiction. It goes on to state that when normal power fails, this system must provide power automatically to supply power essential to human life.

What Is a Legally Required Standby System?

Like an emergency system, a legally required standby system is legally required. This system supplies “non-emergency” loads such as HVAC equipment, telephone/radio equipment, smoke evacuation systems, lighting systems (but not egress or emergency lighting), or necessary industrial process systems.

What Is an Optional Standby System?

This system is not legally required and is chosen only for convenience. Because of this difference, the rules differ greatly from the rules applicable to an emergency system or a legally required standby system.

Code 700.3(F) Simplified

The code taken from NFPA’s 2017 National Electrical Code® Handbook reads: “If the emergency system relies on a single alternate source of power, which will be disabled for maintenance or repair, the emergency system shall include permanent switching means to connect a portable or temporary alternate source of power, which shall be available for the duration of the maintenance or repair.” In simpler terms, the provision essentially asserts that when a permanent generator is under maintenance or repair, a permanent switching mechanism needs to be installed for portable generator hookup. The simplest way to comply with this code is to use a manual transfer switch that will transfer between your permanent generator and a set of Cam-Lok® connectors located on the manual transfer switch enclosure, where the temporary generator can be plugged in. In addition to having this secondary system available, the new code also requires that the secondary system be permanently connected via hardware to your existing system. The complete emergency power system must also be monitored so that you can easily and quickly determine that the main generator has been disconnected from the power system completely. This is primarily for safety reasons, but it also helps ensure procedure is correctly followed and avoids any potential complications.

Legally Required Emergency Systems

NFPA 2017 / NEC 700. Emergency Systems

NEC 700.2

  • Legally required by a governmental agency
  • Applies to buildings such as hospitals and public utility facilities

NEC 700.3(F)

NEC 700.3

NEC 700.2

  • If supplying power essential to human life, transfer equipment shall be automatic (i.e. Automatic Transfer Switch); mechanical or electrical interlocking is required

NEC 700.12 & NEC 700.5

  • Transfer shall not exceed 10 seconds
  • Transfer equipment shall be automatic
  • Transfer equipment shall supply only emergency loads

NEC 700.6

  • Audible and visual signals are required, both when in use and when not functioning

Generator Docking Station with Main Breaker Dual Purpose Generator Docking Station Load Bank Cam-Lok Cables Combo MTS & Gen Tap Box Automatic transfer switch Cam-Lok Cables

Legally Required Standby Systems

NEC 701. Legally Required Standby Systems

NEC 700.

  • Legally required system supplying “non-emergency” loads, such as HVAC, telephone, smoke evacuation, lighting (but not egress or emergency lighting), or necessary industrial process systems

NEC 701.3

NEC 701.5

  • Transfer equipment shall be automatic (i.e. Automatic Transfer Switch)
  • Unlike emergency transfer equipment, it is not prohibited from supplying other loads

NEC 701.6

  • Audible and visual signals are required both when in use and when not functioning

Generator Docking Station with Main Breaker Dual Purpose Generator Docking Station Load Bank Combo MTS & Gen Tap Box automatic transfer switch Cam-Lok Cables Cam-Lok Cables

Optional Standby Systems

NEC 702.

  • This system is not legally required; it is chosen for convenience

NEC 702.4(B)

NEC 702.4(B)(1)

  • When manual transfer equipment is used (i.e. Manual Transfer Switch), the “user” can manually select the load connected to the optional standby system by manually turning off certain circuit breakers

NEC 702.4(B)(2)

  • When/If automatic transfer equipment is used (i.e. Automatic Transfer Switch), the standby system shall be sized to the full load being transferred (unless using automatic load shedding)

NEC 702.5(Exception)

NEC 702.6 Audible and visual signals are required when in use, except for when portable generators are employed

MTS

Combo MTS Cam-Lock Cables

Adhering to NEC Guidelines

The simplest solution to meet the new code requirements is our combination manual transfer switch and generator tap box, which:

  • Provides switching means
  • Has Cam-Lok® connections hard-wired to the transfer switch
  • Is ready for easy roll-up generator hookup

The combination switch would be installed permanently so you are prepared for maintenance/repair on your permanent generator.

Stay NEC-Compliant with PSI Control Solutions

Have any further questions, or need to purchase a combination manual transfer switch and generator tap box so that you adhere to the new NEC codes? The team at PSI is here to help! Our experts have been supplying power solutions and safety equipment to businesses nationwide for years.