Automatic Receptacle Controls

As an electrical engineer, staying up-to-date with the latest energy codes is crucial for designing efficient and compliant electrical systems. The 2021 International Energy Conservation Code (IECC) introduced significant changes, particularly in section C405.11, which focuses on automatic receptacle controls. Automatic receptacle controls have been required by ASHRAE 90.1 since 2010, but has only recently been added to the IECC.

Many devices such as computers, printers, and copiers run continuously, drawing power even when not in use. Automatic receptacle controls are intended to reduce this unnecessary energy consumption by automatically switching off receptacles when not in use. In this post, we'll dive into where these controls are required and explore methods for implementing these controls effectively.

Where are Automatic Receptacle Controls Required?

The 2021 IECC C405.11 mandates automatic receptacle controls in several key areas of new construction and major renovations. Below are they areas where receptacle controls are required:

1. Enclosed offices, conference rooms, print/copy rooms, breakrooms, classrooms, and individual workstations: At least 50% of the 125V, 15- and 20-amp receptacles installed in these spaces must have automatic controls. This requirement applies to receptacles installed in modular partitions and modular office workstation systems as well.

2. Modular furniture branch circuit feeders: A minimum of 25% of branch circuit feeders installed for modular furniture not shown on the construction documents must have automatic controls.

It's important to note that there are a few exceptions to these requirements. Automatic receptacle controls are not required for:

1. Receptacles specifically designated for equipment requiring continuous operation.

2. Spaces where automatic controls would endanger the safety or security of the room or building occupants.

3. Within a single modular office workstation, non-controlled receptacles are permitted to be located more than 12 inches but not more than 72 inches from the controlled receptacles serving that workstation.

Methods for implementing Automatic Receptacle Controls.

The 2021 IECC C405.11.1 outlines the specific requirements for automatic receptacle control functionality. Controls must be provided using one of the following methods:

1. Time-of-day scheduling with the ability to program separate schedules for each day of the week and for each portion of the building not exceeding 5,000 square feet (464.5 m2) and one floor. Manual occupant override for up to 2 hours must be provided, with each override switch controlling receptacles for an area not exceeding 5,000 square feet.

   1. This approach works well for areas like open offices where occupancy sensors might not pick up minor movements or corridors, lobbies, and warehouse storage spaces which might require receptacles to remain powered during times when the space is unoccupied for longer than 20 minutes. Time-clocks, programmable relays or smart receptacles with built-in scheduling capabilities can be used to achieve this functionality.

2. Occupant sensor control that turns off receptacles within 20 minutes of all occupants leaving a space.

   1. This method is particularly well-suited for private offices, conference rooms, and individual workstations. Be sure to select sensors with appropriate coverage areas and sensitivity settings to ensure optimal performance.

3. An automated signal from another control or alarm system that turns off receptacles within 20 minutes after determining the area is unoccupied.

   1. Plug load management systems are becoming more available as the need for energy management expands. These systems typically consist of smart receptacles, gateways, and software that allow for granular control and monitoring of individual receptacles. They can be programmed to turn off receptacles based on occupancy, schedule, or even energy consumption thresholds.

When selecting and implementing automatic receptacle controls, it's crucial to consider factors like ease of installation, compatibility with existing electrical infrastructure, and the specific needs of the space. Collaborating with the client, contractors, and manufacturers and staying informed about the latest products and technologies can help ensure a successful implementation.

In addition to the required methods for automatic control outlined above, the code also provides requirements for the receptacles being controlled as outlined below:

1. Either split-controlled receptacles with the top receptacle controlled must be provided, or a controlled receptacle must be located within 12 inches of each uncontrolled receptacle.

2. All controlled receptacles must be permanently marked in accordance with NFPA 70 and uniformly distributed throughout the space.

3. Plug-in devices do not comply with the automatic receptacle control requirements.

By understanding these detailed requirements and exceptions, electrical engineers can ensure that their designs are fully compliant with the 2021 IECC C405.11 automatic receptacle control provisions.

Conclusion

The 2021 IECC C405.11 automatic receptacle control requirements present both challenges and opportunities for electrical engineers. By understanding where these controls are mandated and exploring various implementation methods, you can design electrical systems that are not only code-compliant but also energy-efficient and user-friendly. Embrace these new requirements as an opportunity to showcase your expertise and contribute to a more sustainable built environment.

Written By

Donald Walker, PE

Electrical Group Leader

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