This new section addresses receptacles in offices. Office plug loads are now the largest power density loads in most office buildings. The Standard now requires both controlled and uncontrolled 120-volt receptacles in each private office, open office area, reception lobby, conference room, kitchenette in office spaces, and copy room. The controlled outlets must be clearly different from uncontrolled outlets. The two principal ways to comply include:
1. For each uncontrolled outlet, provide a controlled outlet within 6 feet; or,
2. Use split wired duplex receptacles, with one uncontrolled and one controlled.
For open office areas, separate controlled and uncontrolled circuits must be provided to the workstations. If workstations are not installed at the time of occupancy, then when installed they must be equipped with non-residential power strips having motion controls built into the workstation, or alternatively, use the controlled and uncontrolled circuits already built in to the building system.
The controlled outlets must be automatically switched off in the same manner as required for general lighting, as described in Section 130.1(c.). The most common means will be a local motion sensor that can be connected to control both general lighting and outlets and using the occupancy (not vacancy) control method. Another common method will be to employ time of day controls with manual override switches.
Note that plug strips with motion sensors CANNOT be used to meet this requirement. The intent is to have built-in, hardwired power controls. Wireless motion sensors can be used, but the actual power switch must be hardwired.
The requirement for controlled receptacles in all of these spaces allows plug loads to be turned off for energy savings, and perhaps, for demand response. These particular space types were singled out because they commonly employ portable lighting and other loads that can be automatically controlled to save energy.
There are important exceptions not requiring a controlled outlet including:
•Clock outlets (mounted 6’ or more above the floor)
•Outlets for copiers, printers and other IT equipment (with the exception of personal computers) in copy rooms.
•Outlets for refrigerators and water dispensary devices in kitchenettes.
In general, the most cost effective approach may be:
A. Private Offices, Conference Rooms, and other Spaces with Periodic Occupancy
A common motion sensor can control general lighting and receptacles. If needed because of different voltages, an auxiliary relay can be connected to the sensor. Likewise, with an auxiliary relay, the lighting system could be operated in the vacancy mode, and the controlled receptacles in the occupancy mode, thus permitting lights to be off while receptacles are on.
B. Lobbies, Break Rooms, and other Spaces with Frequent Occupancy During Business Hours
Time of day controls, with either a motion sensor or switch override, can switch the controlled receptacles. Programmable relay panels or controllable breakers can be used, or for less complex projects, a combination of motion sensors and programmable time switches can accomplish the same task. Note that if motion sensing is used, controls need to be room-by-room or space-by-space, but if time of day controls with manual override are used, whole circuits can be controlled together.
C. Open Office Areas
Receptacles in open office areas can be controlled either by the building’s automatic shut-off system, or by controls integrated into the furniture systems. If the building provides controls, the most reliable system will most likely employ relays or controllable breakers, with manual override switches for zones within an open office space. A system using motion sensors might also be considered if sensors can be added as needed to address partitioning of the workstations thus ensuring proper operation. Systems contained within workstation systems are an acceptable alternative provided that they are hardwired as part of the workstation wiring system.
D. Networked Control Systems and Building Automation Systems
Most advanced lighting and energy control systems can be easily designed to accommodate outlet controls.
Certain office appliances, e.g. computers and fax machines, need to be powered all the time to provide uninterrupted services. These would be connected to the uncontrolled receptacles. Other appliances, e.g. task lamps, personal fans and heaters, monitors, do not need to be powered without the presence of occupants. They are considered as controllable plug loads and would be plugged into the controlled receptacles for automatic shutoff controls. A hardwired control system provides the capability and convenience for automatic plug controls. Ultimately, it depends on building occupants to determine the appliances to be controlled.
In open office areas, it is better to implement occupancy sensor control at each workstation (cubicle) to maximize the opportunities of shutoff controls. System furniture (cubicle) is usually
equipped with more than one internal electrical circuit and some of these circuits can be dedicated for controllable plug loads. Electric circuit connectors for system furniture are modularized and, therefore, split between controlled and uncontrolled circuits has to be made at a junction box. If external occupancy sensor switches are used, they all need to be wired to the corresponding junction box and the overall system wiring is complicated. 'In 'addition, off-the-shelf occupancy sensors are designed to be mounted on walls, not onto system furniture. For the above reasons, office furniture with embedded occupancy sensor controls are the ideal choice for occupancy sensor controls in open office areas.
Section 130.5 requires that, in any building or sign having mandatory provisions for demand response (DR), controls and equipment for DR shall be capable of receiving and automatically responding to at least one standards-based DR messaging protocol.
This requirement builds on the requirements of the following sections:
•Section 130.1(e), which requires the lighting in buildings over 10,000 square feet to have automatic demand responsive control.
•Section 130.3(a)3, which requires electronic message centers over 15 kW to have automatic demand responsive control.
•Section 1401.0(b)2I, which requires lighting alteration projects to include automatic demand response in the altered space under certain circumstances, such as when wiring is added or modified, or when the lighting load in the space is increased.
Note that this requirement only makes the building DR ready. It does not require buildings to actually respond to a demand signal. The decision to employ demand response is up to the building owner or manager, the utility company, and/or a governing authority.
Demand response signal is defined in Section 100.1 of the Standards as “a signal sent from the local power utility, independent system operator (ISO), or designated curtailment service provider, to a customer, indicating a price or a request to modify electricity consumption for a limited time period”.
The requirements of Sections 130.1(e) and 130.5(e) do NOT mean that a building has to be capable of responding to real time price signals. A building that is capable of responding to a request to reduce load when grid reliability is threatened (for instance with black outs) is sufficient to meet the requirements of the Standards.
Demand response is becoming increasingly important as it permits the temporary reduction of electric load on the grid when extreme weather or supply constraints cause electricity demand to come close to the grid’s maximum supply capabilities. It is also seen as a means to allow building operators to control electricity costs, as future prices are expected to change constantly as a function of overall system demand.
Because mandatory demand response (“DR”) is relatively new, standards and systems are still being developed and evolving. For this reason, Section 130.5 (e) does not specify a particular protocol or system, but rather lets it be specified by the utility company or other authority.