---
title: C405 Electrical Power and Lighting Systems
tags:
  - exclude-from-word-count
  - type/media/reference
up: "[[iecc_international-energy-conservation-code]]"
---
# C405 Electrical Power and Lighting Systems

## C405.2 Lighting controls.

Lighting systems shall be provided with controls that comply with one of the following.

* **1.** Lighting controls as specified in Sections C405.2.1 through C405.2.8.

* **2.** Luminaire level lighting controls (LLLC)
    and lighting controls as specified in Sections C405.2.1, C405.2.5 and C405.2.6.
    The LLLC luminaire shall be independently capable of:
 
    * **2.1.** Monitoring occupant activity to brighten or dim lighting when occupied or unoccupied, respectively.
    * **2.2.** Monitoring ambient light, both electric light and daylight, and brighten or dim artificial light to maintain desired light level.
    * **2.3.** For each control strategy, configuration and reconfiguration of performance parameters including; bright and dim setpoints, time-outs, dimming fade rates, sensor sensitivity adjustments, and wireless zoning configurations.

**Exceptions:** Lighting controls are not required for the following:

* **1.** Areas designated as security or emergency areas that are required to be continuously lighted.
* **2.** Interior exit stairways, interior exit ramps and exit passageways.
* **3.** Emergency egress lighting that is normally off.

### C405.2.1 Occupant sensor controls.

Occupant sensor controls shall be installed to control lights in the following space types:

1. Classrooms/lecture/training rooms.
2. Conference/meeting/multipurpose rooms.
3. Copy/print rooms.
4. Lounges/breakrooms.
5. Enclosed offices.
6. Open plan office areas.
7. Restrooms.
8. Storage rooms.
9. Locker rooms.
10. Corridors.
11. Warehouse storage areas.
12. Other spaces 300 square feet (28 m^2) or less
    that are enclosed by floor-to-ceiling height partitions.

**Exception:**
Luminaires that are required to have specific application controls
in accordance with Section C405.2.5.

#### C405.2.1.1 Occupant sensor control function.

Occupant sensor controls in warehouses
shall comply with Section C405.2.1.2.
Occupant sensor controls in open plan office areas
shall comply with Section C405.2.1.3.
Occupant sensor controls in corridors
shall comply with Section C405.2.1.4.
Occupant sensor controls for all other spaces
specified in Section C405.2.1
shall comply with the following:

1. They shall automatically turn off lights
    within 20 minutes after all occupants have left the space.

2. They shall be manual on
    or controlled to automatically turn on the lighting
    to not more than 50-percent power.

3. They shall incorporate a manual control
    to allow occupants to turn off lights.

**Exception:**
Full automatic-on controls with no manual control
shall be permitted in corridors, interior parking areas,
stairways, restrooms, locker rooms, lobbies, library stacks
and areas where manual operation would endanger occupant safety or security.

#### C405.2.1.2 Occupant sensor control function in warehouse storage areas.

Lighting in warehouse storage areas shall be controlled as follows:

1. Lighting in each aisleway
    shall be controlled independently of lighting
    in all other aisleways and open areas.

2. Occupant sensors shall automatically reduce lighting power
    within each controlled area
    to an unoccupied setpoint of not more than 50 percent of full power
    within 20 minutes after all occupants have left the controlled area.

3. Lights that are not turned off by occupant sensors
    shall be turned off by time-switch control
    complying with Section C405.2.2.1.

4. A manual control shall be provided
    to allow occupants to turn off lights in the space.

#### C405.2.1.3 Occupant sensor control function in open plan office areas.

Occupant sensor controls in open plan office spaces
less than 300 square feet (28 m^2) in area
shall comply with Section C405.2.1.1.
Occupant sensor controls in all other open plan office spaces
shall comply with all of the following:

1. The controls shall be configured so that general lighting
    can be controlled separately in control zones with floor areas not greater than 600 square feet (55 m^2)
    within the open plan office space.

2. General lighting in each control zone shall be permitted to automatically turn on upon occupancy within the control zone.
    General lighting in other unoccupied zones within the open plan office space
    shall be permitted to turn on to not more than 20 percent of full power or remain unaffected.

3. The controls shall automatically turn off general lighting in all control zones
    within 20 minutes after all occupants have left the open plan office space.

    **Exception:** Where general lighting is turned off by time-switch control complying with Section C405.2.2.1.

4. General lighting in each control zone
    shall turn off or uniformly reduce lighting power
    to an unoccupied setpoint of not more than 20 percent of full power
    within 20 minutes after all occupants have left the control zone.

#### C405.2.1.4 Occupant sensor control function in corridors.

Occupant sensor controls in corridors shall uniformly reduce lighting power to an occupied setpoint not more than 50 percent of full power within 20 minutes after all occupants have left the space.

**Exception:**
Corridors provided with less than two footcandles of illumination on the floor at the darkest point with all lights on.

## C405.10 Voltage drop.

The total _voltage drop_ across the combination of customer-owned service conductors,
feeder conductors and branch circuit conductors
shall not exceed 5 percent.
