AC and LV Electrical Wiring Plan
By this point in the design process, I know where every item in the home theater will go, so I can now determine what electrical is needed and where to place it all. This page describes the theater's high- and low-voltage electrical design planning. High voltage refers to 120V AC electrical power for the room, and low voltage refers to wiring for speakers, the network, HDMI, IR control, and some control wiring.
Electrical, and Lighting Plan
Last Updated: 03/09/2025
Electrical Plan
Not much thought was put into the power distribution for the home theater. My general experience is that the equipment driving the home theater never continuously consumes anything close to its manufacturer's maximum rated power. Even though the manufacturer's power specifications are notoriously pessimistic, I added up the total equipment and lighting power just for fun. ere is the result:
-
Calculated Equipment Power = 2,081W (split - 1,081W, 1,000W)
-
Worst-case Lighting Power = 500W
A single 15A circuit can supply ~1.6kW (RMS). Given that the 2kW shown above is overly conservative, one circuit should be able to power the entire theater. However, when accounting for the existing electrical circuit assignments in the basement, I decided to use 3-15A circuits, but two were shared with neighboring basement rooms.
Here is the summary of the circuit arrangement, whose details can be seen in Figure 1:
-
Circuit #1—This circuit powers the outlets in the theater room. It connects the two subwoofers, a projector, and the recliners. This circuit also powers some outlets in the study next door.
-
Circuit #2—This is the lighting circuit. The room has five types of lights.
-
Four 5-in. recessed lights over the seating area.
-
Six soffit 3-in. recessed lights were added after the initial build.
-
Sconces on the side walls, 2 on each wall. Used for "mood" lighting.
-
A rope light on the riser around the riser.
-
Another rope light in the tray around the edge of the soffit.
-
Circuit #3—This dedicated circuit supplies power to the equipment shelves (not an equipment rack because shelves were less expensive). It powers all the electrical equipment except for the projector and subwoofers.
Two additional power design considerations were whether to use surge protection, how to use it, and whether to use any battery backup.
Figure 1. Detailed Electrical Distribution and Lighting Plan
Battery Backup
I did not add a battery backup for this theater. The one item that should have had a battery backup is the projector. The purpose of this backup would be to enable proper power down to preserve the lamp. Backing up other equipment is more convenient for some.
To back up the projector's battery, it is usually desirable to place the battery near the main equipment area. Mounting a battery backup system near the projector can be challenging, especially if it is ceiling-mounted. Placing the battery backup near the rest of the equipment enables it to back up some of this equipment if desired. To do this, I'd need to run the equivalent of a Romex extension cord through the wall, with one end having a male connector. This is shown in Figure 2. Kits are available, like this in-wall connection kit, which provides the correct connectors.
Figure 2. Projector to Remote UPS Connection That Should Have Been Done.
Surge Protection
Initially, no surge protection was planned (another sub-optimal decision ). I never lost equipment in the theater to a power outage or surge. Even though not originally planned for, almost by accident, some surge protection was used in the form of some quality power strips with built-in surge protection. Eventually, a whole-house surge protector was added to protect the house, including the theater room, but this is not considered part of the theater budget. See Figure 3. Some form a surge
Figure 3. Whole House Surge Protection, looks ready
Lighting Design
I am not sure I'd say there was much thought put into the lighting design. No specific design principles, layering, or calculations were done. The first idea was to address general lighting, which is covered by four 5-inch recessed lights over the seating area. Then, a rope light around the riser is used to illuminate it and avoid tripping. And for fun, a rope light to highlight the soffit's edge. The blue wiring and light symbols in Figure 1 show wiring and light placement.
Later, after painting the walls and ceiling in darker shades, we realized we needed to add more light to illuminate the room. Four overhead recessed lights typically provide enough light for this size room, but in this room, they did not. The room's periphery was not well-lit even when all the dimmers were set to 100%. This issue was resolved after the room was completed by adding six 3-inch recessed lights along the bottom of the soffits.
The 5 dimmer switches controlling these lights were quickly swapped to Z-Wave smart dimmers to automate lighting scenes.
Low Voltage Wiring - Speaker Wire, HDMI, etc.
Last Updated: 10/11/2024
The design of the low-voltage wiring, which includes a speaker, projector, and automation connections for this room, is pretty straightforward. See Figure 4.
Figure 4. Low Voltage Wiring Connector Locations
The design of the low-voltage wiring, which includes a speaker, projector, and automation connections for this room, is pretty straightforward. See Figure 4.
-
Speaker wiring—Wall connectors were placed near the expected 7.1.4 locations. Most speaker connections used a typical banana plug except for front ATMOS, in which connections were embedded and directly connected. The wire was routed in the walls using CL2-rated 12-gauge wire. The wire was thicker than necessary and stiff, making it challenging to handle. Multi-way banana receptacles were placed at each location.
-
HDMI Cabling—There were two cable runs.
-
An HDMI connector was placed at the projector location, and an HDMI v1.4 compliant cable was run. If the projector is upgraded, a new HDMI v2.1 cable must be installed. (MISTAKE: I should have run conduit for HDMI to make upgrades more accessible.)
-
Behind the projection screen, a second HDMI was run. This is intended for the day when >110-inch direct-view TVs become affordable. Then, a direct-view TV can replace the screen.
-
-
Subwoofer Coax—The room was wired for two subwoofers using two shielded audio cables with RCA connectors. (One connector was placed at the back of the room and one at the front. Since the theater is relatively narrow, the front and back of the room were chosen for the subwoofer locations.
-
IR Cabling—The original setup included an IR optical sensor, IR repeater, and network interface for controlling equipment via IR and Ethernet. However, it was simplified by adding the Harmony Elite remote and hub. Two IR blasters, one inside the theater and one on the equipment shelves, allowed automatic control via IR or network.
-
Network—The equipment shelves contain an Ethernet switch and Wi-Fi router, connecting devices via Ethernet when possible and Wi-Fi otherwise. Only one network connection exists inside the room, intended for the projector but never used. A hard-wired connection for a potential future TV on the front wall was considered but not implemented due to easy future installation.
Figure 5. Speaker Wall Plate (left). Projector Wall Plate (right)