Yes, you can definitely use power packs and low voltage occupancy sensors to control your four lighting circuits. It's often a more cost-effective and flexible solution than a lighting contactor, especially for multiple circuits. Here's a breakdown of the optimal approach

Understanding the Components:
Occupancy Sensors

These detect movement in the stockroom and send a low-voltage signal (typically 24V DC) when occupancy is detected.

Power Packs

These act as relays. They receive the low-voltage signal from the occupancy sensor(s) and switch the high-voltage (120V/277V etc.) power to the lighting circuit on or off.

The Design

Here's a breakdown of how to configure your system:1.

Zoning and Sensor Placement

Carefully consider the layout of your stockroom. Think about shelving, aisles, and areas that might be blocked from sensor view. Position your (3) occupancy sensors to provide overlapping coverage of the entire stockroom. You want to ensure there are no "dead spots" where someone could be present and the lights don't turn on. Overlapping coverage ensures reliability even if one sensor is temporarily blocked. Consider different types of occupancy sensors:

Passive Infrared (PIR)

Detects heat signatures. Good for areas with clear lines of sight, but can be blocked by objects.

Ultrasonic

Detects movement using sound waves. Less susceptible to blockage but can be triggered by airflow.

Dual Technology

Combines PIR and Ultrasonic for the most reliable detection and reduced false triggers.

Ceiling Mount

Best for general coverage.

Wall Mount

Can be useful for long, narrow aisles.2.

Power Pack Selection



Voltage

Choose power packs that match the voltage of your lighting circuits (e.g., 120V, 277V, or universal voltage).

Amperage

Ensure the power pack's amperage rating is sufficient to handle the load of all the lights connected to that circuit. Add up the wattage of all the lights on each circuit, and divide by the voltage to get the amperage. Always choose a power pack with an amperage rating that is higher than your calculated load. A safety factor of 20% is recommended.

Number of Circuits

You'll need a power pack for each of your (4) lighting circuits.

Sensor Input

Ensure the power pack is compatible with the low-voltage output of your chosen occupancy sensors (typically 24V DC).

Wiring Type

Power packs come with different wiring configurations. Usually, you'll have: Line In (Hot, Neutral, Ground) Load Out (Switched Hot, Neutral, Ground) - connects to the lights. Sensor Input (+ and -) - connects to the occupancy sensors.3.

Wiring Diagram (General Concept)



Power Source

Each power pack needs to be connected to a constant, unswitched power source (line voltage - e.g., 120V or 277V).

Lighting Circuits

Connect each lighting circuit (Hot, Neutral, Ground) to the Load Out terminals of its corresponding power pack.

Occupancy Sensors



Common Wiring (Important!)

Wire all three occupancy sensors in parallel to the low-voltage input of each of the four power packs. This means that any sensor detecting occupancy will activate all four power packs. Connect the + and - (or designated) wires from each sensor to the corresponding + and - (or designated) terminals on each power pack's sensor input. You will need to splice these connections. Some advanced sensors may have communication capabilities for daisy-chaining or networked control. While these features can be used, they aren't necessary for basic occupancy control.4.

Commissioning and Adjustments

Once everything is wired, carefully test the system. Adjust the time delay settings on the occupancy sensors to the desired duration (how long the lights stay on after no motion is detected). Typically, 10-20 minutes is a good starting point for a stockroom. Adjust the sensitivity settings on the occupancy sensors as needed to minimize false triggers.

Advantages of Power Packs & Low-Voltage Sensors vs. a Lighting Contactor



Lower Cost

Generally less expensive than a lighting contactor system, especially for controlling multiple circuits.

Flexibility

Easier to adjust lighting zones and sensor locations if your stockroom layout changes.

Scalability

Easier to add more sensors or lighting circuits in the future.

Energy Savings

More precise control can lead to greater energy savings.

Ease of Installation

Often simpler to install than a large contactor system, especially for someone familiar with low-voltage wiring.

Individual Circuit Control

Allows for more granular control. You could potentially have one circuit that stays on longer than others (e.g., near the entrance/exit).

Important Considerations and Safety



Local Codes and Regulations

Always comply with all applicable electrical codes and regulations in your area. This includes using appropriate wiring methods, conduit, and junction boxes.

Qualified Electrician

If you are not comfortable working with electrical wiring, hire a qualified electrician to perform the installation. Working with electricity can be dangerous.

Power Off

Always disconnect power to the circuits you are working on before making any connections.

Grounding

Ensure that all components are properly grounded.

Wiring Diagrams

Follow the wiring diagrams provided by the manufacturer of the occupancy sensors and power packs exactly.

Load Calculation

Calculate the total load of each lighting circuit carefully to ensure that the power packs are adequately sized. Overloading a power pack can lead to failure or even a fire hazard.

Example Products (Illustrative Only - Consult with a Supplier)



Occupancy Sensors

Wattstopper DT-300 Series (Dual Technology) Leviton ODC Series (Ceiling Mount PIR)

Power Packs

Wattstopper BZ-150 Power Pack* Greengate/Eaton GP Series Power Pack

In Summary:

Using power packs and low-voltage occupancy sensors is an excellent way to control the lighting in your stockroom. It's cost-effective, flexible, and can provide significant energy savings. Just be sure to plan your layout carefully, choose the right components, and follow all safety precautions. Remember to consult with a qualified electrician if you have any doubts about the installation process. Good luck! Flag for review