Upgrading a commercial property's exterior lighting from legacy metal halide (MH) fixtures to modern LED wall packs is one of the most impactful retrofits a facility can undertake. It delivers immediate improvements in energy efficiency, security, and aesthetics while significantly reducing long-term maintenance overhead. For electricians and maintenance teams tasked with this upgrade, a successful project goes beyond simply swapping fixtures; it requires careful planning, precise installation, and an understanding of the technology's nuances.
This guide provides a comprehensive, step-by-step framework for retrofitting metal halide wall packs to LED, ensuring a smooth, compliant, and effective transition that maximizes return on investment for the property owner.
Why Upgrade from Metal Halide? The Business Case
The move from MH to LED is driven by compelling operational and financial advantages. While the initial fixture cost is a factor, the long-term savings and performance gains create a strong business case for the investment.
Superior Energy Efficiency & ROI
Modern LED wall packs consume significantly less energy to produce the same or greater light output compared to their MH predecessors. It is common to see a 60-75% reduction in wattage for an equivalent or better level of illuminance. This translates directly into lower monthly utility bills and a rapid payback period. Furthermore, many high-performance LED fixtures are certified by the DesignLights Consortium (DLC), making them eligible for lucrative utility rebates that can shorten the ROI timeframe even further.
Drastically Reduced Maintenance
Metal halide lamps have a relatively short operational life, typically ranging from 6,000 to 15,000 hours, and they suffer from significant lumen depreciation over that time. LED fixtures, by contrast, are rated for much longer lifespans, often 50,000 to 100,000 hours or more to L70 (the point at which they degrade to 70% of initial lumen output). This longevity, defined by IES standards like LM-80 and TM-21, means fewer costly and labor-intensive replacement cycles, freeing up maintenance teams for other critical tasks.
Enhanced Performance and Safety
LEDs offer instant-on capability at full brightness, eliminating the warm-up and restrike delays inherent to metal halide technology. This is a critical advantage for security lighting tied to motion sensors. LEDs also provide a much higher Color Rendering Index (CRI), rendering colors more accurately and improving visibility for security cameras and personnel. The result is a safer, more secure perimeter. For detailed guidance on fixture arrangement, refer to our guide on Wall Pack Placement for Perimeter Security Coverage.
Pre-Retrofit Assessment: Planning for a Flawless Installation
A thorough site audit is the most critical phase of a retrofit project. Proactive planning prevents costly surprises during installation and ensures the chosen fixtures meet the facility's needs.
One of the most common mistakes is failing to account for existing conditions. I’ve seen projects delayed because the new fixture’s mounting plate didn't align with the existing junction box, or because the circuit couldn't handle the initial power draw.
Use this checklist to conduct a comprehensive site audit:
Site Audit Checklist
| Assessment Area | Key Checks & Considerations | Why It Matters |
|---|---|---|
| Existing Fixture | - Measure current light levels (foot-candles) on the ground and key surfaces. - Identify original fixture's delivered lumens, not just its wattage. - Note the color temperature (e.g., yellowish HPS vs. white MH). |
Prevents under-lighting or over-lighting. You are replacing lumens, not watts. This is the foundation of a successful lighting design. |
| Mounting & Physical | - Inspect junction box condition, depth, and screw alignment. - Verify conduit knockout locations on the new fixture vs. the old one. - Check for wall surface integrity (brick, concrete, metal siding). |
Mismatched junction boxes are a primary cause of delays and improper seals, leading to water ingress and premature failure. |
| Electrical System | - Confirm circuit voltage (e.g., 120V, 277V). Most commercial LEDs handle a 100-277V range. - Assess total load on the circuit. - Beware of inrush current. Multiple LED drivers energizing at once can trip older breakers. |
Ensures electrical compatibility and safety. Planning for inrush on circuits with over 10 fixtures by staggering startups can prevent nuisance tripping. |
| Lighting Controls | - Evaluate existing photocell placement. Is it free from shading or reflective surfaces? - Determine the need for 0-10V dimming to comply with energy codes or for added savings. |
A poorly placed photocell can cause the lights to cycle on and off incorrectly. Modern fixtures like the Wall Pack Light - Wall E series, 13000lumens, 5000K, AC 100-277V, Optional Dusk to Dawn often come with integrated, reliable photocells but placement is still key. |
Step-by-Step Retrofit Installation Guide
With a solid plan in place, the installation process is straightforward. Always adhere to the National Electrical Code (NEC) and local regulations.
Disclaimer: This guide is for informational purposes only. All electrical work should be performed by a qualified electrician in compliance with local codes and safety standards. Always follow the manufacturer's specific installation instructions.
Safety First: Lockout/Tagout
Before beginning any work, identify the correct circuit breaker for the wall packs being replaced. Turn it off and apply a lockout/tagout device to ensure the circuit cannot be accidentally re-energized. Use a multimeter to verify that power is disconnected at the fixture location.
Step 1: Remove the Old Metal Halide Fixture
Carefully open the housing of the old MH fixture. Disconnect the line, neutral, and ground wires. Loosen the mounting screws and remove the fixture from the wall. Be aware that older fixtures can be heavy and may contain a separate ballast and lamp, which must be disposed of according to local environmental regulations.
Step 2: Prepare the Mounting Surface
Inspect the junction box and surrounding wall surface. Clean away any dirt, debris, or old caulking. Confirm the gasket surface is smooth and that the box is securely fastened to the structure. This is the time to make any necessary repairs to the J-box or conduit entry points.
Step 3: Mount the New LED Wall Pack
Most LED wall packs have a two-part design: a backplate that mounts to the junction box and a main fixture body that hinges or slides into place.
- Feed the supply wires through the opening in the backplate.
- Secure the backplate to the junction box using the provided screws and gasket to create a watertight seal. A small detail I always recommend is applying a non-conductive silicone dielectric grease to threaded conduit entries to prevent corrosion and ensure a weatherproof seal for years to come.
- Ensure the gasket is seated correctly and tighten the screws to the manufacturer's recommended torque. Over-tightening can deform the gasket and compromise its IP (Ingress Protection) rating.
Step 4: Wire the Fixture
Connect the supply wires to the fixture wires using appropriate connectors (e.g., wire nuts):
- Black (Live) from supply to Black on the fixture.
- White (Neutral) from supply to White on the fixture.
- Green/Bare (Ground) from supply to Green on the fixture.
If using 0-10V dimming, connect the low-voltage dimming control wires (typically purple and gray) to the corresponding wires from your control system. Tuck all connections neatly inside the junction box.
Step 5: Secure the Fixture and Configure Controls
Hinge or slide the main body of the fixture onto the mounted backplate and secure it. If the fixture has an adjustable head or integrated photocell, make final adjustments. For photocells, ensure the sensor is aimed away from any artificial light sources and has a clear view of the sky. If the fixture is under a deep canopy, using a model with a remote photocell option may be necessary.
Step 6: Energize and Test
Remove your lockout/tagout device and re-energize the circuit. The LED fixture should illuminate instantly. If it has a photocell, you may need to cover the sensor to simulate darkness and confirm it turns on. Check for proper operation and ensure the light distribution meets the project goals.
Post-Installation: Maximizing Value
The job isn't done after the lights turn on. Proper documentation and understanding the technology are key to long-term success.
Myth Debunked: "A 100W LED Replaces a 400W Metal Halide"
A common misconception is that you can replace fixtures based on wattage alone. This is incorrect. The right way is to compare delivered lumens. A 400W MH lamp might produce 36,000 initial lumens, but it loses 30-40% of that in the first year. A high-efficacy 150W LED fixture might produce 20,000 stable lumens for a decade. The goal is to match the required foot-candles on the ground, not the input watts.
Rebate Documentation Checklist
To ensure success with utility rebate applications, meticulous record-keeping is non-negotiable. Reviewers will reject incomplete submissions. For each project zone, archive the following:
- UL/DLC Certificate: A printout from the UL Solutions Product iQ Database or DLC Qualified Products List.
- IES File: The photometric data file for the specific model installed.
- LM-79 Report: The performance test report for the fixture.
- Installation Photos: Clear before-and-after photos of the installed fixtures.
- Purchase Invoice: Proof of purchase for the fixtures.
Key Takeaways
Retrofitting from metal halide to LED wall packs is a smart investment that enhances safety and reduces operational costs. Success hinges on a professional approach:
- Plan Thoroughly: Conduct a detailed site audit to assess lumens, mounting conditions, and electrical systems before ordering materials.
- Install Safely: Always follow NEC guidelines, local codes, and manufacturer instructions, with a focus on creating a durable, weatherproof seal.
- Think in Lumens: Base your product selection on the required light output (lumens), not the old fixture's wattage.
- Document Everything: Keep meticulous records of compliance documents (UL, DLC, LM-79) to streamline and guarantee rebate approvals.
By following these steps, electricians and facility teams can execute flawless LED wall pack retrofits that deliver lasting value and performance for any commercial property.
Frequently Asked Questions (FAQ)
How long does shipping take? Shipping generally takes 3-7 business days, depending on your location. All orders are processed and shipped from our local warehouses.
What is the warranty on your wall pack lights? We offer a 5-year warranty on our lighting products, covering any defects or quality issues. This ensures peace of mind and protects your investment.
Can I wire the wall pack to a switch instead of using the photocell? Yes. If you prefer manual control via a switch, you can simply bypass or remove the photocell sensor during installation. Cover the sensor input with the included cap to maintain the fixture's weatherproof rating.
What should I do if the light flickers? Flickering can be caused by several issues. First, ensure the fixture is receiving a stable voltage within its specified range (e.g., 100-277V). Second, check for loose wiring connections. Third, if on a dimmer, ensure the dimmer is a compatible 0-10V model and is wired correctly. If the problem persists, it may indicate a faulty driver, which would be covered under warranty.