At-a-Glance

Introduction

Exit signs run 24/7, so small electrical decisions affect safety, inspections, and utility costs. This guide demystifies voltage (120/277V), dual-voltage drivers, and real-world wattage—plus when a zero-power sign is appropriate—so you can specify confidently and stay code-ready.

Types of Exit Signs & Power Characteristics

Each sign family uses a different illumination method and has distinct electrical needs.

Incandescent Exit Signs

Older technology using filament lamps. About 30–40 W per sign at 120V (sometimes 277V). High energy/maintenance cost due to frequent relamping.

LED Exit Signs

The current standard: 1–5 W typical draw. Most are dual-voltage (120/277V) and include a UL 924 90-minute battery pack. Long life and lowest operating cost.

Photoluminescent Exit Signs (Zero-Power Alternative)

No wiring/electricity. Charge from ambient light during occupancy; emit a visible glow during outages (typically 90+ minutes when properly charged). Use where steady light is available or wiring is impractical.

Fluorescent/CFL Exit Signs

8–16 W typical. More efficient than incandescent but largely obsolete (mercury content, shorter life) compared to LED.

Tritium Self-Luminous Exit Signs

0 W and no charging light required. Glows continuously (10–20 years). Requires licensed recycling at end-of-life.

Understanding Voltage: 120V vs 277V

Exit signs are typically designed for 120V or 277V circuits. Many models are labeled 120/277V (dual-voltage), meaning they’re compatible with both.

What is 120V?

Common in residential and light commercial buildings. If lighting circuits are 120V, exit signs can connect without special transformers or gear.

What is 277V?

Used in larger commercial/industrial facilities as part of a 480V three-phase system. Often shared with overhead lighting to reduce losses over distance.

Why Dual-Voltage Matters

Dual-voltage drivers reduce mismatch risk and simplify installs. Connect to the correct leads and cap the unused pair.

Choosing the Right Voltage

• Small offices/retail: usually 120V circuits.
• Large commercial/warehouses/schools: often 277V circuits.

Safety note: Always verify circuit voltage. A 120V-only sign on a 277V line can fail catastrophically. Dual-voltage LED models minimize that risk.

Understanding Wattage & Efficiency

Wattage is the power a sign consumes to stay lit. Because exit signs run continuously, wattage drives long-term cost.

Why Wattage Matters

Small differences compound over 8,760 hours/year. Typical comparisons:

LED Efficiency Advantages

LED signs draw a fraction of the power and run cooler, cutting bills and HVAC load. Many drivers optimize output for long battery runtime under UL 924.

Zero-Power Alternatives

Photoluminescent and tritium (self-luminous) exit signs use no electricity. Photoluminescent requires consistent charging light during occupancy; tritium glows continuously and must be recycled by a licensed facility at end-of-life.

See self-luminous exit signs for fully dark or remote areas.

U.S. Safety & Compliance Codes

Know the core rules before you buy:

OSHA (29 CFR 1910.37)

• Exit signs must be continuously illuminated when occupied.
• Externally lit signs need ≥ 5 foot-candles on the face.
• Self-luminous/photoluminescent signs ≥ 0.06 foot-lamberts luminance.
• Letters ≥ 6″ high with ¾″ stroke.

NFPA 101 – Life Safety Code

• Use UL 924-listed equipment.
• Provide ≥ 90 minutes of emergency operation.
• Include an emergency power source (battery or circuit).
• Place so signs are visible along the route (often ≤ ~100 ft apart).

Energy Efficiency by Sign Type

LED

1–5 W, >10-year life, low heat—top choice for energy and maintenance savings.

Photoluminescent

0 W; requires steady ambient light for charging and placement that preserves visibility.

Fluorescent/CFL

Higher power than LED, contains mercury, declining availability.

Incandescent

Highest energy/maintenance cost; generally a replacement priority.

Tritium

0 W; continuous glow 10–20 years; end-of-life recycling required.

How to Choose the Right Exit Sign

1. Determine circuit voltage: 120V or 277V. Prefer dual-voltage models to avoid mismatch.
2. Pick a power source: hardwired LED + battery for most jobs; consider zero-power options if wiring is impractical.
3. Verify emergency backup: ≥ 90 minutes per UL 924.
4. Check UL 924 listing: required for inspections.
5. Set faces & arrows: single/double-face; field-selectable chevrons.
6. Match the environment: wet-location, vandal-resistant, hazardous-location as needed.
7. Consider aesthetics: edge-lit/recessed for design-sensitive spaces.

FAQ

Is 277V more efficient than 120V?

LED driver efficiency is similar; 277V mainly benefits large sites by reducing current and line losses on long runs.

Do dual-voltage signs auto-sense?

Most require landing on the correct lead set (120V vs 277V). Always follow the wiring diagram.

Can I mix 120V and 277V exit signs?

Yes, if circuits are separate. For simplicity and spares, standardize on dual-voltage SKUs.

Are zero-power signs always acceptable?

They must meet listing/placement rules; verify with your AHJ, and ensure charging light for photoluminescent.

Conclusion

Get voltage right, minimize wattage, and confirm UL 924 backup. For most installs, LED exit signs with battery deliver the best code, cost, and reliability balance. Where wiring is difficult—or energy use must be zero—photoluminescent or self-luminous options can fit, provided they meet local rules.

Additional Resources:

• Exit Sign Regulations
• Battery Powered Exit Signs
• Edge Lit Exit Sign Appeal
• New York City Exit Signs Info