This engineering guide explains how to plan, specify, and install outdoor / wet-location exit sign + emergency light combo units without guesswork. It’s intentionally informational (not a shopping page) so it won’t compete with your parent category. We cover ratings (Wet Location vs. NEMA/IP), cold-weather battery strategy, lamp-head sizing, mounting, and compliance—so your team passes inspection the first time.
Last updated: October 2025
Positioning: Support the Category, Don’t Compete
This article is built to support the parent collection for wet-location exit sign & light combo units—not to outrank it. We avoid transactional wording and SKU lists, and focus on how to specify and install outdoor-rated combos correctly. When you’re ready to compare models, use the collection CTAs above. Until then, use this as your field guide to ratings, environmental risks, lamp-head performance, and code sanity checks.
Where Outdoor / Wet-Location Combos Make Sense
Any time an exit door opens to weather—or a fixture sees spray, wash-downs, wind-driven rain, or persistent condensation—you need an outdoor/wet-location combo. Typical use cases include:
- Exterior discharge doors: The last egress point must remain visible and illuminated in rain, snow, or fog. An outdoor-rated combo provides both the “EXIT” legend and doorway illumination from one device.
- Unconditioned stair towers & garages: Temperature swings and condensation can destroy indoor-only electronics. Weather-sealed housings and coated boards extend life.
- Food & transit facilities (wash-down): Regular hose-downs require gasketed enclosures, sealed heads, and drain/vent features so moisture doesn’t linger.
- Coastal or industrial environments: Salt, chemicals, and particulates corrode hardware and optics; choose corrosion-resistant materials and fasteners.
- Wind-exposed canopies & docks: Jetting rain reaches fixtures under canopies; use higher NEMA/IP ratings and appropriate conduit entries.
Scenario: A warehouse exit opens onto a partially covered loading zone. Forklifts and rain splash routinely hit fixtures. An outdoor-rated combo with sealed heads, a sloped top, and stainless hardware survives abuse that destroys standard indoor units.
Understanding Ratings: Wet Location vs. NEMA/IP
Wet Location (UL) indicates a fixture can be installed where it’s directly exposed to water (rain, splashing, or dripping). For more granular protection, manufacturers often publish NEMA or IP ratings:
- NEMA 3R: Outdoor use; protects against rain and sleet. Good under canopies with moderate exposure.
- NEMA 4: Gasketed enclosure resists windblown dust and rain and hose-directed water. A common baseline for wash-down areas.
- NEMA 4X: Like 4, plus enhanced corrosion resistance. Look for this in coastal facilities, food plants, and chemical environments.
- IP65/66: Dust-tight with protection against water jets; IP66 is higher pressure. Match the IP to cleaning practices (and keep the wand at a reasonable distance).
IK ratings (impact) are less common on combos but helpful in abuse-prone zones. If your site has carts, balls, or hail exposure, ask for impact data or lens/guard options.
Translation: If wash-down or driven rain is likely, aim for NEMA 4/4X or IP66. If continuous spray or chemical exposure is expected, choose 4X with stainless hardware and UV-stable lenses.
Designing for Weather: Seals, Corrosion & UV
Outdoor success is mostly about keeping water out—and letting any that gets in, out again fast. Look for:
- Continuous gaskets: One-piece, compression gaskets around the door and lamp heads reduce leak points. Spare kits are a plus.
- Weep/drain features: Some enclosures include designed drain paths. Don’t caulk every seam—follow the manual so you don’t trap water.
- Vents/pressure equalization: Microporous vents relieve pressure and reduce condensation without inviting water ingress.
- Corrosion-resistant fasteners: Stainless 304/316 hardware prevents seize-ups. Specify anti-seize for coastal installs.
- UV-stable plastics & lenses: Polycarbonate heads and legends should be UV stabilized to resist yellowing and embrittlement.
- Finish system: Look for powder coats designed for exterior use; in severe sites, consider 4X polymer or fiberglass housings with metal backplates.
Finally, plan the conduit strategy: top-entry with listed hubs where required, drip loops on liquid-tight, and sealants compatible with the enclosure’s plastic/paint. Never drill ad-hoc holes near gasket landings.
Cold-Weather Battery Strategy (Heaters, Chemistry)
Cold kills battery capacity. Outdoor combos need a battery approach that maintains 90-minute runtime when temperatures dip:
- Heater kits: Thermostatically controlled pads keep batteries within their happy range in freezing weather. Confirm power draw and that branch capacity supports it.
- Chemistry: Ni-Cd is tough and inexpensive but loses capacity in deep cold; LiFePO4 has better gravimetric energy and cycle life but still benefits from heaters in freezing environments. Check the fixture’s rated ambient.
- Recharge window: UL 924 expects an 87.5% recharge within ~24 hours. In cold conditions, verify the charger spec and consider seasonal test scheduling (e.g., full 90-minute tests after a “warm-up” period).
- Self-testing: Cold-rated self-diagnostics help catch heater or charger faults early. Make sure the status LED is visible from the ground.
Rule of thumb: If winter nights routinely drop below freezing, specify the cold-weather option. If you’re coastal but mild, prioritize corrosion resistance and UV stability over heaters.
Sizing & Spacing the Lamp Heads Outdoors
Outdoors is darker and less reflective than hallways. You’ll often need more output and wider beams to achieve code-clean illumination at the door and along the initial egress path. Use this quick field method to sanity-check before you run full photometrics:
- Define the target: Door threshold + first 10–20 ft outside. If the path turns, include that corner in your planning.
- Pick head wattage: For 7–8 ft mounting, start with two 5–7 W LED heads. Go 2×8–10 W for tall door surrounds, dark brick, or wide apron areas.
- Aim for uniformity: Offset one head slightly to graze the ground near the door; aim the other down-path. Avoid blasting vertical surfaces.
- Validate with a meter: At night, measure along a line: threshold, 5 ft, 10 ft, 15 ft. Document readings and aim tweaks in the closeout log.
- Extend with remotes if needed: If the apron is large, choose a remote-capable outdoor combo and add remote heads at the first bollard or corner to carry the light farther down the route.
Voltage drop note: For remote heads, calculate conductor size and distance. Outdoor cable runs get long fast; keep voltage drop under control so remote output stays within spec over the full 90 minutes.
Mounting & Ingress Management (Real-World Tips)
- Back-mount when possible: It shelters the housing and reduces wind-driven rain inside the enclosure. Use supplied gaskets and specified torque on fasteners.
- Canopies & end mounts: Where end/flag or ceiling mounts are needed, use weather-rated canopies and maintain slopes so water drains away from seams and heads.
- Anchors & substrates: Outdoor mounting surfaces vary. Verify anchor type (masonry vs. metal stud), edge distances, and allowed loads for heavier outdoor housings.
- Seal properly: Use manufacturer-approved sealants; avoid over-caulking bottom seams if the design relies on weep paths.
- Heat & sun: South-facing walls can cook electronics. If possible, shade with an overhang or select a housing/finish with higher thermal tolerance.
- Aim & lock: After night-aiming, fully tighten head fasteners. Document the aim directions so staff can restore them after a bump.
Compliance Notes: UL 924, NFPA 101, Local Rules
- UL 924: Confirms automatic transfer to battery and a 90-minute discharge supporting both the legend and lamp heads. Check the label and run a witnessed acceptance test.
- NFPA 101 / IBC / OSHA: Require continuous exit marking and minimum egress illumination. Make sure the legend color/size and arrow directions match your life-safety plan and local amendments.
- Local jurisdictions: Some cities (e.g., NYC, often Chicago) require specific materials or legend formats. For outdoor units, inspectors focus on ratings claims—ensure “Wet Location” and any NEMA/IP are clearly on the submittal.
- Testing & records: Keep the 30-second monthly and 90-minute annual logs. Self-diagnostics help, but follow your AHJ’s record-keeping rules.
TCO & ROI: Why Outdoor-Rated Combos Pay Back
Outdoor-capable combos cost more than indoor units, but they last longer where weather is the enemy. Fewer water-intrusion failures, fewer corroded fasteners, fewer yellowed lenses, and fewer “fail” tags during inspections add up. On multi-site portfolios, swapping problem doors to outdoor-rated combos quickly reduces truck rolls and spare-part spend.
Common Mistakes to Avoid (Quick Checklist)
- Using an indoor/damp unit at an exterior door—spec Wet Location (and NEMA/IP where needed).
- Ignoring cold weather—add heater kits or select chemistry/ratings for freezing temps.
- Under-lighting the apron—outdoors needs more watts and wider beams; validate at night.
- Over-caulking—don’t block designed weep paths; follow the enclosure manual.
- Skipping corrosion control—require stainless hardware and UV-stable optics near coasts.
- No records—log the 90-minute test, aim directions, and battery install date at closeout.
Editable Spec Language (Copy/Paste)
Provide outdoor / wet-location exit sign + emergency light combo units, UL 924 listed, suitable for [WET LOCATION] with rating [NEMA 4/4X or IP66] as scheduled.
Housing: weather-sealed enclosure with continuous gasket; corrosion-resistant hardware (stainless 304/316).
Input: 120/277 VAC; automatic solid-state transfer; low-voltage disconnect; brownout protection.
Battery: [Ni-Cd / LiFePO4], cold-weather heater kit where required; 90-minute minimum runtime supporting legend + both heads.
Legend: [RED/GREEN], [single/double-face], field-applied chevrons matching life-safety drawings.
Lamps: two adjustable LED heads, outdoor-rated optics, output sufficient to achieve egress illumination at door + initial path.
Options: self-diagnostics; remote-capable output [XX W] for additional outdoor heads; vandal guard.
Submittals shall indicate Wet Location and NEMA/IP rating; NYC/Chicago-compliant legends where applicable.
Install per manufacturer instructions; seal penetrations with listed fittings; verify aim at night; log 90-minute test.
FAQ
Will this post compete with the parent collection?
No. It’s an instructional guide (ratings, sizing, install, compliance). It avoids transactional language and routes product discovery to the collection pages via CTAs.
Wet Location vs. NEMA/IP—what should I put on the submittal?
List “Wet Location” and include a NEMA (3R/4/4X) or IP (65/66) rating matched to exposure. Inspectors look for clear claims when units live outdoors or see hose-downs.
Do I need a heater kit?
If winter nights approach freezing, yes. Heaters stabilize battery temperature so the unit still delivers a full 90-minute discharge. Verify branch capacity and specify the kit up front.
Can one outdoor combo power extra remote heads?
Choose a remote-capable model with an outdoor-rated remote wattage budget. Account for voltage drop and make sure the combined load (legend + onboard heads + remotes) still meets the 90-minute requirement.
What materials last near the ocean?
Look for NEMA 4X, stainless fasteners, UV-stable optics, and finishes designed for salt-spray. In severe sites, polymer or fiberglass enclosures with metal backplates are common.