Remote Capable Emergency Lights - Sizing & Wiring Instruction

Remote Heads for Emergency Lighting: Sizing, Wiring & Code (+Spacing & Head Calculator)

What remote heads are, when to use them, how to size and wire them, and how to pick a compatible remote-capable system that meets code without overbuilding. For product options, see our LED remote head emergency lights and remote-capable emergency lights.

Last updated: October 2025

Educational Guide Sizing & Wiring UL 924 • NFPA 101

In This Series: Remote Head Specific Guides

These deep dives support the pillar without targeting the collection’s primary product terms. We’ve curated links to stay within the internal link budget.

Application-Specific Remote Head Guides

What Are Remote Heads?

Remote heads are low-voltage emergency lamp fixtures (no internal battery) that connect to a separate emergency light’s battery source. During an outage, the host unit switches to battery and powers its built-in lamps and any connected remote heads over a dedicated low-voltage circuit.

Because they don’t carry their own batteries, remote heads are compact, discreet, and economical. They’re available in indoor thermoplastic, outdoor/wet-location models, and heavy-duty/vandal-resistant variants to match the environment. They must be paired with a remote-capable emergency light designed to supply external load.

When & Why to Use Them

  • Long corridors & turns: Extend coverage around corners or to corridor ends without adding multiple battery units.
  • High ceilings: Aim heads from elevated points while keeping the battery unit accessible at a service height.
  • Outdoor egress: Feed weather-rated heads outside from a protected interior battery source.
  • Large open rooms: Distribute heads across exits/aisles while powering them from one central unit.

Key Benefits

Diagram: key benefits of remote heads for emergency lights—wider reach, fewer batteries to maintain, lower visual impact, flexible aiming, and environment-matched options.
Key Benefits — Remote Heads for Emergency Lights
  • Wider reach: Put light where built-in heads can’t, using one power source.
  • Fewer batteries to maintain: Centralized power simplifies testing and replacements.
  • Lower visual impact: Small heads blend into ceilings and soffits.
  • Flexible aiming: Adjust beams to eliminate dark spots and overlap coverage.
  • Environment-matched: Indoor, wet-location, and vandal-resistant options.

Tradeoffs & Limitations

  • Low-voltage wiring needed: Plan conduit/runs and terminations.
  • Single point of failure: If the host unit/battery fails, all connected heads go dark.
  • Capacity limits: Total remote load must fit the host’s wattage for a full 90-minute runtime.
  • Upfront host sizing: Higher-capacity units cost more but support more/larger heads.
  • Field verification: Aim and test furthest heads—especially near end of the 90-minute cycle.

Selecting a Remote-Capable System

Confirm the host unit explicitly supports remote load and that its remote capacity (in watts) covers your plan (host’s own lamps + all remote heads) for the full 90-minute emergency duration.

Voltage: 6V vs 12V

  • Match voltages exactly: 6V heads to 6V hosts, 12V heads to 12V hosts—never mix.
  • 6V: Good for short runs and small loads.
  • 12V: Better for longer runs and higher total wattage (lower current, less voltage drop).

Wattage & Battery Capacity

Add up the host’s lamp wattage and all remote heads. Stay within the host’s rated watts for 90 minutes—and leave 10–20% margin for aging and temperature. If you exceed capacity, upgrade the host or reduce heads/wattage.

Runtime Math — Quick Example: Host remote capacity = 36 W. Built-in lamps: 2 × 4 W = 8 W. Planned remotes: 4 × 4 W = 16 W. Total emergency load = 24 W. Required energy for 90 min = 24 W × 1.5 h = 36 Wh. Pass (meets host capacity with ~0% headroom) → Better: remove one 4 W remote or choose the next-size host to keep a 10–20% margin.

How Many Remote Heads?

There’s no universal count—only a wattage limit. Example: a 20 W remote capacity can feed five 4 W heads, or two 8 W heads plus one 4 W head, etc., provided 90-minute runtime is maintained.

Distance & Wiring

  • Minimize run length: Place hosts centrally relative to heads.
  • Size wire for drop: Long runs need thicker copper (e.g., 14/12 AWG). Keep voltage drop ≲ ~5% at end-of-line.
  • Favor 12V for distance: Higher voltage tolerates longer runs with less loss.
  • Test at 90 min: Verify furthest head is still bright at the end of the cycle.

Voltage-Drop — Rule of Thumb: Estimate current as I = P/V; for long runs, increase conductor size until calculated drop is about ≤5% at the farthest head.

Environment Ratings

  • Indoor (dry): Standard thermoplastic heads.
  • Damp/Wet: Sealed, listed heads (often polycarbonate or die-cast), gasketed lens, proper IP/NEMA rating.
  • Cold weather: Consider heaters or locate host in conditioned space.
  • Vandal-prone: Metal heads with tamper-resistant hardware; guards as needed.

Installation Tips

  • Host placement: Accessible for testing/battery swaps; status LED and test button visible.
  • Labeling: Mark remote circuits and junctions for future service.
  • Aim precisely: Overlap beams to eliminate dark spots; document aiming angles.
  • Circuit supervision (if available): Choose hosts that flag remote-circuit faults.
  • Maintenance: Include remote heads in monthly/annual test routes; clean lenses; re-aim if bumped.

Application Walkthroughs

🏭 Warehouse (High Ceilings)

Mount a 12V, high-capacity host at service height by the maintenance room. Run low-voltage circuits to multiple LED remote heads mounted high at aisle ends and over receiving. One battery powers all heads; servicing stays ground-level.

🏢 Office Corridor (L-Shaped)

Place a compact host in the floor’s electrical closet; locate small ceiling remote heads at both corridor ends. In outage, the host powers its own lamps and both remotes—clean look, full coverage, one battery to maintain.

🎭 Auditorium (Discreet Aesthetics)

Hide a high-output unit backstage. Feed low-profile or recessed remote heads aimed at aisles and exits. No bulky boxes in view; one source supports distributed heads throughout the venue.

Remote-Head Spacing Estimator

Use this quick estimator to size initial spacing for corridors and similar egress paths. It combines a spacing-to-mounting-height check with a lumen-method average (1.0 fc default) and shows the tighter result. Finalize with photometrics and your AHJ.

Inputs

This is a pre-layout estimate. Verify with photometrics to meet average/minimum/ratio requirements.

Results


Quick S/MH Method
S/MH ≈
Max spacing ≈
Lumen Method
Needed locations:
Spacing along length ≈
Recommended (use tighter value)
Place heads every
Estimated count:
Sanity
Beam Ø on floor:
Width coverage ratio:

Installation Tips

  • Host placement: Accessible for testing/battery swaps; status LED and test button visible.
  • Labeling: Mark remote circuits and junctions for future service.
  • Aim precisely: Overlap beams to eliminate dark spots; document aiming angles.
  • Circuit supervision (if available): Choose hosts that flag remote-circuit faults.
  • Maintenance: Include remote heads in monthly/annual test routes; clean lenses; re-aim if bumped.

Application Walkthroughs

🏭 Warehouse (High Ceilings)

Mount a 12V, high-capacity host at service height by the maintenance room. Run low-voltage circuits to multiple LED remote heads mounted high at aisle ends and over receiving. One battery powers all heads; servicing stays ground-level.

🏢 Office Corridor (L-Shaped)

Place a compact host in the floor’s electrical closet; locate small ceiling remote heads at both corridor ends. In outage, the host powers its own lamps and both remotes—clean look, full coverage, one battery to maintain.

🎭 Auditorium (Discreet Aesthetics)

Hide a high-output unit backstage. Feed low-profile or recessed remote heads aimed at aisles and exits. No bulky boxes in view; one source supports distributed heads throughout the venue.

Related Fire Code Guides

From the Fire code guide series:

FAQ

Can any emergency light power remote heads?

No. You need a unit explicitly designed for external load. Look for “remote capacity” or “remote-capable” in the specs.

How many remote heads can one unit support?

As many as the wattage allows while maintaining 90-minute runtime. Sum the host lamps + all remotes and stay within the host’s rated watts (leave margin).

How far can I place a remote head from the host?

It depends on voltage, load, and wire gauge. Longer runs need thicker wire; 12V handles distance better than 6V. Verify brightness at the furthest head after 90 minutes.

Can I mix 6V and 12V heads on the same system?

No. Voltages must match the host exactly. Never mix 6V and 12V on one circuit.

Are remote heads allowed outdoors?

Yes—use wet-location listed heads and appropriate wiring. Many teams feed exterior heads from an interior host to protect the battery.