Which remote heads work with which host units? Use this plain-English matrix to match voltage, wattage, and environment ratings—plus a quick checklist to avoid the classic pitfalls. For product options, see LED remote head emergency lights; for fundamentals, start with the remote head sizing & wiring guide.
Last updated: October 2025
Fast Compatibility Checklist
- Voltage matches exactly (6V ↔ 6V, 12V ↔ 12V, 24V ↔ 24V).
- Host is explicitly remote-capable and lists a remote capacity (W).
- Total remote watts (sum of heads) ≤ host remote capacity at 90 minutes, with 10–20% margin.
- Wire gauge supports distance (≈ 5% drop target). See wire gauge & distance tables.
- Environment rating (indoor/damp/wet, vandal-resistant) matches the location.
- 90-minute test: farthest head still bright near end-of-discharge.
Compatibility Matrix (Heads ↔ Hosts)
Use these typical pairings to sanity-check your plan. The “Max # Remote Heads” assumes the remote share only of the host capacity (excludes any built-in lamps on the host). Adjust down if the host also powers its own lamps from the same battery.
| System Voltage | Remote Head (each) | Host Remote Capacity | Max # Remote Heads* | Environment Options | Notes |
|---|---|---|---|---|---|
| 12V | LED 4 W MR-16 / PAR | 20 W | 5 | Indoor • Damp • Wet | Good for short runs; check drop beyond ~100 ft with AWG 18–16. |
| 12V | LED 5 W MR-16 | 36 W | 7 | Indoor • Damp • Wet | Longer branches may need AWG 14 or step to 24V. |
| 24V | LED 5 W MR-16 | 50 W | 10 | Indoor • Damp • Wet | 24V halves current vs 12V—distance headroom improves markedly. |
| 24V | LED 7 W PAR36 | 72 W | 10 | Indoor • Damp • Wet • Vandal-Resist. | For large open areas/exterior doors; confirm wire size for long runs. |
| 6V | LED 2–4 W mini head | 20 W | 5–10 (lower watt heads) | Indoor • Damp | Best for very short runs; voltage drop rises quickly at 6V. |
*Max # Remote Heads = floor(Host Remote Capacity ÷ Head Wattage). If the host also powers its own lamps from the same battery, subtract their watts first.
Quick math: A 36 W remote-capable host with 4 W heads can supply up to 9 remotes for 90 minutes—if it doesn’t also run built-in lamps. If it does, subtract built-ins, then divide.
Voltage & Wiring Basics
- Never mix voltages: 6V heads need 6V hosts; 12V ↔ 12V; 24V ↔ 24V.
- Distance matters: Higher voltage lowers current and reduces drop—see 12V vs 24V for long runs.
- Wire gauge: Target ≈ 5% drop at the farthest head; upsize copper or shorten runs. Use the wire gauge tables.
- Polarity & terminations: Follow head/host diagrams; some heads are polarized. Keep splices minimal and tight; torque terminals per spec.
- Documentation: Keep a one-line diagram, head schedule (W, qty), conductor gauges, and run lengths in the job folder for AHJ review.
Environment & Ratings
- Indoor (dry): Thermoplastic heads are common.
- Damp/Wet: Gasketed, sealed heads with listed IP/NEMA ratings; use proper fittings and hub seals.
- Vandal-resistant: Metal housings, tamper-resistant hardware, and guards for vulnerable locations.
- Cold weather: Consider locating the host in conditioned space; choose heads rated for low ambient if outdoors/freezers.
- Hazardous locations: For C1D2 areas, use heads explicitly listed for the classification and appropriate T-code (covered in a separate C1D2 guide).
Common Pitfalls
- Choosing heads before confirming host remote capacity and system voltage.
- Forgetting to subtract built-in head watts when allocating remote capacity.
- Under-sizing wire on long branches; far head dims near end-of-discharge.
- Mismatched environment rating (indoor head used outdoors; no IP/NEMA).
- Mixing brands without checking polarity conventions and warranty notes.
FAQs
Can I mix brands?
Often yes—if voltage, wattage, and polarity match. Always confirm with both spec sheets and note warranty language for cross-brand installs.
My host says “36 W remote capacity.” Does that include its built-in heads?
Usually “remote capacity” refers to watts available for external heads only. If a spec lists only total battery capacity, subtract built-in lamp watts first.
Why do my far heads look dim?
Voltage drop. Check round-trip length and gauge; aim for ≈ 5% drop at the tail. Stepping up to 24V or upsizing wire typically fixes it.