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Remote Head Wire Gauge & Distance Tables Instruction

Remote Head Wire Gauge & Distance Tables (AWG 18–10)

Grab-and-go tables to size copper wire for remote heads using a ~5% voltage drop target. Includes one-way distance limits for 6V / 12V / 24V systems across AWG 18–10, a quick formula, and worked examples. For products, see LED remote head emergency lights; for fundamentals, use the remote head sizing & wiring guide.

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Last updated: October 2025

Wire Sizing Voltage Drop UL 924 • NFPA 101

How to Use These Tables

  1. Pick your system voltage (6V / 12V / 24V).
  2. Total the branch load in watts (all heads powered on that run at once).
  3. Find the row for your watts and the column for your wire gauge.
  4. The value shown is the approx. one-way max distance (ft) to stay near a 5% drop target.
  5. If your run is longer: upsize wire or step up voltage (see 12V vs 24V for long runs).

Assumptions & Method

  • Target: ~5% voltage drop at full emergency load.
  • One-way distance shown (round-trip accounted for in calculations).
  • Copper resistance @ 20 °C (ohms/1000 ft): AWG 18 = 6.385, 16 = 4.016, 14 = 2.525, 12 = 1.588, 10 = 0.999.
  • Formula: I = P/V, Vdrop ≈ I × R (using round-trip length), Vdrop ≤ 0.05V.
  • Reality checks: Battery voltage sags during the 90-minute test; temperature and terminations matter. Verify brightness at the farthest head near the end of the test.

Tables — 12V Systems (One-Way Max Distance @ ~5% Drop)

12V branch loads and allowable one-way distance by copper AWG
Load (W) AWG 18 AWG 16 AWG 14 AWG 12 AWG 10
5 113 ft 179 ft 285 ft 453 ft 721 ft
10 56 ft 90 ft 143 ft 227 ft 360 ft
20 28 ft 45 ft 71 ft 113 ft 180 ft

Tables — 24V Systems (One-Way Max Distance @ ~5% Drop)

24V branch loads and allowable one-way distance by copper AWG
Load (W) AWG 18 AWG 16 AWG 14 AWG 12 AWG 10
5 451 ft 717 ft 1,141 ft 1,814 ft 2,883 ft
10 226 ft 359 ft 570 ft 907 ft 1,441 ft
20 113 ft 179 ft 285 ft 453 ft 721 ft

Tables — 6V Systems (One-Way Max Distance @ ~5% Drop)

6V branch loads and allowable one-way distance by copper AWG
Load (W) AWG 18 AWG 16 AWG 14 AWG 12 AWG 10
5 28 ft 45 ft 71 ft 113 ft 180 ft
10 14 ft 22 ft 36 ft 57 ft 90 ft
20 7 ft 11 ft 18 ft 28 ft 45 ft

Worked Example

Goal: Two 5 W heads on one branch (10 W) at 12 V using AWG 16. From the 12V table, 10 W @ AWG 16 ≈ 90 ft one-way. If your route is 120 ft one-way, you’re over the 5% target—either upsize to AWG 14 (≈ 143 ft) or step up to 24V (10 W @ AWG 16 ≈ 359 ft). Always verify at the end of the 90-minute test.

Branch Design Tips

  • Calculate segment-by-segment on shared branches using the maximum simultaneous load on each segment.
  • Favor home runs to farther heads to keep shared current low on long segments.
  • Mind connections: each splice adds resistance—keep them tight and minimal.
  • When in doubt, step up wire gauge or voltage and confirm with a live 90-minute test.

FAQs: Wire Gauge & Distance

Are these distances conservative?

They’re practical estimates for planning with ~5% drop and copper at room temperature. Battery sag, temperature, and connections can reduce brightness—test live and leave margin.

Do these tables handle multiple heads?

Yes—use the total branch wattage for the portion of the run you’re evaluating. On shared segments, use the load that flows through that segment.

Should I choose 24V just for distance?

Often helpful for long runs or higher loads. But for short runs, 12V is fine and simpler for inventory. See the companion post 12V vs 24V for long runs.

LED Remote Head Emergency Lights Remote Head Sizing & Wiring Guide