Project GuideNEC 2023 · 2026 · Updated Apr 2026

Outdoor Landscape Lighting: Complete Wiring Guide

Q: What wire size do I need for outdoor landscape lighting?

Use 12 AWG copper or 12 AWG aluminum on a 20A breaker at 120V. This is based on NEC 2023 Table 310.16 ampacity with 110.14(C) termination limits and 125% continuous load sizing per 210.19(A)(1).

Q: Does outdoor landscape lighting require GFCI?

Yes. GFCI protection is required per NEC 210.8(A)(3).

Outdoor Landscape Lighting: Use 12 AWG copper on a 20A breaker at 120V. GFCI protection required per 210.8(A)(3).

Wire (Cu)12 AWG

Wire (Al)12 AWG

Breaker20A

GFCIRequired

Bill of materials

Outdoor lighting comes in two categories: low-voltage (12V, governed by NEC Article 411) and line-voltage (120V, standard branch circuit rules). Low-voltage landscape lighting uses a transformer and 12-16 gauge landscape wire with no burial depth requirement. Line-voltage outdoor fixtures require GFCI, weatherproof boxes, and proper burial depth for underground runs.

Low-voltage (12V) landscape lighting: transformer must be listed for outdoor use, landscape wire (12-16 AWG direct burial) has no NEC burial depth requirement but 6 inches is recommended. Line-voltage (120V): all outdoor outlets require GFCI per 210.8(A)(3), underground wiring must meet 300.5 burial depths, use wet-rated fixtures and in-use covers. Photocells and timers simplify control. LED fixtures dramatically reduce wire sizing needs.

Low-voltage transformer (300W)

Component	Specification	NEC basis
Wire (copper)	12 AWG THHN	Table 310.16, 110.14(C)
Breaker	20A double-pole	240.4
Voltage	120V single-phase
Conduit (EMT)	1/2" EMT	Chapter 9 Table 4
GFCI	Required (GFCI breaker or device)	210.8(A)(3)
Max distance (3% VD)	361 ft at 120V copper	210.19(A) Note 4

Line-voltage outdoor circuit (20A)

Component	Specification	NEC basis
Wire (copper)	12 AWG THHN	Table 310.16, 110.14(C)
Breaker	20A double-pole	240.4
Voltage	120V single-phase
Conduit (EMT)	1/2" EMT	Chapter 9 Table 4
GFCI	Required (GFCI breaker or device)	210.8(A)(3)
Max distance (3% VD)	56 ft at 120V copper	210.19(A) Note 4

Installation notes

This project requires GFCI protection per NEC 210.8(A)(3). The simplest approach is a GFCI breaker at the panel, which protects the entire circuit. For 240V circuits, use a 2-pole GFCI breaker sized to match the circuit. GFCI breakers cost $40-80 depending on amperage.

Standard 120V circuits use NM-B cable with 12/2 cable (hot, neutral, ground). For conduit runs, pull individual 12 AWG THHN conductors. All connections must be made in accessible junction boxes.

Run length matters: every foot of wire adds voltage drop, reducing power to your equipment. The table below shows the exact voltage drop at common distances. If your run exceeds the 3% threshold, upsize one gauge.

Voltage drop by distance

Percentage voltage drop at common run lengths. NEC recommends 3% maximum for branch circuits and 5% for combined feeder plus branch.

Distance	12 AWG Co	10 AWG Co
25 ft	0.2%	0.1%
50 ft	0.4%	0.3%
75 ft	0.6%	0.4%
100 ft	0.8%	0.5%
150 ft	1.2%	0.8%
200 ft	1.6%	1.0%

Common products for 12 AWG Copper circuits

🧵Wire Roll12 AWG solid copper, 500ftCheck prices on Amazon (paid link) ⚡20A BreakerStandard pairing for 12 AWGCheck prices on Amazon (paid link) 🔌GFCI OutletRequired in kitchens, baths, garagesCheck prices on Amazon (paid link) 🔧Wire Strippers12 AWG compatibleCheck prices on Amazon (paid link)

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Detailed ampacity: 12 AWG copper. Wire size lookup: 20A circuit. Calculators: voltage drop · panel load calculator.

How NEC edition affects this project

Not every state uses the same NEC edition. The table below shows how requirements for this project differ depending on which edition your state has adopted. Find your state's edition here.

Requirement	NEC 2023	Earlier editions
GFCI for lighting	Outdoor lighting outlets now require GFCI per 210.8(A)(3)	GFCI only for outdoor receptacles, not lighting outlets
In-use covers	Extra-duty in-use covers required for all 15/20A outdoor outlets	Same as 2023

Currently, 17 states enforce NEC 2023, 21 use NEC 2020, 7 use NEC 2017, and 2 are still on NEC 2008. Three states (Arizona, Mississippi, Missouri) defer to local jurisdictions. Find your state to see which specific rules apply to your location.

Frequently asked questions

What wire size do I need for outdoor landscape lighting?

Use 12 AWG copper or 12 AWG aluminum on a 20A breaker at 120V. This is based on NEC 2023 Table 310.16 ampacity with 110.14(C) termination limits and 125% continuous load sizing per 210.19(A)(1).

Does outdoor landscape lighting require GFCI?

Yes. GFCI protection is required per NEC 210.8(A)(3).

Requirements vary by state. NEC edition, licensing, permits, and GFCI rules differ by jurisdiction. Check your state or pick it below for personalized info across WireRef.

Important: For reference only. Not a substitute for a licensed electrician. Electrical work can cause serious injury, death, fire, or property damage if performed incorrectly. Always hire a licensed electrician for electrical work, especially for service upgrades, panel work, and 240V circuits. Values are derived from NFPA 70 (NEC) for educational purposes. Always verify against your locally adopted NEC edition and amendments - local jurisdictions may enforce stricter requirements. WireRef provides reference information only and is not responsible for work performed based on this content. NEC® is a registered trademark of the National Fire Protection Association. Free NEC access via NFPA · OSHA Electrical Safety · Terms of use.

NEC 2023 references verified April 2026