Short answer: Article 411 covers lighting systems that run at no more than 30 volts ac or 60 volts dc, with lower limits where wet contact is likely (NEC 411.1). The system is either listed as a complete system or assembled from listed parts. Secondary conductors concealed in or run through walls, floors and ceilings use a Chapter 3 wiring method or another method the article allows, such as qualifying Class 2 wiring, it is kept away from pools, spas and fountains except where Article 680 allows it, and its supply branch circuit is rated not over 20 amperes. Article 402 covers fixture wires, the small conductors inside and connected to luminaires. Fixture wire is not smaller than 18 AWG (NEC 402.6), its ampacity comes from the fixture wire ampacity table (6 A for 18 AWG, 8 A for 16 AWG), and it is protected under the fixture wire tap rule, which allows 18 AWG up to 50 feet of run length on a 20-ampere circuit (NEC 240.5(B)(2)).
PSI lists Equipment and Devices (10 scored NEC Knowledge and 2 scored Calculations questions) and Wiring Methods and Materials (10 and 2) as subject areas of the Texas Journeyman exam. PSI does not name Articles 411 or 402 or say how many questions cover them. The Texas Journeyman Practice Pack has 1,000 original questions and 10 timed mock exams in the real two-part format, with step-by-step solutions for every calculation. Try free practice questions without signing up. Get the full pack for US$39 with one payment.
Tsai Electro is an independent learning site. Not affiliated with TDLR, PSI or NFPA. We explain the ideas in our own words and do not reproduce NEC text. Check every rule and table value in your own 2026 NEC, and follow your supervisor and the local inspector.
Where this fits
Receptacles, switches and luminaire installation are on NEC 404, 406 and 410. This page covers the two smaller articles that sit next to them: the low-voltage lighting systems used in landscapes, displays and cable lighting, and the fixture wires inside luminaires and their whips.
Article 411: low-voltage lighting systems
- Voltage. No more than 30 volts ac or 60 volts dc. Where wet contact is likely, the limits are lower (NEC 411.1).
- Listing. The system is listed as a complete system, or it is assembled from listed parts identified for the use: the power supply, luminaires, fittings and suitable secondary wiring.
- Power supply. The secondary is supplied from an isolating power supply, such as a listed low-voltage transformer, and the secondary circuit is generally not grounded. Check the article’s exception for a listed Class 2 power source identified for a grounded secondary.
- Where it cannot go. Secondary wiring concealed in or run through a building wall, floor or ceiling uses a Chapter 3 wiring method or another method the article allows, such as qualifying Class 2 wiring. The system is not installed within 10 feet of pools, spas, fountains or similar water features unless Article 680 permits it. In hazardous (classified) locations, the hazardous location articles control, so do not treat ordinary low-voltage lighting as suitable there.
- Branch circuit. The power supply is fed from a branch circuit rated not over 20 amperes.
Because the system is low voltage, it is easy to treat it as unregulated. Remember that low voltage does not remove the listing, location and supply circuit rules.
Article 402: fixture wires
- What they are. Fixture wires connect luminaires to the branch circuit conductors and run inside luminaires. They are not branch circuit conductors themselves, except where the article allows.
- Minimum size. 18 AWG, with narrow exceptions (NEC 402.6).
- Ampacity. From the fixture wire ampacity table:
| Fixture wire size | Ampacity |
|---|---|
| 18 AWG | 6 A |
| 16 AWG | 8 A |
| 14 AWG | 17 A |
| 12 AWG | 23 A |
| 10 AWG | 28 A |
- Overcurrent protection. Fixture wire is protected by the branch circuit overcurrent device when it meets the fixture wire tap conditions, which are listed by circuit rating (NEC 240.5(B)(2)):
| Branch circuit | Fixture wire allowed |
|---|---|
| 20 A | 18 AWG up to 50 feet of run length; 16 AWG up to 100 feet; 14 AWG and larger |
| 30 A | 14 AWG and larger |
| 40 A | 12 AWG and larger |
| 50 A | 12 AWG and larger |
Worked example: fixture wire on a 20-ampere circuit
A row of luminaires on a 20-ampere branch circuit is connected with fixture wire. The fixture wire run is 70 feet.
- 18 AWG? Allowed only up to 50 feet of run length on a 20-ampere circuit. 70 feet is too long.
- 16 AWG? Allowed up to 100 feet on a 20-ampere circuit. 70 feet is within the limit.
- Result. For this 70-foot run on a 20-ampere circuit, 16 AWG or larger meets the tap condition and 18 AWG does not. The connected load must also stay within the fixture wire ampacity, 8 A for 16 AWG, and the wire type must suit the use.
Worked example: landscape lighting supply
A homeowner wants a low-voltage landscape lighting transformer on a 30-ampere branch circuit.
- Branch circuit limit. The supply circuit for a low-voltage lighting system is rated not over 20 amperes.
- Result. Supply the power unit from a 20-ampere or smaller branch circuit.
Check yourself
- What is the smallest fixture wire size allowed? 18 AWG.
- What is the ampacity of 16 AWG fixture wire? 8 A.
- Can low-voltage lighting secondary wiring be run through a wall in any wiring you like? No. Use a Chapter 3 wiring method or another method the article allows, such as qualifying Class 2 wiring.
- On a 20-ampere circuit, how long can an 18 AWG fixture wire run be? Up to 50 feet of run length.
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Put the fixture wire numbers in one place
NFPA 70, National Electrical Code, 2026 Edition (softcover). Next to Article 402, write the page number of the fixture wire tap rule in 240.5, so the ampacity table and the overcurrent rule are one flip apart on exam day. The Texas exam is open book. PSI allows a soft-bound NEC with highlighting, underlining and notes made in advance. Loose-leaf, spiral-bound and ring-bound copies are not allowed, and only permanent index tabs made or supplied by the NEC publisher are permitted; homemade and third-party tabs are not.
FAQ
What voltage counts as low-voltage lighting under Article 411?
No more than 30 volts ac or 60 volts dc, with lower limits where wet contact is likely.
Does a low-voltage lighting system need to be listed?
Yes. Either the complete system is listed, or it is assembled from listed parts identified for the use.
What is the minimum size of fixture wire?
18 AWG, with narrow exceptions.
Can fixture wire be used as branch circuit wiring?
Generally no. Fixture wires connect luminaires to the branch circuit and run inside luminaires.
How long can 16 AWG fixture wire run on a 20-ampere circuit?
Up to 100 feet of run length.
Sources checked October 2026
- PSI Candidate Information Bulletin, Texas electrician examinations (updated September 15, 2026): https://test-takers.psiexams.com/api/content/bulletin/1682
- NFPA 70, National Electrical Code, 2026 Edition, Articles 240, 402, 410 and 411
