Sign (C-45) · Lesson 3 of 7

Sign Lighting Power Limits (Energy Code Sec. 140.8)

"Sign Lighting Power Limits (Energy Code Sec. 140.8)" is lesson 3 of 7 in the Sign (C-45) Learning Hub. It opens with "Where Sign Lighting Is Regulated" and works through 6 short steps, then a worked example you can check yourself against.

Open the free trialSee pricing

One-time purchase, no subscription. Law & Business included.

Steps in this lesson

  1. Where Sign Lighting Is Regulated
  2. Name the Sign Type First (Section 100.1 Definitions)
  3. Internally Illuminated: 12 Watts per Square Foot
  4. Externally Illuminated: 2.3 Watts per Square Foot
  5. Unfiltered Neon and LED: Section 140.8(b) Efficiency
  6. Alterations and Relocations (Section 141.0(b)2M)

The worked example in the course applies this lesson to a realistic job in 6 steps, from "Cabinet sign type" through "Next year".

What you'll be able to do

  • Explain the main idea of "Sign Lighting Power Limits (Energy Code Sec. 140.8)" in plain language you can use on the exam.
  • Apply this step with confidence: "Internally Illuminated: 12 Watts per Square Foot".
  • Apply this step with confidence: "Externally Illuminated: 2.3 Watts per Square Foot".
  • Apply this step with confidence: "Unfiltered Neon and LED: Section 140.8(b) Efficiency".
  • Apply this step with confidence: "Alterations and Relocations (Section 141.0(b)2M)".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Sign Lighting Power Limits (Energy Code 140.8)CABINET SIGN10 ft x 4 ft, one faceInternally lit: 12 W per sq ft40 sq ft x 12 = 480 W maxWALL SIGN, 60 sq ft litExternally lit: 2.3 W per sq ft60 sq ft x 2.3 = 138 W maxMaximum allowed lighting power(a)1 Internal: sign area x 12 W/sq ftCabinet 10 x 4 = 40 sq ft (one face only)40 x 12 = 480 W allowedProposed 520 W is over 480 W: fails(a)2 External: lit area x 2.3 W/sq ft60 sq ft x 2.3 = 138 W allowedThree 40 W lamps = 120 W: passesFour 40 W lamps = 160 W: fails(b) Unfiltered neon and LEDNeon: 75% (under 50 mA), 68% (50 mA up)LED power supply: 80% or greaterAllowed power = sign area x W per sq ft: 480 W internal, 138 W externalTrim the 520 W cabinet to 480 W or less; use three 40 W lamps, not fourDouble-faced signs count one face only; only unobstructed lit area counts on an externally lit sign2025 Energy Code Sec. 140.8(a), (b); Sec. 100.1 (definitions); Sec. 141.0(b)2M (alterations)CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: Where Sign Lighting Is Regulated

The 2025 California Energy Code, Part 6, Section 100.0(e)6 says Sections 130.0, 130.3 and 140.8 apply to newly constructed signs located indoors or outdoors, and Section 141.0 applies to sign alterations (Table 100.0-A has the same Signs row). Section 140.8 'applies to all internally illuminated and externally illuminated signs, unfiltered light emitting diodes (LEDs) and unfiltered neon, both indoor and outdoor', and each sign must comply with either Subsection (a) or (b), as applicable. Three exceptions: unfiltered incandescent lamps that are not part of an electronic message center, an internally illuminated sign or an externally illuminated sign; exit signs; and traffic signs (the last two follow the appliance efficiency regulations).

Step 2: Name the Sign Type First (Section 100.1 Definitions)

Section 140.8 sorts signs by how they are lit, so use the Energy Code's own definitions. An Internally Illuminated Sign has a light source inside it and a luminous message area, including cabinet signs and channel letter signs. An Externally Illuminated Sign is lit by a light source outside the sign directed at its face. An Unfiltered Sign is one where the viewer sees the light source directly with no colored filter, including neon, cold cathode and LED signs. A Double-Faced Sign has two parallel opposing faces, and the Illuminated Face is the side that carries the message.

The remaining 4 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

More lessons for this trade

Browse all lesson previews

Ready to practice for real?

Try the real classroom free, no sign-up, or get the full course for your trade.

Open the free trialSee pricing

Independent exam preparation. Contractors Classroom is not affiliated with the Contractors State License Board, and no course can guarantee a passing result.