On the heels of last year's major update of our lighting module, we're excited to share some resources to inform new designers and seasoned professionals alike before they dig into our revamped lighting tools. Learn some primary lighting codes and ordinances, a few design guidelines and strategies, and a number of landscape specific techniques for creating and maintaining an effective and efficient lighting design.
Note: The following catalog of content covered in this webinar is time stamped to allow you to follow along or skip to sections of the video that are relevant to your questions. You can also search for content on this page using the FIND command in your browser (CTRL + F in Windows, Command + F in Mac OS.)
- Guidelines for Laying Out a Lighting System
- Lighting Techniques
- Color Changing LEDs
0:00 – 5:00: Intro/TOC
5:01 – 29:14: Codes
Low-voltage lighting and codes (5:08):
National Electric Code (NEC)
- Covers the basics of installation rules
- Is the base for all U.S. installations
- Also covers requirements for equipment
Local codes specific to your region
- Supercede NEC
- Different between municipalities
Dark/night sky ordinances
- Produced by local municipalities
- Range from lax to extremely strict
- UL, ETL, TUV
National electric code highlights (7:33)
- Defines low voltage as lighting systems that do not exceed 30 volts
- Wire can be direct burial wire (no conduit needed) as long as the wire is UF rated
- Wire needs to be buried a minimum of 6 inches deep and 24 inches deep under driveways and sidewalks
- Sets the max loads for wires
- Trunk lines cannot have an amp rating smaller than the transformer unless that wire is fused
Max amp per wire size (9:29)
Manufacture amp ratings for wire
10 ga = 30 amps
12 ga = 25 amps
14 ga = 20 amps
NEC amp ratings for wire
10 ga = 20 amps
12 ga = 16 amps
14 ga = 13 amps
Trunk lines amp rules (11:19)
Brian recommends having a fuse installed that matches the load in the field for a lighting system.
Local codes highlights (13:35):
- Specific for each location
- Will usually not be reviewed for permit
- Often vague and not up to date
- If you follow NEC, you should be covered
Product listings (14:23)
Agencies: ETL, UL, TUV
- All three are independent testing agencies that test products for safety
- Per NEC, all landscape lighting products must be “listed” with one of these agencies
- It’s manufacturers’ responsibility to make sure that their products are tested and up to date
Dark/night sky ordinances (15:47)
- Of all codes, this one has the most variations
- Often a product of an HOA or subcommittee
- Generally intended to reduce glare and light pollution
- Ideally, fixtures should have a “zero cutoff”
Zero cutoff (19:03)
Zero cutoff refers to a horizontal plane through which light from an installation cannot pass.
Examples of night lighting guidelines from moabhappenings.com (20:46)
Question: I prefer conduit to direct burial. Can you just pull the THHN type insulated, stranded wire instead of the UF cable? (21:40)
Answer: Yes, you can. If you’re worried about shovel kicks or otherwise want protection, that’s up to you. It’s just not needed if your installation is going into a more intimate space.
Brian’s thoughts on line voltage vs. low-voltage lighting (22:50)
Brian’s thoughts on reflective surfaces in regards to dark sky regulations (25:55)
Question: Have you heard of any restrictions regarding mounting transformers on homes? (28:11)
Answer: No, he has not.
29:15 – 39:44: Guidelines for Laying Out a Lighting System
How do I know what size transformer I need? (29:50)
NEC rule: A transformer can only be loaded to 80 percent of its capacity.
The 80-20 rule:
- Add 20 percent to total watts
- Reduce transformer by 80 percent
What is the longest wire run I can have? (34:23)
It depends on the load and the size of the wire.
For 12/2 wire:
- 40 watts will drop 1 volt in 100 feet.
- LED’s minimum operating voltage is 10 volts.
- In general, keep wire runs below 200 feet.
Definition of a volt amp (37:00)
- Watts = measure of real power
- Volt amp = measure of apparent power
- Volt amps are used for sizing wire and transformers.
Example of a spec sheet identifying volt amps (38:40)
Can’t find the volt amp spec? Multiply the watts by 1.5
39:45 – 52:09: Lighting Techniques
Trees and up-front lighting (front, cross, and back):
- Front-lighting: Eliminates shadows, minimizes texture, produces higher light levels, shows little detail
- Cross-lighting: Brings in shadows, adds texture, lower light level, enhances detail
- Back-lighting: Establishes depth, shows little details, few shadows, lower light levels
Use this technique on houses, trees, shrubs, walls, pillars, and fences.
- Eliminates shadows
- Downplays dimension of plants and shrubs
- Minimizes textures (depending on placement
- Produces higher light levels
- Shows little detail
Bullet lights and well lights, pros and cons (40:50)
Use this technique on rocks, fountains, tree canopies, and multi-trunk trees.
- Emphasizes shadows
- Adds texture
- Lower light level
- Enhances detail
Use this technique on trees, translucent leaves, and open/airy plants.
- Produces a halo effect
- Strengthens dimensions
- Establishes depth
- Provides sharp contrast
- Shows little detail
- Few shadows
- Little texture
- Lower light level
Rule of thumb: Match the number of up-lights to the number of down-lights.
Area/path lighting (46:24)
Don’t do path lighting unless you absolutely have to. Path lights are easily hit by extension cords, garden hoses, line trimmers, etc. If installing these types of lights, place them strategically – at least 12 to 18 inches off the path – and/or protect them with objects such as boulders. Avoid placing them in turf – and if you must, make sure they’re protected.
Step lighting (48:30)
Try to light steps without cutting into them. Place lights to the sides of the steps if possible.
Graze lighting (50:45)
- Enhances textures
- Adds contrast
Graze lighting reveals the surface and texture of any object. Typical applications would be to highlight flagstone, brick, or other rough surface material.
52:10 – 55:44: Color Changing LEDs
Brian recommends not using color to attempt to enhance a feature. Instead, he recommends working within the Kelvin temperature range – correlated color temperature (CCT):
- 10,000K: A very high CCT used in horticulture and aquarium applications.
- 6,000 – 6,500: A high CCT daylight source used to simulate average outdoor light conditions.
- 5,000K: Enhances blues and dull reds, and imparts a bluish tint to whites and greens. Used mainly in museums, jewelry stores, and hospitals.
- 3,700 – 4,000K: Neutral-colored light. Enhances colors equally without emphasizing yellow or blue. Used mainly in showrooms, bookstores, and office areas.
- 3,000 – 3,200: Most commonly used in homes but also in libraries, office areas, and retail stores.
- 2,700K: Used in restaurants, hotel lobbies, boutiques, and homes.
Example of 2,700K vs. 4,500K CCT (54:30)
55:45 – end: Resources
- National Fire Protection Association (NFPA) electrical solutions
- International Dark Sky Organization
- International Landscape Lighting Institute (ILLI)
- Unique Lighting Systems
Question: Night lighting looks best with “pools of light” in my opinion, but many municipalities require uniform lighting – especially on commercial projects. Is there a way around that? (57:20)
Answer: Not to Brian’s knowledge, unfortunately. He tends to emphasize the fact that he is designing the landscape lighting and suggest that the electrical engineer be put in charge of safety lighting.
Question: How does one decide what level of wattage or lumen is needed for a path or step situation? (58:23)
Answer: In general, you will be limited to the wattage of the fixture.
Question: Is there a code that exists for water features lighting? (59:20)
Answer: There is, and it’s changing as of webinar time. You will need to have a transformer that’s rated for water (although this requirement may have changed) and you will likely need to place that transformer a minimum distance from the water. You’ll also likely need water-rated fixtures.
Brian’s contact info:
- Email: firstname.lastname@example.org
- +1 480-381-6901