The Tale of Two Signs

When you produce channel letters as a custom electric sign shop or wholesaler, the first question you have to ask yourself is: “Where is this sign going?” A lot of sign manufacturers have a tendency to assume or think LEDs are a “one product fits all” for all applications, when nothing could be further from the truth.

When using Cold Cathode Fluorescent Lamps (CCFLs), a.k.a. neon, or Light Emitting Diodes (LEDs) to illuminate channel letters, each light source has its pros and cons. Like any other light source, attention to climate for light output has to be considered. LED light output drops in warmer ambient temperatures, and some products can fail in extreme zones such as Arizona and Las Vegas (where CCFL lamps would be the brightest).

In the cold areas of climate, LEDs will have the highest light output and longer life, while CCFL Hg Lamps will lose light output (unless on a 60ma system). The rise and fall of light output from both sources at the slightest change in ambient temperatures is accurately monitored in the various Light Project Comparisons on The Sign Syndicate (www.thesignsyndicate.com).
I live and work in San Diego, California. Any extreme-temperature days generally last only for short periods of time, so I have a good option of using LEDs without killing them.

It’s important to use the best light source for your sign application. To demonstrate, let’s look at one shopping center and one type of channel letter sign—yet two different light sources for two different purposes.

LED Sign
For one project in the NTC Shopping Center here in San Diego, using LEDs turned out to be the best choice. First this shopping center is composed of historic buildings, and the Design Committee is picky about holes being drilled into the old buildings (and rightfully so); so the fewest and smallest amount of wall penetrations was preferred. Second the stroke of the letters, by design, was too thin to accept components and allow proper clearances necessary for CCFL (neon) lamps.
LED modules. For their halo lighting, my client was very particular about a color of orange that I’d used for a CCFL-illuminated channel letter sign. One of the drawbacks about LEDs is that you’re limited with colors when it comes to standard modules. While we’re not far off from a standard Amber, I knew it would be too “yellow” for this client’s liking.
From experimenting with prior use, I chose YYZ Systems (www.yyzsystems.com) in Toronto, Canada. Marko from YYZ Systems looked at that set of Tangerine Orange letters I’d done in the past and proposed the use of a designer color from their ColorStroke product line. (Note: The ColorStroke uses an RGB LED from Nichia but, in this case, doesn’t use external controls to change the colors.) What they’ve done is identify about fifteen “designer” colors that are created by mixing the RGB diode and the resulting colors are permanently set at the module level.

Power supplies. When configuring a system, a shop has to match up components with one another; if not chosen correctly, this can lead to failure. Not every power source puts out exactly the 12 volts it might be rated for, and not every module can handle more.

Having tested different power sources from different manufacturers, I’ve seen them range from 12.02 to 12.51 volts. The smallest fraction of a volt can kill a LED system over time. While doing testing for our Light Project Comparisons, I’d unknowingly set a variable power source to 12.25 volts, and in one month, I had light degradation up to 13 percent—and those particular modules weren’t constant current.

The 12V model we used from Axiom Power Supplies (www.axiomled.com) can be adjusted from 10.5 volts to 16 volts on the output side. (Note: I primarily use these power sources for our Light Project Comparisons to make sure all products are on a level playing field and not to overdrive, unless specified otherwise.)
Wiring. In our reverse channel letters, we used a CL2 cable for our secondary wiring and a separate #14 AWG for grounding of the metal pan letter face back to the structural ground of the metal raceway used to house the power supply. Often companies overlook or assume that because a Class II LED system is low voltage, no grounding is required. NEC 600.7 requires all grounding and bonding of dead metal in signs, which has also been adopted by UL. Beginning 2011, Class II LED systems will be exempt.
You can make things easier if you find a 3-#14 AWG conductor CL2, so you don’t have a separate green wire for grounding. The thicker conductor helps with voltage loss with longer runs. A CL2 cable isn’t required to be in conduit (725.121 in the 2008 NEC Edition).

Reverse channel letters. For this particular job, the restaurant owners wanted a rustic copper look for their sign, so we decided to texture the letter faces and use metal paints and patina by Sculpt Nouveau (www.sculptnouveau.com). We had to time eight to ten minutes per face after applying a sulfur patina and then rinse away with water; otherwise the faces would get too dark. We painted the returns a satin bronze by Matthews Paint (www.matthewspaint.com) and the interior a satin white. For the reverse channel rear plastic, we used polycarbonate with frosted film applied to disperse the pinpoint LED light.
I had two choices: Mount the LEDs to the back of the metal pans or directly to the plastic. I did a quick mock-up with one letter in the shop and got a weird “Shard” appearance from the letter, which was the reflection off the outer plastic edges. Mounting the modules to the plastic and aiming the light into pans indirectly reflected back on the building wall and gave a softer and more evenly diffused light. But after looking at it for a while, this unexpected effect went well with the type style and the orange light. It gave the sign a “fire” appearance, so I stuck with it.

Power consumption. The end result: A very bright reverse channel letter sign with a custom LED system and a power consumption for each set of just 51.75 watts per sign. Running for 10 hours a day and 365 days a year, my client is paying $18.88 in annual energy costs.

Specialty CCFL-illuminated Sign
Shortly after doing this RGB LED-illuminated reverse channel letter sign, I received a call for a much larger sign from another tenant moving into the shopping center. One of the colors in their logo was blue, and there was a particular sign in my portfolio that caught their eye. The sign was illuminated by custom-coated rare earth and tri-phosphor CCFL (neon) lamps.
Initially I had to tell them that they weren’t going to be able to obtain the bright blue they wanted, because the shopping center only allowed LED-illuminated reverse channel letters. But LEDs are still lacking in bright light output in blues and greens compared to rare earth phosphor-coated CCFL lamps, so there was no way for me to duplicate the intensity of the CCFL lamps in LEDs.
It took some conversations, convincing, and submittals (and re-submittals) of design, but I came up with a way where the Design Committee would now accept this proposed sign illuminated with CCFL lamps. The installation would be the same amount of holes and size as an LED-installed sign; I just couldn’t exceed a three-inch-depth return.

Build and installation. My plan involved using Ventex CL electronic transformers inside each individual letter. Since they were reverse channel letters, I had to fabricate a bracket system to house the solid state transformers (SSTs). I had to keep them close to the inside of the metal pan and clear the way for the CCFL lamps to shine directly on the wall with no obstructions or shadows from any SSTs. I also had to make it easy for installation, grounding, bonding, and future service.

I planned my rear channel letter primary entry feeds around the CCFL lamp itself, dodging a situation where the primary feed can tough the secondary. I used a lot of extra polycarbonate tube supports to confine all secondary GTO from laying or touching any metal (the killer for these power sources).

By using SSTs to power the CCFL lamps, I only had to drill a single 1/2-inch hole to feed the 3/8-inch MC flex conduit that will feed the primary to each letter. On the end of each MC tail that connected to each polycarbonate rear, I used a 3/8-inch to 1/2-inch flex connector and a 1/2-by-2-inch conduit coupler. I sealed the exposed area between the letter and wall with clear silicone.
Then I used a simple 1/2-inch chase nipple to connect the letter rear to the coupler. By using 3/8-inch MC and drilling only a single 1/2-inch hole, I was able to have the CCFL process approved.

Power consumption. Using Elite Lamps’ (www.elitelamptech.com) custom-coated 12mm BAM Blue (Barium Aluminum Magnesiate) and 13mm Tri-Phosphor White (Elite 65D) CCFL lamps (or any other manufacturer’s equivalent glass), we have light output that is 30 to 50 percent brighter than standard conventional halo phosphate coated lamps. This blue halo lighting is three times brighter than anything I could’ve done in LED.

Going from a conventional transformer 24-26ma to 30ma RMS electronic transformers, the total power consumption for each sign is 260 watts on 84.75 feet of glass. That’s just a little over 2-1/2 100-watt incandescent lamps. Power consumption on a magnetic transformer would be nearly double, but it has to be noted that magnetic transformers make it possible for remote transformer installations (something you can’t do with SSTs).

The result: My client is paying about eighty-five dollars per year to light their sign ten hours a day.

Erik Gastelum owns West Coast Custom Signs in San Diego, California and moderates thesignsyndicate.com.

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