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Electric Signs

10 Pitfalls With Channel Letters

Remember these simple tips and improve the look of your channel letters



Channel Letters, especially those in the shopping mall environment, are often fabricated to cover-up mediocre neon bending. Some of the problem is in the design of the sign. Bids are sent out to get prices without sufficient data to make and install a functional letter. Prices are sent anyway, and work-a-rounds are often created on site. Just to avoid any possible comments the premier issue with channel letters is the Listing requirement. This will be a topic for another issue. National Electrical Code (NEC) Article 600-4: Listing Required. Every electric sign of any type, fixed or portable, shall be listed and installed in conformance with that listing, unless otherwise permitted by special permission. 1. Clearance The shape of the letter itself dictates how the neon goes inside. For safe operation, the codes have spelled out what cubic volume is required around the tube itself. This is commonly in the form of a table equating a distance to a voltage level. It is obvious that the higher the voltage level the greater the distance to grounded metal required. Note that it is the metal (grounded or otherwise) that interacts with the electrical field. NEC 600-34(b) . . . shall be separated from grounded metal and combustible material by noncombustible, nonabsorbent insulating material or be supported so as to maintain a separation of not less than 1 1/2 in. between conductors or between conductors and any grounded metal. 2. Grounding Proper grounding is not a science, but too many sets of neon letters do not have it right (improper connectors, excessive lengths of flexible conduit and transformers that are simply set into the transformer boxes). Unfortunately the code does not take into consideration the fact that traditional neon transformers do not "shut off" when the secondary shorts to ground. The function of the ground in primary power connections is to facilitate the operation of the circuit protection. The ground may even become a detriment in the secondary neon circuit. It should be noted that some countries have or are looking at eliminating metal conduit (ie, grounded metal conduit) from neon circuits. 3. Splices Although it is often considered as acceptable simply "because it’s been done that way for years," a twisted splice may not meet the code. Note that the NEC does not say "twisted wire" anywhere. The norm for electrical work is: NEC 600-34 . . . mechanically and electrically secure. This would equate to some sort of device in other aspects of electrical work. The reason wire nuts were invented was to eliminate the tedious work of twisting soldering, and wrapping that once was common in circuit wiring. The room for complications in completing a "twisted-wire splice" per the specs makes mechanical connectors look like a bargain. A "twisted wire splice," if acceptable, still requires insulation. A twisted splice is often looked at as functional and less expensive than housings. The cost of labor is frequently a factor in how a product is constructed. Reducing a known cost, like materials, is routinely used as a method to compete on price. The reality is usually realized in utilizing labor-saving devices. They can control the unknown costs. 4. Insulation There are no bypasses in the code for insulation. The last decade has shown that the new methods of plastic production have created several types of high quality wire. The problem in channel letters is not always the wire’s insulation, but that of the splice. For several years now the NEC MO-34 (d) has required All electric-discharge tubing terminals shall be insulated with a material suitable for the voltage and environmental conditions expected. There are many types of sleeves and boots being used that do not fit "environmental conditions." Long term, they fail. Electrical tape has been utilized as an insulator for many electrical functions. But with electrode connections, tape as an installation device has little functionality and plenty of room for human error. There are several top quality insulating devices on the market that will fit the bill. Even with these parameters, there is a chance for excessive modifications, leaving the product semi-functional. For now, it appears that glass, long term, holds the most credence. 5. Competent Bending The discussion of insulation, twisted wires and clearance could possibly be summed up into one category: competent bending. One of the reasons that there are clearance problems is the poor level of control expressed by some tube benders. This leaves the installer with an insurmountable problem: Scholck’s First Theorem: The lower the cost, the greater potential for problems. Unfortunately this leads to our next topic: serviceability. Sometimes, it seems that "twisted wire" connections are a "must" as "too much control" is required to bend a tube that fits into glass housings (even though there are several types on the market that could be considered adjustable or at least forgiving). There is no shortage of housings or housing styles, although I can think of several refinements that would create efficient, safe products. Those who use glass electrode receptacles create superior products in several categories. 6. Serviceability During the 1970s, neon channel letters were gaining popularity despite a reputation for being expensive, long term. This unfortunately is a concern that many end users do not understand. Years of service and installation have shown that opening a letter, untwisting wire ties and pulling a tube from its sockets is vastly superior to any other form. I can remember using a mirror for one job, because the letters were assembled and pushed into/onto the wall "never to be removed." I knew that I would be back because I was unable to make a proper reconnection when a lamp was serviced. The lesson: Always design letters so they can be serviced later. It’s cheaper for the customer and saves on maintenance. 7. Weatherability Several components have not shown their long term viability for use in channel letters, including backing materials in which the screw holes elongate and faces pull lose, gaskets that do not keep the environment out (as required), or adhesive bonds that fail from long term ultraviolet (UV) exposure. Unfortunately, the products are often quite legitimate. The room for improper treatment, assembly or utilization leaves too much room for error. There will be exposure to other damaging forces as well. You must design to limit the impact of small creatures as much as the impact of rain. Open-backed letters have long held a special place in the hearts of bird watchers everywhere. They provide warm, out-of-the-way places in even the biggest of cities. (I have seen many a great bug collection started this way also). 8. Cold-Weather Operation Although enclosed in channels of metal and plastic, the neon in exterior channel letters lives in almost the same environment as an exposed tube. The neon tubes routinely fail to adequately illuminate in a cold environment. There are several solutions: clear tubes, different colors, and even incandescent lamps. Incandescents burn bright in any weather and have been utilized as a heat source. In large scale letters, they warm the interior environment of the channel letter. 9. Visibility This is a subjective rating when applied to channel letters. Script letters in face-lit situations look better when viewed off-center than the same copy reverse lit. Blue is a poor color choice because of the way we as humans view it. This is not as important indoors where, there is additional ambient light. Several other colors and combinations require greater lumens to create a good appearance. They often end up looking poor when constructed in a standard manner. In a recent sign design, there was four times the light in a defined space. This was imperative to obtain a good look for a royal blue and forest green logo. Imagine some letters with four times as many tubes! 10. Installation One thing that often kills a good letter design is the installation. Although the visual look is maintained, there are many obstacles that create hazards only "gerry rigging" will overcome. One recent fire scene looked as though several building members were involved right at the point of conflagration. The installer modified the design and eliminated proper conduit connections to keep from drilling through the obstruction. The installation had worked for a while. Unfortunately the building relied heavily on wood construction. Give an arcing neon letter enough time and . . . who knows. Field inspections and prefabrication are the only methods that catch problems firsthand. Poor building design and quick refurbishes to convert a store over leave the sign installer with a bunch of headaches. Conditional installations are the one way to go into the unknown. Hit an obstruction, back to the shop rework and re-bend till it is correctly installed. Costs are passed on to the end user.



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