A look behind most homebuilt instrument panels will present a maze of electrical wires. Those wires may be neatly bundled or the view might resemble a rat’s nest of wiring mayhem. Every builder brings a unique combination of experience and skill to their panel wiring effort.
Heat-shrinkable tubular labels look good, but you must apply the label before you attach the terminal to the end of the wire. Having to use a heat gun for shrinking adds an extra step to the process.
One effort that is not wasted in organizing your wiring is to label the wires as they are being installed. Labeling is meant to provide a permanent identification of a wire near its connection end for the purpose of aiding in future troubleshooting. When an electrical component or instrument is replaced for service or upgrade, reconnecting the wires to their proper locations is crucial to making sure something does not get “toasted” in the process. You might fully understand where the wires are supposed to go—but will another person down the road that services your panel understand your wiring system?
There are a limited number of colors available for wires, and usually just a few of those are on hand in our personal stock. Even if you created a system of color codes (e.g., white is always ground, etc.) this standard would not necessarily be obvious to others. There are plenty of panels that use white for the color of nearly every wire! We just cannot count on wire color to help us trace those panel circuits.
Labeling a wire with a descriptive tag goes a long way toward the future maintenance of a panel. Identical labels should be attached to both ends of the same wire. The method used for labeling needs to meet four criteria: it must be easy, fast, permanent, and inexpensive. Wiring a panel is time consuming, and the added step of labeling wires as they are installed will be skipped if the effort becomes a burden.
The popular DYMO products work well—if industrial label stock is used. Shown is the LabelManager 160, which currently sells on Amazon for $14.39. Cartridges are sold separately.
One method that meets these criteria is the DYMO labeling system. The machines are available in various model incarnations ranging from consumer to industrial versions. The model we used, the LabelManager 160 (SKU: 1790415), currently sells on Amazon for $14.39. The label stock is contained in replaceable cartridges purchased separately.
The key to successful wire labeling is to not use the consumer grade label cartridge but rather the industrial grade versions of these cartridges (3/8″ label stock and tubular stock). These labels are designed for exactly the purpose we are using them—they will not fall off your wires!
Flat self-adhesive vinyl labels look almost as nice as heat-shrinkable tubular labels, but they are faster and easier to install. Just peel off the backing and apply the label lengthwise along the wire.
There are two styles of labels that can be used to label wires: the heat-shrinkable tubular label and the conventional flat self-adhesive label. While the heat-shrinkable tubular style appears to be the most elegant at first glance, once you realize that it must be attached prior to installing terminals onto the wire ends, it loses some appeal. Also, the extra step of having to use a heat gun for shrinking each piece will add to the effort.
My favorite is the conventional flat self-adhesive vinyl label. Type in a descriptive word(s) on the keypad and at the press of a button, the hand-held machine will output a set of your custom labels. Peel off the backing and apply the label lengthwise along the wire. This label stock is available in 3/8- and 1/2-inch widths. Since a majority of the wire I use behind the panel is in the 16-18 gauge range, the 3/8-inch width seems to work fine. You can choose the font size and style of the print to suit your needs. The time it takes to attach the flat labels is much quicker than the tubular variety—and the finished result is hard to tell apart. If your wires are really small—say 22 gauge or smaller—then the tubular labels may be desired as they cannot fall off (although they will not completely shrink to the tiny diameter).
The additional time spent making labels for your important panel circuits will be rewarded with not only a professional looking job—but will also go a long way toward the maintenance and safety of those expensive panel instruments down the road.
As the founder of HomebuiltHELP.com, Jon Croke has produced instructional videos for Experimental aircraft builders for over 10 years. He has built (and helped others build) over a dozen kit aircraft of all makes and models. Jon is a private pilot and currently owns and flies a Zenith Cruzer.