Is Your Cable Splice Right?

When you think about it, a cable splice is really the termination of two or more wires. And poor cable termination practices are the No. 1 technical problem for alarm system installation and service. Thus the need to discuss some time-proven cable splicing techniques.

I can’t think of a better subject to wrap up this year than installation workmanship and alarm circuit integrity.  Whether you are a newbie to the industry or a veteran, reviewing this subject never hurts. In fact, I would recommend this as a good discussion point for senior techs and tech management to review and reinforce the need for improved system reliability through diligent old-time craftsmanship. (I would like to hear from you managers, so E-mail me if you found this article handy.) Many of today’s young techs are very PC and IP savvy, but have not had the opportunity to learn some of the traditional tech skills that for years have made alarm systems reliable and dependable.

Wireless alarm systems and components have gained considerable popularity in recent years. They are easy and quick to install, have decent signal supervision, are lower in cost and have longer-lasting batteries. That said, a properly installed wired alarm system will always be more reliable and require less maintenance than a wireless system. So as with many technology decisions, by paying more upfront the customer can get a better quality wired system.

Remember, in a wired alarm system considerable importance is placed on an alarm circuit having excellent electrical continuity. A poor termination or cable splice can create high, and often intermittent, resistance that in turn leads to all sorts of technical problems. Many of you have heard the term “swingers,” but in this context they are not of the blonde or brunette variety (unless that is the color of your own hair being pulled out as you try to fix these annoying alarm system performance problems!). Why not save time, money and anxiety by making sure cables are connected properly in the first place?

Field-Proven Best Practices

There are times when you will need to splice cables, either solid or stranded, together. It might be a repair, running out of cable in a box, or a retrofit. Knowing what method of splicing can be critical for a good installation and system performance. Before getting into the specific types of splices, I will offer some general preferred practices based on my experience.

I make sure I have properly stripped back the appropriate amount of cable jacketing and insulation sleeve. I prefer wire strippers that have a die that fits the gauge of wire you are using. Make sure you pull the insulation apart and do not nick the solid wire as it can easily break now or even worse later with a change in temperature. A good tech will get the feel for when wire is properly stripped and will always double check for wire nicks.

Learn to twist your bare wires together with a wide 45° angle as this makes for a neat and tight wire twist. It will give extra strength to your splice. Practice traditional and proven wire splice twists such as the Western Union splice for butting two wires together. Becoming consistent and skilled with these practices will improve your splicing methods considerably. Oh yes, don’t forget the practice of “leaving a loop” of extra cable when you can. You never know when you may have to make another splice or connection.

3 Splice Types From Which to Select

The three most popular methods for cable splicing are the wire nut, B-Connectors and soldering/heat shrink (see photo).

The use of splicing wires with wire nuts is often found in high voltage (120VAC) work. However, I have found this practice extended by electricians to low-voltage work such as industrial controls. Fortunately it is rare, but I have found them used in alarm circuits. Wires are stripped, inserted in the wire nut cap-like device and the nut is twisted tight. It is a mechanical connection. This practice is the least preferred method to splice low-voltage wiring and should be avoided, especially for alarm work.

The next method, and most popular in the industry, is the use of B-Connectors. You will often hear these little colored gems called “chicklets” or “beanies.” They are applied with a crimping method and if done properly have proven to be as good as a soldered splice. Please note the emphasis on “done properly.” Call it the old-timer in me but I prefer not to take any risk and strip and twist wires when possible.

The three main suppliers in the industry — Dolphin, Elk and 3M — have shown that you do not need to strip the wire ends when making a splice, but I still do. These devices have small teeth inside and are designed to bite through the cable installation and make sufficient electrical connections. However, cable insulation material can vary. My concern is consistency of electrical performance over time. The industry does consider this a good method for cable splicing.

Making a viable splice with a B-Connector also requires proper crimping. I have seen everything used from plain pliers, the butt side of needle-nose pliers to dedicated ratcheting crimpers. If you want to crimp B-Connectors by the book then get the ratcheting crimpers recommended and often supplied by the B-Connector manufacturer. I personally prefer them too as they provide pressure consistency.  Also note gel-filled B-Connectors are available for damp environments.

Now, I have saved the best for last. Learning how to properly strip the insulation, twist the conductors, solder together and reinsulate with heat shrink tubing will make the best splice of all. Yes, this is old-school and will take extra time. But done properly, you know you have the best connection possible. With a little practice, preparation and methodology you can do these connections in a timely manner. Also, get in the practice of staggering your Western Union-type splices in multiconductor cabling so as to keep your overall profile very low.

Soldered splices are also the most low-profile and may often be the only way to pull spliced cable through conduit or wall spaces. Beanies can easily become caught and not fit in these conditions. You may also find the need for waterproof connections as in marine applications or below ground. Note that they make heat shrink tubing with adhesive lining for a better seal. To save on labor time they also make heat shrink tubing with an internal solder ring. In this case you can solder and shrink sealed tubing all in one step. Check out the Elektralink sealed solder butt splices at calcentron.com. For field installation, a butane micro torch is popular and inexpensive. You may want to select a professional micro torch unit such as the one suggested in this month’s Tool Tip.

Bob Dolph has served in various technical management and advisory positions in the security industry for 30+ years. To share tips and installation questions, E-mail Bob at [email protected] Check out his Tech Shack blog at www.securitysales.com/blog.


For field installation, a butane micro torch is popular and inexpensive. You may want to select a professional micro torch unit such as the one shown here.  Image courtesy Master Appliance Corp.Tech Talk Tool Tip

There are many low cost butane mini torches available. However, I have selected the type of torch that a pro installer should be proud to have in their kit. The UT-100Si Ultratorch kit from Master Appliance Corp. comes with all the parts needed for a professional solder/heat shrink splice. It is a flameless butane powered torch kit that comes with three Ultratip soldering tips, hot air tip, shrink attachment, hot knife, tip or torch ejectors, sponge, tool holder and spanner wrench. The company also provides repair service and parts if needed.


Tagged with: Bob Dolph Tech Talk

About the Author


Bob is currently a Security Sales & Integration "Tech Talk" columnist and a contributing technical writer. Bob installed his first DIY home intercom system at the age of 13, and formally started his technology career as a Navy communication electronics technician during the Vietnam War. He then attended the Milwaukee School of Engineering and went on to complete a Security Management program at Milwaukee Area Technical College. Since 1976, Bob has served in a variety of technical, training and project management positions with organizations such ADT, Rollins, National Guardian, Lockheed Martin, American Alarm Supply, Sonitrol and Ingersoll Rand. Early in his career, Bob started and operated his own alarm dealership. He has also served as treasurer of the Wisconsin Burglar and Fire Alarm Association and on Security Industry Association (SIA) standards committees. Bob also provides media and training consulting to the security industry.

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