One of the most nettlesome areas of boating electronics is making dependable wire connections that will last for years. Because marine elements are conspiring against you, special care is necessary to achieve long-lasting connections.
One of the most common problems is using improper tools and terminals-pliers as crimpers, or junk tools, with worthless pot-metal terminals; or attempting to solder terminals because you heard it was the best way to go. In most cases, it is neither necessary nor desirable to solder, as well explain later. The last problem is the fault of manufacturers who feel they do not need to supply detailed installation instructions. We all know that there is lots of gear installed by do-it-yourselfers, who will have to toil through often poorly translated or abbreviated instructions. Sometimes its even difficult for the pros to figure out the manual.
We don’t want to cry too much in our beer here, and a little knowledge and understanding can go a long way in making your next installation successful and lasting. Its possible to get a decent set of crimpers for minimal expense, but you must be very selective. One thing you should not scrimp on is terminals. Be sure to select only quality, brand-name (e.g., Ancor) terminals which have a UL listing. Twenty for a dollar, grab-bag stuff is just false economy. The metals used in cheaper terminals are not as corrosion resistant, and often create more resistance than good terminals. Look for brand names, such as AMP, T&B, and Amphenol, to name the big players. Then make sure the insulator color coding of red, blue, or yellow is there. Sometimes, terminals are made for special uses and require special tools because the dimensions do not match standard tools. Normally, these specialized terminals have stripes or other colors to indicate they are non-standard.
For the basic DC low-voltage connection with insulated terminals for 10 to 22 gauge wire, the best way to do this is with proper crimpers.
The two most common styles of crimpers are ratcheting and non-ratcheting. They both have merit. Ratcheting crimpers are best on the bench, as they can be more difficult to operate with one hand. They use a compound leverage action that needs less hand pressure, but a longer handle stroke. They will not release until the proper crimp force is achieved. They are generally more consistent and precise, and provide the best crimps. They make a double crimp, i.e., both the metal barrel and insulation sleeve are crimped at once. A separate wire stripper will be needed to prepare the wire. Non-ratcheting crimpers, on the other hand, are the cheapest approach. They rely on your hand strength for proper crimp pressure, and can be tiring to use for more than a few crimps. A weak or tired hand can make a weak crimp, but they are the easiest to handle in cramped quarters, and almost always have several other functions such as wire strippers or cutters.
Junk crimpers present a number of problems. Cheap steel jaws can bend under crimping pressure and tend to develop an increased gap in the jaws. Poor crimpers also have very thin steel, giving a less than satisfactory crimp surface area. (A properly crimped terminal is actually a cold weld in which the wire and terminal nearly fuse at their mating surfaces). Lastly, the jaws of junk crimpers tend to deflect sideways under pressure due to a poor or loose pivot pin, as well as the weakness of the steel. This can result in torn insulation and improper crimp pressure.
For situations requiring larger terminals (for wire size 8 gauge or larger), a different approach is necessary. The pros use large, long-handled crimpers with dies for the various sizes. These, however, cost hundreds of dollars. We tested two low-cost alternatives costing about $25 each. They require a good size hammer blow and do work-sort of. One thing you absolutely do not want to use, other than in an emergency and then only temporarily, are battery terminals that attach to the stranded battery cable with bolts and nuts. This method does not apply enough pressure for a proper crimp, and are very difficult to seal, inviting rapid corrosion.
Strippers Weve Known
Though wire strippers are part of non-ratcheting crimpers, a case can be made for a dedicated wire stripper in all situations. First, consumer models are cheap, costing from $3 to $20. The better ones tend to be far more precise, and thus less likely to nick wires while stripping them. There are several designs available, some of which are really handy and fast for stripping wire in awkward places without yanking on the wire. Other designs virtually guarantee nick-free stripping. Also, strippers that have AWG printed on them are designed for solid core wire (which is slightly smaller in diameter than the stranded equivalent). This means you may have to use the next larger size hole to avoid any nicks to stranded wire. Some strippers are available for just stranded wire and are so labeled.
Often we hear so-called experts tell us to be sure to solder all connections; this is rubbish. With the advent of decent, low-cost crimpers, there is simply no good reason to make life any harder than necessary. Soldering requires the Goldilocks approach to make good joints-not too hot to melt insulation, not too cold to cause a poor connection, but just right for a good joint; in other words, practice. Worse yet, soldering makes for brittle joints, which is the last thing you need in a vibrating environment. Because of the high failure potential, ABYC specifically recommends against a soldered joint as the sole means for a mechanical connection
We are primarily interested in insulated terminals, as their use constitutes the vast majority of all connections made by boaters. They most commonly come in three color-coded and usually marked sizes: red for 18-22 gauge wire, blue for 14-16 gauge, and yellow for 10 to 12 gauge. Larger- size insulated terminals are available, but require alternative crimping methods as mentioned above. Tinned copper is a good choice for electrical conduction, formability, and corrosion resistance. There are several ways to provide mechanical strength and/or weather resistance, but electrical tape is not a good choice.
If you want to use a tape-type material, use a self-fusing silicone tape that cold fuses to itself as you wrap,then stretch and tighten it around itself and the joint. The big advantage is that there are no additional tools required to accomplish this. There are other methods that are more weather resistant, however, such as heat shrink tubing. The tube is slid over the joint (or up to the terminal eye) and then shrunk by the addition of heat from a heat gun, available for as little as $20 (a hair drier is not hot enough). The advantage is not only superior weather resistance, but also a dramatic improvement in mechanical strength. Some people use lighters with varying degrees of success, but it can be downright dangerous to use an open flame, so we cannot recommend it.
An even more weatherproof and secure terminal is also available, but at a premium price. This terminal has the heat shrink tubing right on the terminal, and the inside of the tubing is coated with a heat-activated sealant. Separate sealant-impregnated heat shrink tubing is also available at a premium price. Sealant-impregnated terminals may be more than you need except for exposed conditions. Another method is to coat the terminal with a liquid electrical tape, which does help with corrosion resistance but does little mechanically. An approach that helps with corrosion resistance between contact surfaces is a highly conductive copper-based paste applied when connecting terminals (We used KopprrShield from Thomas Betts, about $10).
What We Tested
We tested a cross-section of crimpers from $5 to$54, along with a few wire strippers from $3 to $20. We crimped a number of terminals of all sizes accommodated by each crimper. We noted ease of use, quirks, adjustability, if any, and the surface area of the crimp. We checked for any damage to the insulation, distortion or any other signs of a bad crimp. We then tested how well the crimp held up to a steady tug on the terminated wire against a pull scale, using the same brand terminals with each crimper for each test to reduce the effect of terminal variations among brands. We also tested any built-in wire strippers for accuracy.
We tested stand-alone wire strippers by stripping wires of each size handled by each stripper. We checked for ease of stripping, accuracy (i.e., no nicking of wire), as well as any special features that a stripper had, such as automatic wire sizing, speed of use, one-hand operation, and so on.
We also tested three unofficial terminal classes: grab-bag specials of unknown origin, which are extremely common; brand-name insulated terminals with additional metal support extending into the insulated sleeve for a better mechanical connection; and special marine terminals, with heat shrink insulation attached, and impregnated with a heat- activated sealant. All were crimped with our best scoring, ratcheting crimper. These crimped terminals received three tests.
First, we spun them on an electric drill in such a way as to not twist the wire, but only subject it to wagging back and forth over a 6″ arc against a wood surface. Next we pulled on the wire that was attached to a pull scale to see at what pound pull the wire would pull out of the terminal. Lastly, the terminals received a three-week bath in highly concentrated saltwater. Resistance was checked using a calibrated Fluke 870 graphical multimeter, before and after the salt bath, both without current and with a 10-amp load. The addition of the load was designed to check if there was any partial corrosion which would not necessarily be detectable without a high current through the wire, since resistance without a load would not change if even one strand of wire made contact.
At the low voltages and higher currents found in boats, very small increases in resistance caused by corrosion have a significant impact on the current-carrying capacity of a given wire/terminal combination. If enough corrosion occurs, the wire could heat up to the point of causing a fire.
What We Found
The best performing ratcheting crimper is the Ancor. The most important feature of this crimper is the contour of matching crimp faces, which are significantly different than either of the other two models in this class. The Ancor has a double crimp design (as do the others), but they are formed to give a much greater surface area to the crimp. This translates into both strength and corrosion resistance. The Ancor does not have a pressure adjustment function, which in a high-volume situation would be necessary, but not so for individual use. The jaws are not symmetrical, so you will have to be careful to properly load the terminal, as it will crimp backwards as well, but not satisfactorily.
The Ideal Crimpmaster, our most expensive test model at the consumer level for which we are testing, appeared to be slightly more ruggedly designed, and had a crimp pressure adjustment to compensate for wear over time. The crimp surface area was less than the Ancor, but still did a good job. These jaws were also asymmetrical, so care to place the terminal in properly was required here as well.
The cheapest model, a generic brand, sold by a variety of electronics catalogs had the least acceptable jaw design, yielding a bad crimp with minimal surface area for this class of tool (though more than the non-ratcheting models). A manufacturing flaw, however, made this crimper a failure. The opposing jaw surfaces engaged before the proper crimp force was completed, causing a very weak crimp that looked OK until you tugged on it.
Is a ratcheting crimper for you? For the casual user, probably not, unless hand strength or other problems (Carpal Tunnel syndrome, for example) are present. Remember, these are primarily bench tools. They were very awkward in close quarters because the long-travel, ratcheting mechanism requires two successive hand placements (when the wire can slip out) to complete the cycle.
The ubiquitous non-ratcheting crimpers have the advantage of ease of use in tight spaces, and additional functions such as stripping wire (although only marginally acceptable due to mediocre alignment in all models). The crimp surface area is much narrower, and you will have to crimp the terminal and sleeve separately for a double crimp (no big deal).
In this class, there was no competition. The cheapest-but not by much-models exhibited all the bad traits of junk: weak steel, poor alignment, etc. The Seven Seas model, picked up at a marine chandlery, actually was better at cutting terminals than crimping. The GB tool, said to handle both insulated and non-insulated terminals, is best left for non-insulated only. For only $10.10, the AMP Super Champ was just that, a real champ that will last for many years, if you keep a bit of anti-corrosion lube on it.
In our torture tests, 16-gauge wire pulled from the terminal at 65 lbs. of pull with the AMP Super Champ, a substantial level. With the Ancor and Ideal ratchet models, we pegged 100 lbs. with no pullout. In the drill motor test, in which we spun a chucked butt splice on a 12″ wire for five minutes at 1300 rpm, the ratchet-crimped terminals showed no ill effects. With the AMP Super Champ single crimped terminal, the wire pulled out with less than 5 lbs. after testing. The wire had failed due to the concentrated flexing right at the crimp. The addition of heat shrink in the next test distributed the flexing better, and the crimp held up.
In our terminal corrosion test, there were virtually no changes in resistance after immersion. With the maximum current loading test, it was a different story. In this mode, the entire wire capacity was tested, so even a small amount of corrosion would be detectable as a voltage drop. Even after three weeks in saltwater the Ancor terminal with sealant impregnated heat shrink came through with no voltage drop. The other test wires had from a 5%to 10% loss from their preliminary readings.
We decided to continue our corrosion test, adding a fair amount of salt to the system to see if we could speed up the process of deterioration. Even we were surprised when, after 10 more days, we found the non-sealed terminals had admitted enough salt solution to turn the wires green and form salt crystals several inches along the line. Although this was an extreme exposure test, we can deduce that, eventually, crimps that leak will corrode and fail.
Does this mean that the Ancor terminals and ratcheting crimpers are the only way to go? Not at all, especially considering their high price. What it does suggest is that under particularly adverse conditions of constant weather exposure and vibration, terminals of this type should be given serious consideration, or at least some additional weatherproofing and vibration-resisting alternative.
Only one wire stripper tested-the Miller economy model-is not recommended. It employs an adjustment screw to prevent overcutting the wire, but we know that most folks will not take the time to adjust the tool each time they cut a different size wire. The result will be nicked and cut wire. Spend a few bucks more for one with positive stops or separate cutting surfaces or a sensor mechanism for different wire sizes.
The Ancor had the extra functions of pliers on the top of the cutter (very handy) and very precise cutting surfaces that made stripping a pleasure. The Buchanan Ultimate Stripper was fast, accurate, required no adjustments for a wide variety of sizes, and allowed one-handed stripping (great for tight spaces). The entire tool, except for the cutter blades, is corrosion proof. We got ours at Home Depot.
Crimping Large Wire
Terminal sizes #8 and larger present a new problem. They are too big to handle with normal consumer crimpers. The pro stuff costs several hundred dollars, so enter the smashers. We tested two different approaches, both of which required the services of a stout hammer (2-lb. preferred) for crimping force. We liked the unit from McMaster but were not as sanguine about the model from Ancor, which put an awfully small crimp in our test terminals. The McMaster was more ruggedly built, and had a much greater useful range from #14 to 4/0 size terminals. We cannot unequivocally recommend the McMaster, however, as we found a #2 terminal to be the reasonable size limit of dependable crimping (such as for a large inverter installation). Larger sizes would probably be best done by the pros, except in emergencies or temporary situations. Lastly, be sure to use finely stranded, very flexible wire, which has the greatest formability with these tools.
A good, serviceable crimp can be made with the AMP Super Champ non-ratcheting crimper, available for only $10.
All crimps can be made significantly stronger and weather-resistant with the use of heat shrink tubing or self-fusing silicone tape.
Junk crimpers are terrible and should be avoided.
Hammer-type crimpers for larger terminals are usable, and we recommend the McMaster model if your needs go up to size #2 terminals. Leave larger terminals to the pros.
Integrated, heat shrink/sealant-impregnated terminals proved to be superior in corrosion resistance in our torture test, but only marginally better over normal heat shrink.
To properly activate heat shrink tubing, 120-volt power and a heat gun is required. Self-fusing silicone tape is your second best bet. Liquid tape is a third, less desirable, choice.
We loved the Buchanan auto wire stripper. The Ancor stripper also did an excellent job, with pliers and cutters as an added bonus.
Contacts- AMP Super Champ, Contact East, 335 Willow St., N. Andover, MA 01845; 508/682-2000. Ancor Co, 501 Aaron St., Cotati, CA 94931; 707/792-0132. Buchanan Construction Products, 101 Bilby Rd., Hackettstown, N.J. 07840; 908/850-5200. GB Electrical; 6101 N. Baker Rd., Milwaukee, WI 53209; 800/822-9220. GC Thorsen,1801 Morgan St., Rockford, IL 61102; 815/968-9661. Ideal Industries, Becker Pl., Sycamore, IL 60178; 815/895-5181. Radio Shack, 1500 One Tandy Ctr., Ft. Worth, TX 76102; 800/843-7422. Ripley Co/Miller Div.,46 Nooks Hill, Cromwell, CT 06416; 203/635-2200. Seven Seas Marine, Manset Marine, 50 New County Rd., Rockland, ME 04841; 800/322-6500. McMaster-Carr Supply Co., Box 440, Bruswick, NJ 08903; 732/329-3200.