CABLE ASSEMBLIES AND WIRE HARNESSES, the words are used all the time and often interchangeably.  One person’s cable assembly is another person’s wire harness.  Is there a difference, and if so does it really matter?  This article will show how to tell the difference, and give pros and cons for each.

Why would it matter what a bunch of wires is called?  Let’s use an example we can all relate to – food.  Most likely all of us have seen something on a menu at a restaurant and didn’t know what is was, and usually we ask someone at the table with us or the waiter.  But what if we didn’t and ordered noodles expecting pasta?  They look the same, but don’t really taste the same.  Or say we order tuna, expecting sushi, but we are served tuna salad instead.  Both are fish, but are decidedly different.  The same is true with cable assemblies and wire harnesses; while they both have wire they are decidedly different.

A cable, which is used to make a cable assembly, is a grouping of wires that are covered by an extruded sheathing.  Typical this sheathing is a thermoplastic such as polyvinylchloride, thermoplastic rubber or polyurethane.  In some special instances a thermoset material such as chlorinated polyethylene, chlorosulfonated polyethylene or EPDM hydrocarbon rubber.  Whether thermoplastic or thermoset material is used the key is the individual conductors are covered by a compound extruded around them.  This layer is in addition to the insulation on the individual wires providing additional protection from heat, moisture, abrasion, compression and other hazards the cable assembly might experience.

A wire, or conductor, which is used to make a wire harness, is an individual strand or group of strands covered by an extruded sheathing.  Again, this sheathing can be thermoplastic or thermoset, however in the case it is just a single layer.  When wire harnesses are made a group of individual wires are assembled together and typical “bound” in place with a mechanical device such as a cable tie, heat shrink, tubing or woven braiding.  Since the wires have only the one layer of sheathing the amount of protection from the environment is much less.

So what are the pros and cons of a cable assembly?  Some pros include, as mentioned above, increased protection from the environment due to the extra layer of plastic.  Also, having all the conductors in one bundle makes a neater and more convenient package which can be quite useful if the cable must be routed through or around equipment or components.  Having a cable also can allow the connectors on the end to be over molded, thus sealing the entire cable from the environment.  Two cons are an increase in size and weight, and typically the cost is higher due to the extra material and labor.

And the pros and cons of a wire harness?  These are usually the opposite of cable assemblies.  Pros include smaller size and weight, and lower cost since the extra material and labor is not used.  The cons are an increase in environmental vulnerability since the individual wires are exposed and the possibility of the wires “catching” on items during installation.

Since the differences are quite apparent what are some typical places each are used?  Cable assemblies are found in many exposed uses such as medical devices, industrial controls, military electronics and security products.  Wire harnesses are most often found inside products such as computers, vehicles, control cabinets and electronic assemblies.  So much like ordering food, when designing or buying a cable assembly or wire harness it is critical to know what you want.

Dear Colleagues,

I wanted to share a nice article about Meridian Cable’s customer Cross Match and their product, SEEK. The article discusses how the U.S. military probably used DNA and the SEEK to verify bin Laden’s identity.  Congratulations to Cross Match, it is nice when one of our customers ends up in the headlines as a result of assisting in such a huge capture.

CSI bin Laden: Commandos Use Thumb, Eye Scans to Track Terrorists

http://www.wired.com/dangerroom/2011/05/csi-bin-laden-commandos-use-thumb-eye-scans-to-track-terrorists/

Here is an excerpt:

But according to a senior Defense Department official, chances are they used the tool pictured above to verify his biometric information. The device is called a Secure Electronic Enrollment Kit, or SEEK, a handheld biometrics recorder that takes iris scans, fingerprints and facial scans and ports them back to an FBI database in West Virginia in seconds.

“We’ve always said this is about more than finding people in a crowd,” said the senior defense official, who requested anonymity to talk about the CSI-like gear that Special Operations Forces carry. The latest version, developed by a company called Crossmatch, is known as SEEK II, and it came out last year. It weighs less than 4 pounds, and its ability to send information back to the FBI database is “wham-bam,” even from low-connectivity areas.

Meridian Cable is proud that a custom cable assembly we designed and built could be a part of something this monumental.  We would also like to thank all the troops, military and government personnel who took part in this action, and are eternally grateful for their dedication and hard work on behalf our country.

Best regards,

Bud Kinzalow

President

Meridian Cable

If you are not familiar with the industry, coil cords and cable assemblies are items easily looked over and taken for granted.  You might not realize just how prevalent they are and how much of a part of daily life they encompass. If you stop to take a look around you, coil cords and cable assemblies are everywhere.  Due to their unique applications and locations, the standard coil cord and cable assembly are no longer “enough”. There is a growing need for “custom” coil cords and cable assemblies to accommodate the ever changing world and environment we live and participate in on a daily basis.

What are some of these unique applications and locations that a custom cable manufacturer may be able to provide solutions to a customer? They can include, but are not limited to: medical devices and operational equipment, surveying equipment (for which UV inhibitors and special materials can be used to make the coil cords and cable assemblies weather and animal proof), security devices, and operational assistants in daily activities.

Where can one see these coil cords and cable assemblies in action and being used in practical day to day applications? A few of these can be found at big box retailers, in hospitals, on construction sites just to name a few. If one were to look close enough, they would find coil cords and cable assemblies to be everywhere.

When is a custom manufacturer the one for you? A custom manufacturer can offer a more personalized approach to answering your specific application and need. Not all coil cord and cable assembly needs are the same nor are they a standard size. A custom manufacturer can evaluate your need, environment and individual solution and, with their team of engineers, can create a product that will offer you a customized solution to answer your specific need.

While this is just a generalized overview to explain the benefits of seeking out a custom coil cord manufacturer, please feel free to contact one of the experienced team members at Meridian Cable to answer your custom coil cord and cable assembly questions.

Emily Mierzejewski

Customer Manager

 Meridian Cable

Anyone who has used an electronic device has come in contact with a strain relieved wire or cable.  Some strain reliefs are visible and some aren’t, but all of them are vital to the life of an assembly using wire or cable.  This article will explain the reasons why strain reliefs are needed and the basic types and methods used.

Why use a strain relief?  All of us have unplugged something from an AC wall socket – a vacuum cleaner, lamp, extension cord or power saw.  There are really only two ways to do this, one, grab the plug and pull it out of the socket, or two, grab the wire or cable some distance away from the plug and yank.  Now we all now which is the proper way to unplug the cable; but we have used the wrong way too.  The latter method puts all the extraction force onto the contacts inside the plug.  If the wires weren’t connected to the plug strongly enough the cable wouldn’t last long.  This is an extreme example of why strain relieving is necessary, but it illustrates the fact that anytime a connector is on the end of a wire or cable there is the potential for force to be transferred from the wire or cable onto the connector.  Strain relieving is how engineers design cable assemblies, coiled cords and wire harnesses to withstand these forces.

Another purpose for stain reliefs is to help a cable assembly or coil cords withstand flexural forces.  This can be best illustrated using the metal coat hanger as an example.  Most of use have taken a metal coat hanger and wanted to make it shorter.  Usually we don’t grab a pair of scissors or wire cutters for this task.  Usually we find the spot on the coat hanger we want the “cut” to be and start bending the hanger back and forth, and eventually the coat hanger breaks.  This same effect can occur in wire and cable, and just like with the coat hanger once broken it cannot be used for its original purpose.  Here strain relieving is used by engineers to design a cable assembly or coiled cable to withstand bending the product might see during use.

To prevent failure from pull forces designers must “anchor” the wire or cable to the connector.  This is accomplished mechanically along with the electrical connection needed to transfer the signal or power the connector must carry.  This mechanical connection can be accomplished in many ways.  For many contacts a hole is placed in the metal through with the wire is passed and in essence tied onto the contact.  In other contacts the stranding is crimped by metal tight enough to become one with the wire.  These methods are only as strong as the wire itself and will only withstand a breaking force equal to the strength of the wire.

Cables and coil cords often have multiple conductors and the break strength of these is much stronger than that of any of the individual conductors within.  For these assemblies it is often desirable to anchor the whole cable and not just the individual conductors.  One way to accomplish this is to place something around the cable or wires that grabs onto the bundle.  This could be a metal band, a plastic tie wrap or even a knot.  Once the feature is on the cable it is placed against a feature on the connector, a metal housing, a plastic housing or over mold that transfer the force from wire of cable to the body of the connector.  This makes sure the force is not exerted onto the connector’s contacts which are often not able to withstand any great force.

To prevent failure from bending forces it is necessary to change how the cable or wire bends, not how much it bends.  Many coiled cords and cable assemblies are used in dynamic environments, and therefore must bend a lot.  The key here is to design a product that can withstand the bending.  Going back to our coat hanger example we know that the sharper the bend radius the quicker the coat hanger will break.  The same is true for any assembly made with wire or cable.  Here the designer’s goal is to increase the bend radius.  This can be done with an over molded strain relief that forces the cable or wire to bend in a large radius using a tapered shape with slots.  Another method is to design the product such that it contains a built in radius in the metal or plastic that allows the wire or cable to bend in a large radius.  Many times a simple section of heat shrink or a series of heat shrinks can accomplish the same result.

As is quite evident strain relieving is a critical component in most custom cables and wire harnesses.  In further articles we will discuss specific design situations, the solutions used and the testing results seen.  However sometimes it is necessary to rely on expert advice.  If you need help designing strain reliefs for your cable assembly or coiled cord Meridian Cable has over 30 years experience and often has existing solutions that can be used.

Anyone who has designed, purchased or used a CUSTOM COIL CORD has run into the problem from time to time.  There are two electronic assemblies and data or power needs to pass between them but nothing exists in stock that will work.  What to do?  The best solution is often a custom design.  But that is often costs too much, takes too long and is too difficult to design right?  It doesn’t have to be if the following pitfalls are avoided.

First, make sure the vendor can do the work.  I know this sounds simple but often it is overlooked for some reason.  Some great questions to ask are:

1. Does the vendor extrude wire and cable?
2. Is the vendor UL certified?  ISO certified?
3. Does the vendor add connectors, over mold, ultrasonic weld, attach electromechanical assemblies?
4. Can the vendor design the wire, cable, coil cord, connector, over mold, housings?
5. Is the vendor’s engineering “in house”?
6. Can the vendor perform advanced life testing?

Second, make sure the vendor can support your logistic needs.  Some questions to ask are:

1. Does the vendor accept blanket orders?
2. Can material be built ahead and warehoused?
3. Does the vendor have multiple inventory locations?
4. Is the vendor capable of shipping directly from the factory?

Third, make sure the vendor is cost sensitive.  Some questions to ask:

1. Does the vendor provide free engineering design?
2. Is warehousing a service or cost?
3. Does the vendor operate in a low cost manufacturing environment?  Offshore?
4. Does the vendor operate in multiple locations?  Countries?
5. Can the vendor provide a complete assembly, or just the cable?

In summary there are 3 key questions to ask.  Can the vendor do ALL the work needed to make a complete product?  Does the vendor have sufficient support services to take care of ALL the needs you have?  Is the vendor positioned to make sure ALL costs are maintained?  These are just a few questions that should be asked of any potential vendor you will hire to make CUSTOM COIL CORD.

Many people are gullible enough to believe that EVERYTHING imported is of poor quality.  This simple defies logic and anyone who makes a blanket statement as such surely doesn’t know the world we live in today.  Meridian Cable makes coil cords in China, designs them in America and is creating jobs in BOTH countries.  This cannot be said by some of our competitors.

First let’s address the quality issue.  If you have bought a cell phone, laptop computer, television or many other electronic devices odds are it was imported.  The same is true for many, many other items.  Kitchen appliances, furniture, medical devices, industrial controls and caskets are just a few of the items imported into America from overseas.  If the argument is true that everything imported is of poor quality how is it that there are excellently made examples of every item listed here?  The same is true of coil cords and cable assemblies.  The truth is you can find poor quality manufacturing ANYWHERE, and that includes America.  The important thing is to find a reputable company with a long history of quality performance.

Second let’s discuss why anyone would make such a blanket statement.  There are great manufacturing companies all over the world, and there are very poor manufacturing companies all over the world.  In this day and age surely everyone knows that excellent performance is not limited to any nation.  Anyone who thinks one country has all the advantages is limiting their option.  Granted there are reasons to buy from a given country and those do count.  However if quality is the only criteria then there are many countries that qualify.  The same is true of coil cords and cable assemblies.  The truth is you can find companies at each end of the quality spectrum in most countries.  A smart assessment would include ALL companies that can perform and not limit the options based on geography.

Third it is helpful to remember how small the world is today.  Sure the earth has not changed size in our lifetime, or for a few billion years for that matter, but from a business standpoint the world has never been smaller.  It took Christopher Columbus 5 weeks to cross the Atlantic in 1492, the first steamship took 18 days, Lindbergh 33.5 hours and today a modern jet makes the journey in 7 to 8 hours.  Technology has continuously made the world smaller with each passing generation.  Anyone who denies this fact is either purposely not telling the truth or is clinging to a lost world.

Last we all need to remember our business history.  There are countless examples of countries and companies who close themselves off to the options the world can afford.  China for example in 1100’s had paper, gunpowder and the compass CENTURIES before Europe.  And in the 1400s, 80 years before Columbus’ voyage they had 400 foot long, ocean going boats while Columbus’ boats were about 70 feet long.  China closed their borders, burned their boats, and was not a serious economic power for the next 500 years.

The point is obvious; any company that wants to grow and be competitive has to take advantage of every opportunity and resource available.  Anyone who says ALL the advantages are in ONE country is either not being honest, or is myopic and denying reality.  In today’s business environment, with the advancing in communication and logistics, any company can buy from any other company.  All it takes is find thing right partner.  When it comes to coil cords and cable assemblies Meridian Cable, being a global company, can be the best partner an OEM can find.  And we have added many jobs in AMERICA over the last few years, so if you are worried about American job creation Meridian Cable is doing that too!

Whether you call it a coil cord, coiled cable or retractile cord we have all seen the spiral cords used in many applications.  From garage doors, to cell phone car chargers, to medical equipment these cables are critical in achieving many design goals.  Whatever the design goal the primary reason for using this type of solution is to put a lot of cable or wire into confined space and have it available to extend when necessary.  Coil cords are a great way to accomplish this goal.

All coil cords have the same general shape, a straight section, followed by a coiled or curly section, followed by yet another straight section.  The extension capability of a coil cord comes from the coiled or curly section.  When the cable is pulled the coiled section acts like a spring and stretches.

For many applications the time required for a coiled cable to retract from its full working length is critical.  A number of factors influence the retraction speed of a coil cord but one important consideration is the raw cable’s geometry.  This geometry is typical round, but in special it can be rectangular or even ovate.  The advantages of each shape and the corresponding “bean effect” are explored below.

Every coil cord requires forces to extend it.  That force comes from the unwinding of the coils themselves but also from the bending of the raw cable along its length.  If viewed from the individual coil perspective what is happening can best be described as beam being bent.  In a round geometry the force required in any given direction is equal.  An easy way to visualize this is with a metal coat hanger.  If a straight section is held tight at one end and the other end pushed from the side, from the side, the force required to bend it in any direction would be very similar.  While other factors such as fabrication stresses, molecular orientation or grain do have an effect to some degree it is quite minimal in this application.  This design creates a coil cord with a typical retraction speed.

In order to achieve a faster retraction speed a coiled cable made from a rectangular shape cable can be used.  The rectangular shape adds force that can be best visualized using a ruler or a regular 2 X 4 board.  When these are laid flat with something supporting just the ends the middle is free to bend, and depending on the length it can bend quite easily.  However if the direction is changed and these are placed on edge they will not bend much at all.  When a coiled cord is made using a cable with a rectangular cross section this resistance to bending, or “beam effect”, augments the spring effect of the coils and creates a coil cord with a higher retraction speed.

Sometimes a round geometry is too slow and a rectangular geometry too fast.  In these instances a cable with an oval geometry can be used.  Since this cable is not round it has a higher beam effect, however since the cable is not fully rectangular the beam effect is less.  As one can imagine there are many variations between round and rectangular.  All the options lead to many design opportunities when designing a custom coil cord.

Should you need a standard coil cord or a custom design coiled cable Meridian Cable can help.  Meridian Cable has over 30 years of experience designing and manufacturing coil cords, coiled cables and cable assemblies. Designed – Built – Delivered, Meridian Cable is ready to help create a solution for you.

Many electronic devices, from toys to CD players, to computers, to jumbo jets need specialized cable assemblies to connect the various printed circuit boards, control panels and other electro-mechanical parts. Unlike cables for connecting a computer to its various peripherals, you can’t just go to your corner electronics store to pick them up. These are always customized assemblies, manufactured to meet the customer’s specific needs.

The term “cable assembly” can refer to anything from a two inch long wire with connectors at each end, to complex wiring harnesses that are hundreds of feet long, with many types of individual cables and termination points every few inches. The exact design of any cable assembly depends upon the product it will be used in.

The process of manufacturing these cable assemblies or wiring harnesses starts with the design of the product. Unlike other manufactured parts, the final drawings for cable assemblies aren’t produced before the prototype, but from the prototype. A schematic diagram is developed for the product, connectors are chosen, and the general routing of the cable is determined. Technicians build the prototype wiring harness in the prototype, which is then taken out for detailed drawings to be completed.

Cable assembly manufacturers work from these drawings and a wiring chart to build the necessary fixturing for the cable assemblies to be easily and accurately manufactured. Like any other part, accuracy is essential; however, unlike other parts, the flexibility of the wires in a cable assembly makes it difficult to maintain exacting tolerances.

In preparation for the actually assembly, the various wires, often of several different types, are individually cut and terminated with the right connectors or connector pins. In some cases, wire numbers, or other markings are placed upon the wires, to ease any necessary troubleshooting of the finished product. Automated tooling is used as much as possible for wire cutting, attaching terminals and connectors, and bundling the finished assembly.

In most cases, specialized cable assemblies are manufactured by hand. This means that the actual work of laying the individual wires in the proper place and inserting pins into the connector housings is done by an army of production workers. This is painstaking work, requiring a lot of attention to detail. One wire in the wrong place can render an expensive product inoperable.

Cable assemblies are held together in a variety of ways, depending upon the specific needs of the product manufacturer. Some are wrapped with electrical tape, others bound together with cable clamps and still others are tied together with a string that looks very much like waxed dental floss. In cases where the cable assembly is likely to encounter a lot of friction, a plastic “loom” is placed over the assembly to protect the cables.

Slow motion video has changed and the cable assemblies used to transmit the data have too. Meridian Cable was approached by a manufacturer of the camera used in this video: Video: Power Game .The customer contacted us about a custom coaxial cable assembly and we now supply them with coaxial cable assemblies that perform every bit as well as the players in the video. The video shows a great example of slow motion video in the age of high definition cameras.

All of us have seen a coaxial cable.  It has a center conductor, some insulation around the center conductor, then shielding over the insulation and finally an outer layer of material called the jacket.  If you have ever set up “cable” to your TV you have most likely handled and RG59 or an RG6 coaxial cable.  These cables are wonderful for basic cable, but won’t work at all for this video.

Meridian Cable’s customer needed FIVE coaxial cables inside a cable about the size of the RG59 or RG6 mentioned above.  These coaxial cables needed to be RG174 or RG316 equivalent and be completely insulated from the other coaxial cables in the bundle.  And to start they didn’t want to have to buy 25,000 feet. 

We were able to design this cable and run a sample quantity of only 1,000 feet.  This is truly what a custom cable assembly vendor like Meridian Cable should do.

As you watch the video remember that these are high performing athletes, and their power and grace makes what they do look easy.  Manufacturing a custom coaxial cable assembly is no different.  Meridian Cable makes designing and building custom cable assemblies look easy, and we do that every day for clients like you.

When you need a custom cable assembly or coil cord Meridian Cable can make your search easy.

Bud Kinzalow

Meridian Cable

We have all seen them, a coiled cable that makes connecting two electronic devices so much easier.  The benefits of a coiled cable are numerous, but the main purpose is so that a big pile of excess cable doesn’t lie around and get tangled.  A coiled cable can also be called a coil cord, coiled cord, curly cord, coiled wire or stretch cord to name just a few other names.  All these names are used in this article, but they all mean the same product. The question, how to make a coiled cable? Is answered below in four steps.

As with many things experience plays its part, so it is always best to consult with experts like Meridian Cable.

STEP ONE is to make a cable.  This can be as simple as one conductor or as complicated as a cable Meridian Cable recently made.  That coiled cable had 15 conductors; five twisted pairs, two 14 awg conductors, two 18 awg conductors and one 50 ohm coaxial cable.  Most coiled cables are not this complicated, but Meridian Cable can do it.

Since a coiled cable acts as a spring it is critical when making the cable that all the conductors are constructed right.  Things to consider are the size of the conductor stranding, the twist of the stranding, the direction in which the conductors are bundled and the insulation material used to name a few.

The final cable consideration is the outside jacket material.  This is critical because this is where most of the “coil” action in a coiled cable occurs.  Meridian Cable uses the following materials; polyurethane, thermoplastic rubber, thermoplastic elastomer and polyvinyl chloride.  Each material has applications it is suited for and these can range from medical uses to simple industrial control situations.

STEP TWO is to wind the cable onto a rod.  During this process the coiled cord starts to look like the final product.  The cable is wrapped around a rod the can be a small as 1/4 of an inch to a large as 3 or 4 inches in diameter.  The size of the rod creates the inside diameter (ID) of the coiled cable.  A small ID creates a coiled cord with more spring action and a larger ID creates less spring action.

STEP THREE is heat treating.  Since the outer jacket material is thermoplastic it can be softened with heat.  However too much heat will melt the material and too little won’t change anything.  The goal is to heat the material JUST hot enough and for JUST the right amount of time to get it to stay in the coiled shape.  This requires some experience and know how because if it isn’t done right then the coiled cord won’t perform correctly.

STEP FOUR is reverse winding.  During heat treating the material on the outside of the coil cord is lengthened and the material on the inside is shortened.  When the coil cord is reverse wound, or turned inside out, the force pulls the coils together giving the coil cord the spring action.

While these are the basic steps in making a coiled cable there are a lot of details that need to be considered.  A few things to consider are how many cycles will the coil cable experience, what kinds of environment will the coiled cable endure and what electrical properties are vital for proper performance.  Meridian Cable has the experience to talk you through the design considerations and show you how a quality coiled cable performs.  Call us and we will be happy to design your next coiled cable.

Bud Kinzalow ­ Meridian Cable