En-Gauge

This month’s (or two month’s) edition of Wiring Harness News had a good article written by Anixter on “Thermoplastic vs Thermoset Wire and Cable Materials.”  Since we highlighted this subject last month, we thought we’d give you some more information.

Firstly, Anixter created a nice reference graph listing general characteristics of the two material types and their implications to users:

“The variety of materials available to modern wire and cable manufacturers is immense.  This results in a wide range of properties within each material type.  The table is a generalized summary that does not apply to every material.  It is important to understand how the properties impact the performance of the product in the intended application.  Generally speaking, within a given material type, the old adage, “You get what you paid for,” still applies.”

Aside from describing the main characteristics of the two materials, which we did in our original post, they offer some thoughts in response to the question of how do I choose a material for my application?

“Knowing that the key difference between a thermoplastic and thermoset is in the way they respond to elevated temperatures can be an important aspect of which material to choose.  For example, thermoset materials are often chosen for circuits that may experience and overload.  This is because thermoset materials have a reduced likelihood of failure if momentarily operated at the higher temperatures that often accompany an overloaded conductor.  Comparatively, thermoplastics are often easier to strip, which makes them easier to process on automated equipment for large volume applications.”

Some great additions, thanks to Anixter.  You can find their full article here (.pdf format)

If you work anything like we do around here, you’ve probably gotten into the habit of using all the wire acronyms in the book, but may not have spent a ton of time reflecting on what they mean in a while.

Well, we opened up our old manuals again to refresh our memories, and thought we’d remind everyone else while we were at it.

Wire Insulation Abbreviations

Let’s test it out:

RHW: Rubber insulated, moisture resistant, good up to 75°C

USE-2: Underground Service Entrance wire that can stand wet environments up to 90°C

XHHW: Cross-linked polyethylene insulation, moisture resistant and good up to 90°C in dry environments

Photo credit: Tom Magliery

The insulating materials commonly used to cover copper wire (and other) electrical conductors fall into two broad classes: Thermoplastic and Thermoset.

What’s the difference?

If we take a look at our Fundamentals of Rome Wire and Cable Manual (yes, it’s from a long time ago but yes, it’s still entirely applicable), we have the following descriptions:

Thermoplastic: This material is one that will soften and even melt when exposed to a sufficiently high temperature.  In other words, when the material is originally compounded, it becomes relatively hard yet pliable, much like most plastics we encounter in our daily lives.  However, if it is exposed to high temperature at some future time, it softens and melts. The major reason for selecting a thermoplastic material is because it is the most economical type of insulation.

Some of the commonly used thermoplastic insulations used nowadays:

PVC (Polyvinyl Chloride)

PE (Polyethylene)

ECTFE

PVDF

Nylon

Thermoset: This material, on the other hand, does not soften when exposed to high temperatures.  Once it’s compounded and cured, it becomes “rubbery” and retains its properties even when exposed to high temperatures….Thermoset insulations are usually used where the wire or cable will be exposed to high temperatures.

Some thermoset insulations often used are:

• XLPE
• CPE
• EPR

[UPDATE: We've added a few more pieces of useful information on this topic here]

Photo credit: John

There are many tests used to measure the flame resistance of various copper wire and cable products. Flame Resistance is usually defined as the ability to stop burning once the source of heat is removed.

The following tests are most commonly used in North America.

Vertical Tray Flame Test

UL 1581/IEE 383
This test is performed on cables attached to a 1′ wide, 8′ tall vertical metal ladder tray.  A 10″ ribbon burner with an air/propane mixture applies 70,000 BTUs/hour of combustion for 20 minutes, 24″ from the bottom of the cable.  The cable must self-extinguish before the flame reached the top of the tray.

CSA FT-4
This test is a later version of UL 1581 and is more strict.  To pass, the resulting char can’t be greater than about 4.5″ (1.5m).

IEEE 1202
The newest version of UL 1581, this is essentially identical to CSA FT-4.

UL 1685
This is more or less UL 1581 with an added smoke emission requirement.  If it passes, a wire can be given a “Limited Smoke” listing.

ICEA T-29-520
Yet another version of UL1581, the only difference is that the BTU value is 210,000 instead of 70,000 and the cable spacing increases.

Vertical-Wire Flame Test

UL 1581 VW-1
This was the first flame test developed for studying how flames spread on wire and cable.  The test is performed with a 24′ wire and a Tirrill burner.  Two clamps hold the single sample vertically.  The burner is mounted at a 20° angle and applied for 15 seconds, then reapplied four more times each time the wire stops burning.  If the sample doesn’t burn more than 60 seconds after any of these burning sessions, or if less than 25% of the indicator flag burns, or the cotton batting is ignited during the test, the wire passes.  A “tray rated” cable must pass this test as well.

CSA FT-1
The Canadian version of the VW-1 test.

Are you looking for information on Kris Tech’s status as an American manufacturer? If so, you can visit our website.

Passed last February, the American Recovery and Reinvestment Act of 2009 was full of provisions to preserve and create jobs, invest in infrastructure, as well as energy efficiency and science, offer assistance to the unemployed, and stabilize the State and local economies.

Suppliers, manufacturers, distributors and contractors all have to consider what this means if they’re working on any ARRA-funded project.  As a copper wire manufacturer, we certainly have to think about this, and have gotten plenty of questions from our customers about “Made in America.”

There’s a lot of information out there on the subject, and sometimes it can be difficult to sort through.

The portion of the ARRA that we’re interested in is the Buy American Provision Section 1605.   To start off, it is a combination of two already-existing pieces of legislation: the Buy America Act of 1933 and the Buy American law of 1964.

Buy American Act of 1933

• Applies only to “US government procurements and construction projects” – or when the federal government directly buys products or itself builds public buildings or works that are followed-through on behalf of a public authority, as covered by the Federal Acquisition Regulation (FAR).
• Requires that any manufactured good used in these projects must be assembled in the US with US and foreign material and have more than 51% of their content produced in the US.

Buy America law of 1964

• Applies mostly to Federal Transit Authority (FTA) grants given to states and localities.
• Address the use of manufactured goods and construction materials components (parts and supplies incorporated directly into the final manufactured product or construction material).
• Requires that 100% of the components mest be made in the US for it to qualify. This is much more stringent than the Buy America Act.

Section 1605 of the ARRA – the Buy American Provision – brings aspects of both of these past laws together. It states the no funds given under this Act can be used for a public building or public works project (anything federally funded, as well as all state or locally-funded projects) unless “all iron, steel, and manufactured goods used…are produced in the US.” FAR Subpart 25.6, which implements Section 1605 above, says that “there is no requirement with regard to the origin of components or subcomponents in other manufactured construction material, as long as the manufacture of the construction material occurs in the United States.”

What does all this mean?  Where are the lines drawn?

Foley & Lardner Law Firm gives a good rundown of certain parts we’re concerned about:

“Subpart 25.6 curiously avoids defining precisely what is required for manufactured construction material to be considered “produced” or “manufactured” in the United States. But given Subpart 25.6′s definition of “manufacturing,” by implication construction material will be considered “produced/manufactured” in the United States when it results from processing into a specific form and shape or combining of raw material into a property different from the individual raw materials, and that processing/combining occurs in the United States…..Even more important, Subpart 25.6 specifically provides that there is no component or subcomponent origin requirement for domestic “manufacturing” status. Thus, for purposes of the ARRA, construction material will acquire domestic origin status when manufactured in the United States without regard to the origin of its components.”

Keep in mind, there are stricter guidelines for some projects under the FTA and FHA, as they’ve decided to comply with the existing Buy America law for all ARRA grants, which makes it easier for them to qualify projects. Therefore, they go by the “100% domestic” requirements.

What all of this means to us is that we’ll need to work closely with our suppliers and our customers to make sure the requirements are met appropriately on any ARRA-funded project.

The government keeps information on the ARRA up-to-date if you’re interested.  Or you can read the entire text of the Act

Are you looking for our Tracer Wire?

Tracer wire, which is also called locating wire or locator wire,  is used to assist in locating pipes and other lines after they’ve been buried in the ground.

Once a pipe is laid down, tracer wire is placed along it’s length and buried next to the pipe.  This wire is what’s actually searched for if the pipe itself needs to be located (hence the name).  A Wire Tracer – an above-ground device with the ability to locate non-energized wire – is used so there’s no need to send electricity through a tracer wire in order for it to be detected.

After the wire is found, crews can start a much more accurate dig to reach the pipeline for maintenance, repairs or replacement, and site destruction is greatly reduced.

Used most commonly in the utilities industries (water, gas, sewer, fiber optics, etc), tracer wire can also be used in directional drilling applications, as well as irrigation systems and golf course sprinkler systems (Little Known Fact: Kris Tech Wire got it’s start by selling tracer wire to the golf course developers!).

You may be interested in more information on how tracer wire is installed or what types of tracer wire are the best to use in certain situations.

We’ve just gotten back from the NACE Corrosion Show down in San Antonio TX.  While we didn’t exhibit, it was great to see some customers and learn what’s happening in the industry.

You can check out more about our Cathodic Protection products if you’re interested.

Kris-Tech Wire at NACE 2010