Interpower® North American and International Cable Manufacturing
Reels of copper conductor wire (cable) unspool one reel at a time with the aid of a Clipper lift allowing the spool to keep perfectly aligned with the extrusion line as it unreels wire. The wire is kept taut by using a tensioner on the front end and an accumulator on the back end. In the case of three-wire, all three conductors are extruded individually according to their color designation as ground, line, and neutral.
Watch how only one of two electrical cable and cord manufacturers in the U.S. makes cable and jacketed cords from reeled bare copper wire to finished reeled jacketed conductors wrapped and ready to ship.
Wire speeds down the line up to 1,000 feet per minute, the walls of the extruded conductors continually measured down to 1/10,000 of an inch. Multiple Laser-scanning devices measure the cable at strategically placed intervals along the extrusion line; a bank of LED readouts show real-time measurements and corrections in the width and thickness of the resin being applied to the conductors (both “hot” and “cold”) per specific cable standards. The laser-measured corrections take place before, during, and after liquified resin (hot) extrudes the wires and is measured multiple times down the line before entering the chilled water trough (cold) where yet another measurement is taken. Three separate extruders give the conductor wires their designated colors, such as blue, brown, and white.
Cold Water Bath on Extrusion Line
An extremely important process during cabling is the “length of lay” in which the rotating capstan entwines or braids the conductors to ensure the soon-to-be power cord will be flexible. This occurs right before the three conductors are respooled before heading down the extrusion line once again to receive their outer jacket.
North American and international cable are electrical conduits for power cords, cords that will include over-molded bridges to make country-specific plugs with proprietary diameters, pin and blade lengths. The plugs for specific countries are often shaped differently and will often have different electrical ratings. The cable itself has gone through several critical stations along the extrusion line: a wire-cleaning station, talc station (for easier stripping), multiple spark testers (to expose bare wire via nicks or cuts), a drying station, and a printing station to print marks on the cord such as a maker’s mark, agency approvals (UL/CSA/VDE), date of manufacture, type of jacket material (SJT/SJTOOW/etc.), and voltages and flammability ratings before the cable is spooled and wrapped for shipping.
Two Main Types of Power Cord Cables
The obvious difference in North American and international cable is how they are sized, one using AWG measurements and the other using mm2. While raw material differences are minor at best, it’s the standards from the agencies of countries that often differ slightly from each other—in Europe, cable must be RoHS and REACH compliant, which is not the case in most other countries. Another example is UL’s flame test versus IEC’s 60695-2 Glow Wire test, the former more concerned about preventing fire, the latter focusing on components overheating causing possible malfunctions. Typically, countries have their own approval agencies such as the United States (UL), Canada (CSA), and Germany (VDE).
Basic Cabling Material
Thermoplastic Thermoplastic can be softened through heating and hardened through cooling. It can be molded when heated and can retain its shape after cooling. Thermoplastic is the opposite of thermoset.
Thermoplastic Elastomer Thermoplastic or TPE is a material that has characteristics of rubber as well as thermoplastic.
Thermoset Thermoset uses a heating process—curing—and once the plastic is cured, it can't be altered from its original state.
PVC PVC is a common thermoplastic material for cable and conductor jackets and some molded plugs.
Rubber Rubber is also a common material for cable. It is a thermoset-type material. While it may be more costly than thermoplastic cable, rubber is extremely durable. Rubber is a good choice for outdoor applications.
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Interpower 100 Interpower Ave Oskaloosa IA 52577 United States
