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Electrical FAQs

Is installing ARMOR-X® different than for interlocked armor cables?

Yes. The core for ARMOR-X® must be stripped using a cutting tool while interlocked armor cable can be peeled back to proper length. ARMOR-X is more difficult to train in close quarters than interlocked cable; however, both constructions can be difficult unless the contractor has the proper equipment.

Are the ampacity ratings different for ARMOR-X® than for interlocked armor products?

No. Contact Wire and Cable Technology Support for more details.

Can the cable be installed in an aerial application?

Yes. If supported properly by a correctly sized messenger.

How many conductors can be installed in the continuous welded armor?

On sizes 600V AWG #14-10 we can include up to 37 conductors. On sizes 600V AWG #8 stranded through 500 kcmil, we can install 4 conductors with 2 ground wires or 3 conductors with 3 ground wires. Check your catalog sheets for more specific details.

Can aluminum insulated conductors be installed in the continuous welded armor?

Yes. We can put any of our insulated conductors in the ARMOR-X® core.

How does the price of ARMOR-X® compare to interlocked armor?

The price is 5% to 20% higher for ARMOR-X® depending on quantities and sizes.

How often does the ARMOR-X® need to be supported when installing?

The cables must be secured to supports every 6 feet.

What are other features of ARMOR-X® in addition to the impervious armor?

This cable construction is a complete wiring system that’s ready for installation with phase-identified conductors. The product meets and exceeds industry standards. Medium voltage constructions include proven EPR compounds for insulation, providing excellent corona-free cable. The 600v XLPE insulations are tough, reliable and proven compounds that have been used for many years by Southwire Company, LLC.

Where is the product primarily used?

Petroleum and chemical companies use the majority of the product. Pulp and Paper ranks second in usage. A relatively new application involves the use of high speed variable frequency AC drives (VFD) connecting to the motor. (A flyer & IEEE paper written by Dave Cooper and Dave Mercier is available from Southwire Records Management.) However, the product can be installed in any location that Type MC cables are allowed per the NEC. If the end user is concerned about reliability of the electrical conductors, we have an opportunity to up-sell from interlocked armor to ARMOR-X. The basic selling feature is the excellent protection provided by the impervious cable construction.

Which of our competitors offer the continuous welded armor product?

Okonite (CLX) makes a complete size and voltage range. Rockbestos (Gardex) makes a complete size range but stops at 5kV non-shielded. Nexan (Corflex) manufactures a partial range but offer a complete range. They outsource their sizes of medium voltage. General (Philsheath) manufactures a partial range but also offers a complete range. They outsource their 600v sizes. Nexan’s manufactures their product in Canada. Rockbestos is in Connecticut, Okonite makes the product in Kentucky and California and General in Indiana.

Where can ARMOR-X® be installed according to the NEC?

Reference the catalog sheet for a listing of the areas.

What type of armor is used in ARMOR-X cable?

All Southwire ARMOR-X cables include a copper-free aluminum armor that holds up to fatigue failure in all types of installations.

Are the fittings and connectors available for ARMOR-X®?

Yes. The Armor-X mini brochure has a complete list of connector manufacturers and connector sizes.

What size range can Southwire manufacture?

Currently, Southwire manufactures:
600V AWG #14 to 750 kcmil multi-conductor cable power (w/grd) and control (wo/grd)
5-15kV MV up to size 3/c 750 kcmil MV-105
Please check catalog sheets for dimensions. For voltages higher than 15kV, please contact power cable department.

Does ARMOR-X® have a ground wire in the cable core?

Yes. This is added to provide additional safety and to meet or exceed our competitor’s products.

What is an HL (Hazardous Location) environment?

It is the most explosive environment with a designation of Class I, Division I. The cable designation is MC-HL. All conductor required in this environment must have a separate equipment ground. The armor cannot be used for grounding.

Can the continuous welded sheath be considered as a ground conductor?

Yes. The circular mil area of the aluminum sheath is adequate to serve as a ground wire, according to NEC Table 250-95, but only in Non-HL locations (Class 1, Div. 1)

Will the cable pass the ICEA T-29-520 210,000 flame test?

Yes. However, the cable cannot be marked as such.

Can the ARMOR-X® be directly buried in earth or concrete encased?

Yes.

Can the cable be installed without a jacket?

Yes. It can be installed without the jacket; however, the coefficient of friction may increase and the chances of damaging the armor are increased. We would not recommend installation without the jacket unless the application warrants this type of construction.

Does the cable have an outer jacket?

Yes. PVC is the most common. It can be manufactured in various colors. It can also be jacketed with oil-resistant, sunlight-resistant and flame-resistant compounds.

Why would an end user prefer this type of construction over interlocked armor?

This type of construction is completely impervious to moisture, gas, and fluids. It keeps out contaminants that could cause premature failure of the conductors if the contaminants were allowed to penetrate the armor. With interlocked armor cable, moisture and contaminant penetration is possible. Continuous armor provides greater reliability over the long term when compared to interlocked cables - assuming all other factors are equal.

 

Does the smooth core have to be corrugated?

No. It is not necessary, but normally is done so that termination fittings will securely fit over the armor and lock in place. Close fitting terminations are needed to make a good ground connection. Corrugation also makes the armor more flexible and less likely to crack during bending.

How is the armor made?

 

The armor is made by forming an aluminum strip around a cable core. Where the edges of the strip butt together, they are welded electrically to form a solid smooth core. The core is then pushed/pulled through a machine tool that causes indentations or corrugations. The addition of the corrugations gives the cable flexibility.

What is ARMOR-X?

ARMOR-X® is Southwire’s product name for a continuous welded aluminum armor that is corrugated. When jacketed, it has the appearance of an interlocked armor cable.

 

What about the use of a pin connector/adapter for aluminum?

The use of pin connectors, also referred to as pin adapters, is acceptable for use with aluminum conductors. A pin connector used with aluminum conductors may be used if the existing equipment terminations are rated for use with only copper conductors. Pin connectors may also be used when existing terminations are not sized correctly for the aluminum conductor. In this case, a pin connector can be used to transition from the aluminum conductor to the incompatible termination. Adapters are intended to be assembled using the tool specified by the manufacturer in the instructions which are provided by the pin connector manufacturer. Incorrectly installed connectors can lead to overheating and failed connections. The most common point of failure in electrical circuits is at the termination. Using pin connectors actually increases the number of connections and can increase the risk of failure. Pin connectors typically require proprietary tools and a specific number of crimps, resulting in the chance for installation errors to be greater than with set-screw connections. The specification and installation of pin connectors should be avoided unless conditions deem them to be necessary.

What about compressed connectors for aluminum?

UL Listed compression connectors are available for aluminum, copper, or dual-rated for both copper and aluminum. Compression connectors may be pre-filled with anti-oxidant. Based on field experience with installations, set-screw connections are equally reliable for use with copper and aluminum conductors. UL Listed mechanical set-screw lugs have proven to be highly reliable with AA-8000 or copper conductors. Set-screw lugs provided with equipment are made with a tin plated AA-6000 series aluminum alloy body. Connectors manufactured without this plating are rated for aluminum conductors only. Because standard lugs are dual-rated, they are plated with tin to avoid galvanic corrosion between the copper conductor and the aluminum connector. When terminating a conductor with a compression connector, the bare conductor should be inserted into the connector barrel and crimped with the tool and die recommended by the connector manufacturer. The compression connector is typically marked with the required die size. Excess oxide inhibitor should be removed after the crimping process is complete.

What about set-screw connectors for aluminum?

When terminating a conductor with a set-screw connector, the bare conductor should be wire brushed and an oxide inhibitor applied to the bare conductor. Unless included in the connector manufacturer’s instructions this is considered a best practice and is not a requirement. The screw should be tightened using a calibrated torque wrench to the appropriate torque value as recommended by the connector manufacturer. An over tightened screw’s performance can be as detrimental as an under-tightened screw. Over tightening can lead to damaged conductors and connection points. Proper tightening or torqueing is necessary to attain a reliable connection. Once the correct torque is achieved, there is no need to go back and re-torque the lug with an AA-8000 series aluminum alloy conductor.

How can I be sure I'm making a reliable termination?

A thin layer of oxide naturally occurs on aluminum and copper conductors and will be broken by the physical act of tightening the setscrew connection or crimping the compression connection. Wire brushing aluminum or copper conductors should be performed if the connector manufacturer recommends this in their installation instructions. If required, brush the exposed conductor before applying the oxide inhibitor and terminating the conductor. This will remove the oxide on the exposed conductor and remove any contaminants that may interfere with the connection. Oxide inhibitor use is considered good workmanship for all aluminum or copper terminations. The oxide inhibitor provides a barrier at the connection point that prevents moisture and other potentially damaging environmental substances. The oxide inhibitor must be listed for the application. Oxide inhibitors are made for use with copper, aluminum, or both copper and aluminum. Compression connectors typically come filled with an oxide inhibitor. When tested per UL 486B, mechanical set-screw terminations are tested without wire brushing and oxide inhibitor is not added if the connector is pre-filled with an oxide inhibitor.

What makes AA-8000 Series aluminum so reliable?

The alloying and annealing processes used with AA-8000 aluminum conductors results in an AA-8000 conductor that is more flexible than the equivalently sized copper conductor based on ampacity. It should be noted that NEC® Table 312.6(B), requires the same bending space at terminals for equal ampacity AA-8000 conductors. A 500 kcmil copper conductor requires the same bending space as 750 kcmil AA-8000 aluminum conductor. Pulling aluminum conductors requires less tension resulting in less damage during installation. It should be noted AA-8000 series aluminum alloy conductors have a higher strength to weight ratio than copper conductors resulting in a higher safety margin when pulling in aluminum conductors. Also, copper is about twice as heavy as aluminum to achieve the same conductivity. This results in AA-8000 aluminum having a clear advantage over copper when pulled through conduit, especially in vertical installation. When installing conductors in vertical conduit runs NEC® Table 300.19(A)provides the distances required between supports for the conductors. Pulling tension calculations should always be made before installation.

What practices would Southwire recommend when installing aluminum building wire?

Southwire has always recommended the same basic process for installing aluminum building wire as copper building wire. The conductor’s insulation should be stripped from individual conductors using tools manufactured for the conductor type and insulation type, or by standard methods such as penciling or whittling the insulation from the conductor. The installer should never “ring cut” the insulation due to the risk of nicking the conductors inside. One perception with aluminum building wire is that it is more susceptible to breaking than copper building wire if nicked during installation. This is based on the older AA-1350 aluminum wire used prior to 1972. The EC-1350 aluminum was 99.5% pure aluminum, hard-temper and was more sensitive than copper building wire to nicks during  installation. This is no longer true with AA-8000 aluminum alloy building wire. AA-8000 aluminum is a fully annealed aluminum alloy conductor that is very strong and flexible.

Where can I get information about installing aluminum conductors?

NECA/AA 104-2000 “Recommended Practice for Installing Aluminum Building Wire and Cable” defines a minimum baseline of quality and workmanship for installing electrical products and systems and was referenced in the 2008 NEC.® This standard was jointly developed by the Aluminum Association and NECA. It should be noted that NECA is also developing a standard for installing copper building wire.

When installing MC feeders what fitting must I use and are “red heads” required?

The NEC® requires that these MC fittings must be “Listed and Identified” for use with MC Cables, (NEC Section 330.40). No red heads are required on any type of MC Cable. However, please contact you Local Inspector to verify. The NEC does require that “red heads” be used on AC Cables. Reference NEC 320.40.

What connector do you recommend for use with MC Feeder cable?

Arlington MC Cable Fitting: 8412 – 8417

What is the maximum space between supports?

The NEC® requires that MC Cables be “supported” and “secured” every six feet. Reference NEC® Section 330.30(C).

How often does MC need to be supported?

Per NEC 330.30(C) Supporting – unless otherwise provided, cable shall be supported a interval not exceeding 1.8M (6FT)

Is MC Cable with “interlocked jacket rated for” Ducts or Plenums?

No – Neither “interlocked jacket armor” or “PVC Jacketed MC Cables” can be installed in a plenum. Interlocked Type MC Cable without an overall nonmetallic jacket can be installed in air-handling areas. Please reference NEC® 300.22(C).

Are there any limitations on the number of bends permitted in MC Cables?

No – The NEC has no restrictions on the number of bends for MC Feeders or Branch Circuits.

What is the cost savings when using MC Feeder?

On average, Cable Design Evaluator shows a 50% savings.

When terminating aluminum MC Feeder, what additional steps need to be taken?

None, same procedures as copper, per the NECA aluminum association guide.

How much side wall pressure can MC handle?

Per UL 1569 gauges 6&8 is 1000 lbs per inch and 4 and larger is 2000 lbs per inch.

When installing MC Feeder do I attach the pulling rope to the interlocked armor?

No, attached the pulling rope to the conductors in the cable. See podcast installing MEGA MC for further details.

What is bending radius of MC?

Per NEC 330.24(B) Interlocked – Type Armor or Corrugated Sheath. Seven times the external diameter of the metallic sheath.

What type of phasing is available?

MEGA MC™ is available in low voltage and high voltage colors.

Can MC be used in wet locations?

MC can be used in wet location per NEC 330.10(A) (11) which states – MC Cable can be used in wet locations when the insulated conductors under the metallic covering are listed for use in wet location

What coefficient of friction should I use when calculating pulling tensions for SIMpull THHN<sup>®</sup>?

When installing SIMpull THHN®, Southwire recommends the same COF used to evaluate standard lubricated THHN installations.


The specially designed pre-lubricated SIMpull THHN® product has a COF as low as 0.17 when following best installation practices. This has proved to be true through miles of cable pulling tests.

Recommended practice for calculation pulling tensions is to begin with a conservative coefficient of friction such as 0.35. This will provide some safety factor for any debris in the conduit or other unexpected field conditions. Southwire’s application engineers utilize a 0.35 COF when evaluating cable pulls. This conservative approach is a result of not having the ability to evaluate the condition of the conduit in the field.

How do I make sure that phase taping does not slip off THHN?

The tape should be applied in half–lapped layers with sufficient tension to produce a uniform wind (for most applications this tension will reduce the tape’s width to approximately 5/8 of its original width). Apply the tape with no tension on the last wrap to prevent flagging. Locate the phase tape near the end so it will be under the pull head and protected during the pull.

How do I keep a cable coil secured for transporting?

The key points in creating a secure coil are the type of tape used, taping the cable ends, and placing secure wraps on the cable after it is removed from the coiling head.

Using a vinyl electrical tape will provide some compression as the tape is stretched and will move and give as the coil moves. The most important point is back-wrapping the cable end with tape to provide and area for the tape wraps to stick to the ends and secure them. Finally, the coil will likely relax once it is removed from the coiling head. At this point tight and secure wraps should be applied around the coil at the loose cable ends and in at least a couple of evenly spaced areas around the coil. Taping in three to four locations on the coil will usually be secure.

The tape should be applied in half–lapped layers with sufficient tension to produce a uniform wind (for most applications this tension will reduce the tape’s width to approximately 5/8 of its original width). Apply the tape with no tension on the last wrap to prevent flagging. A two to three inch band of tape is adequate for most coils. This is best practice for all THHN.

What is the recommended method for tying THHN conductor ends to reels with rope?

Staples are typically used to secure the conductor to the reel. If using rope, use friction tape to secure the rope to conductor. Tying the conductor in two locations with rope may be sufficient to eliminate slipping.

How do I make sure that my counter wheels do not slip when rewinding THHN?

From our experience, Older and poorly maintained equipment may suffer from numerous issues. The counter wheels will become polished with use, and may result in accuracy issues. The wheels can stiffen on the shaft and not spin as freely as they should, and finally, the springs are subject to fatigue and need to be replaced regularly.

The machines also need to be cleaned and lubricated regularly to keep parts moving freely with as little friction as possible. Counter manufacturers recommend replacing the springs every 6 months to a year depending on the amount of use. The springs cost $37.80 for a set. Older machines should be re-furbished to alleviate the wear problems.

The following offers solutions that are common to conductors slipping in cable feeders.

Problem

Solution

Too little pinching force.

Engage ratchets another notch.

Too little tire pressure.

Inflate tires to 22 psi.

Upper drive unit unplugged.

Plug in upper drive unit.

Reel(s) hanging up or dragging.

Inspect cable reels for free unobstructed operation.

Will Southwire's new SIMpull THHN® reduce the occurrence of nylon splitting in the field?

Yes. Southwire's new SIMpull THHN® results in less stress on the nylon during installation resulting in less splitting. It should be noted that the major contributor to nylon splitting is installing THHN in cold weather.


If installing in cold weather, the cable should be stored in a heated environment overnight prior to installation. Cold temperatures approaching freezing can cause the insulation to become stiff and possibly brittle. Care should be taken to mitigate the effects of cold weather when installing in these situations. The cables should be kept in heated storage for at least 24 hours prior to installation and only removed from heated storage just prior to installation. Cables installed in cold weather should be handled more carefully and pulled more slowly. Even given these mitigating methods Southwire does not recommend installing thermoplastic insulated cables at temperatures below –10C (14F).

What causes nylon damage in underground conduit?

Nylon damage in underground conduit seems to occur more frequently than in conduit systems indoors. We have observed that nylon tearing rarely occurs in clean conduit. Underground conduit, despite efforts to keep debris out, will collect dirt, rocks, and other debris. It is recommended that all conduit is cleaned out prior to conductor installation, especially if it is underground conduit. Care should be taken to ensure the cable is centered in the conduit when paying off the reel. A conduit bushing should be used to reduce the possibility of the conduit lip damaging the cable.


Specifying Conduit Proofing Cable is commonly damaged due to debris left in the conduit during installation. Prior to pulling the conductors it is considered good practice to proof the conduit system. The purpose of proofing the conduit system is to ensure the conduit is intact, not crushed or disjointed, and the conduit is clear from debris that could damage the conductor jacket or insulation. This is accomplished with the use of wire brush mandrels, duct swabs and mandrels.

How do I eliminate the rope from breaking when pulling with forklift?

Pulling conductors with vehicles is never recommended. This method results in the tension surging and spiking during the pull. These spikes in tension can damage the conductors and exceed the rated tension of the rope or other pulling devices. It is nearly impossible to perform a smooth pull using a vehicle. That's why recommended practice is a tugger. It never hurts to check rope for wear. Ropes must also have tensile strength greater than the calculated pulling tension-- assumes pulling tension is calculated beforehand. Ropes also lose tensile capacity after significant use/abuse. Southwire has worn out more than one rope in our testing of the installation of conductors in conduit. When using a tugger with monitored tension, a rope should have tensile strength greater than maximum possible pulling tension of the tugger.