In summary, inspectors should understand the different types of conductors that are commonly found in homes. Disregarding any inherent inadequacies, existing KT cable systems are likely to be unsafe because they are almost guaranteed to be at least 50 years old. Some insurance companies refuse to write fire insurance for houses with this type of wiring, although this may be remedied if an electrician can verify that the system is safe. Knob-and-tube wiring is more vulnerable to damage than modern wiring because it is insulated with fiber materials and varnish, which can become brittle. Support devices that may damage the cables, such as bent nails and overdriven staples, are not permitted. They must be protected, secured and clamped to device boxes, junction boxes and fixtures.

Northern Cables Inc. manufactures CSA approved aluminum AC90. Cables are manufactured with two, three, or four 8000 series aluminum ACM conductors insulated with RW90 cross-linked polyethylene rated at 600 volts from #8 AWG to 250 MCM. These cables are made identically to the copper based ones. AC90 is a flexible interlocked aluminum armoured cable approved for use in open and concealed wiring in dry locations. If it is MC, it may have a bonding strip (Southwire’s AP), and there are three sheath types allowed, besides the various coverings we now see.

The red hot coil of stretched out flex burned half of the old building down. Type MC is permitted for services, feeders and branch circuits, indoors or outdoors, exposed or concealed.

One really has to stop and be intentionally specific to make sure one is discussing the correct wiring method so as to cite the proper provision of code. Just another of the many reasons why it is so important to consider the precision of code language when describing a condition, method, citation, etc. I ran into an entire system in a high-rise condo today. At first glance into the panel I was perplexed at the lack of ground wires.

What Is Romex? What Is 12

Older BX cables without an internal bonding strip arenot accepted by NEC. Today, residential construction primarily uses three types of wiring, Non-Metalliccable being the most common; followed by BX , and individual conductors run inside conduit. In Part One I discussed knob and tube wiring and the potential problems and issues that may arise if your home still contains legacy knob and tube. Perhaps your home normal balance still contains knob and tube, or you are considering remodeling or planning new construction. In this article, I will explain current options and residential wiring best practices. Type AC cable is approved by the NEC for use only in dry locations. In order to comply with the NEC for use in wet locations, interlocked Type MC Cable must have a corrosion resistant jacket and wet location rated conductors.

They are not permitted inside homes, with the exception of “style R” SE cable that can serve as interior wiring in branch circuits for ovens and clothes dryers. Style R cables should be clearly marked on their jacket surfaces. Commonly known as SWA cable, the steel wire armoured cable is a power and auxiliary control retained earnings cable, designed for use in mains supply electricity. Used for underground systems, cable networks, power networks, outdoor and indoor applications, and cable ducting. NM cable is permitted to be run exposed on thesurface of the building finish. If subject to physical damage thenit requires supplemental protection.

National Armored Cable Manufacturers Association

MC can have a smooth or corrugated metallic sheath or, most commonly, interlocking metal tape armor. The sheath may be steel or aluminum, which is non-magnetic and therefore suitable when used with a single conductor, so as to avoid an induced voltage on the sheath. MC is also availible as HFC cable which has a bonding strip as well as a full sized ground. This cable can be used in a patient care area or for an isloated ground circuit. Individual conductors run inside conduit is used primarily in industrial and commercial applications, and is rarely used in residential wiring.

I was wondering when/if conduit is required instead of BX. For me, its just way faster easier to run BX, but I’ll do conduit if I have to. AC90 is a cost effective alternative to conduit wiring. Online Accounting AC90 eliminates the need for conduit, fittings and the labour associated with pulling in wire, threading, and forming conduit. Multiconductor and special construction AC90 can be manufactured.

What Is Metallic Sheathed Cable?

Larger circuit breakers can be custom ordered with a means to apply a lock installed on the circuit breaker itself. If you lay the BX out straight, strip out one end, clamp the wires in a vise, then pull the outer jacket off. This same problem is a real issue where people have attempted to use the armor as a ground because if the insulation fails on the hot wire you may in fact have a potential on the armor.

If you have to tear out a wall to replace a wire that has been punctured by a nail, supposing you were hanging a picture, this repair could cost well over $1,000. Many of my concerned clients have spent a lot of effort and money to shield against and reduce their exposure to electric fields. Some even go as far to turn off the circuits to their bedrooms when they sleep to reduce their exposure.

• HBOGo has become such a massive success for cable network HBO that they will start to offer the service as a stand-alone option.
• Armored cable and Metal Clad cable have a flexible metal armor of similar outward appearance, but that is where the similarity ends.
• But what that protection is will depend on where the wires are installed and the environment of the installation.
• A review of FCC installation requirements provides some insight on the reason for such prohibition.

There is armored cable and there is flexible metallic conduit. In some instances the flexible metallic conduit can be exposed to weather but it requires special insulation on the conductors. BX is also known as Armor Clad or Flexible Metal Conduit cable.

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It consists of individual, insulated conductors pulled from a spool through a conduit, either metal or PVC. This is a more difficult and time-consuming wiring method but is more efficient in commercial applications where wiring runs must be exposed and thus must be inside some form of conduit. The wire is protected by 2 layers of insulation, with each individual conductor being insulated and the entire bundle also being insulated.

Bx Cable History

However as mentioned previously armored cable first discussed 1903 not 1905. Here is something I stated “my 1905 NEC does reference AC “, you then stated “I don’t believe the term type AC showed up until the 30s.” Although 1959 is important regarding the bonding wire no distinction btwn MC or AC prior, 1990s changes are more important regarding EGC. The earlier bonding “wire” was a flat ribbon subject to breakage – cannot be relied upon for safety or as EGC. AX like another form of flexible armor-tubes used for other uses, but when used for electric wiring in structures had a problem.

The Rome came from the town in New York and plant name where the wire was manufactured originally. Keep in mind that the AC cable is required to have a anti short bushing also. Member NEC panel decided that the contact of the 2 bolts that attach the receptacle yoke to the box does not create a “robust” ground.

Outlet was grounded when attached to the box but became ungrounded when not on contact . An MC cutter is needed to cut the sheath with no danger of nicking the conductor insulation. As to bx cable definition why the engineer specified something, you’d have to ask him. I am not aware of any location where pipe cannot be used as a general wiring method in place of any of the “flexible” methods.

Inside NM cable, the hot and neutral conductors are side by side, thus NM emits a much smaller, more localized and weaker magnetic field. The magnetic field strength drops very quickly with distance from the NM cable.

The various types of metal-covered cable are made in a similar fashion. These copper wires are covered in their own plastic insulation, keeping them separated from the metal cover and each other. Next comes the metal covering, which protects the wire bundle from physical impacts and wear. The metal is generally a long metal strip that winds around the cable; this gives the metal covering a corrugated, spring-like appearance.