5 Reasons Why Your Business Needs MI cable？

Below id from the Pyrotenax website. Why for single conductor but not for multi? Thanks


A brass plate is not required for multiconductor cables. Connect the brass termination gland directly to the steel enclosure using lock nuts on either side of the gland connector as shown in Figure 14. Ensure that the brass gland is properly bonded to the steel enclosure once the lock nuts have been tightened. Install multiconductor cables following all It is assumed that with a multi-conductor cable that all of the phase conductors and the grounded conductor( if there is one) are all in the cable and there will be no inductive heating where the cable passes through a ferrous enclosure. If you have single conductor cables, there will be inductive heating if the cables pass though a ferrous enclosure. You would remove the ferrous material, install the brass plate and pass all of the single conductor cables through the brass plate to prevent the inductive heating.

The MI cable that I've installed was #2/0 solid copper. If that were in a multiconductor cable you wouldn't be able to install it.

Brass plate photo from Google:

Egads! I don't want to think what all that cable cost per foot.

The MI cable that I've installed was #2/0 solid copper. If that were in a multiconductor cable you wouldn't be able to install it.

...

The multiconductor MI cable that I've seen had only a single copper jacket around two conductors embedded in one mineral-based insulating fill. Had to ray-chem insulate the conductors after stripping off the mineral insulation, inside the panel enclosure.

The multiconductor MI cable that I've seen had only a single copper jacket around two conductors embedded in one mineral-based insulating fill. Had to ray-chem insulate the conductors after stripping off the mineral insulation, inside the panel enclosure.

I think his point was 2/0 multi-conductor would be too hard to bend.


I have installed 10/4 MI cable and that was a chore to do.

The MI cable that I've installed was #2/0 solid copper. If that were in a multiconductor cable you wouldn't be able to install it.

Brass plate photo from Google:

A photo I took about 10 years ago.

I will post the rest.

What is the benefit to MI cable rather than say emt or another wiring method?

What very little that I know is its durability. It is like a fire pump, for mission critical applications it is supposed to survive a fire and still deliver power to its destination.

What is the benefit to MI cable rather than say emt or another wiring method?

Its very fire resistant.

I believe it is listed for 2 hours in a flame without shorting or failing.

The inorganic construction of mineral insulated cable makes it extremely fire and heat resistant. With an operating limit equal to the melting point of copper, ?F, ?C - it can easily withstand high temperatures and heavy current overloads. It emits no smoke or toxic substances and allows no flame propagation. In contrast, a third party test proved standard conduit and wire failed at 425?F. These fireproof properties make it the best choice for connecting motor operated valves, control stations, plant shutdown systems, instruments and power devices that must remain operational under actual fire conditions.

http://www.micable.com/mic05.html

What very little that I know is its durability. It is like a fire pump, for mission critical applications it is supposed to survive a fire and still deliver power to its destination.

In some of the posted pictures you can see the label stating "two hour fire resistant".
I guess that even if the copper tube softens the mineral insulation will still protect the wires to some extent.

Tapatalk!

Augie, That is an interesting read. How flexible is the MI cable ? Comparable to 1/2" soft copper water pipe ? Do you use any special benders or is it just armstrong adjusted to fit ?

For flexibility, I think it's more like ACR, the stuff you use for refrigerator water lines.

Commercial buildings have different electrical wiring requirements compared to residential structures. There are also different types of electrical wiring, each designed for specific applications. For example, wiring for electronics differs from what is required for heavy-duty machinery. Even the size of the building can affect the type of wiring used.

While safety is always a priority concern, there are other considerations to take into account when you are selecting commercial wiring projects. Here’s a look at the three primary types of commercial electrical wiring.

Please visit our website for more information on this topic.

Electrical Raceways

The NFPA 70: National Electric Code (Chapter 3) lists the requirements for commercial wiring. The chapter is aptly titled General Requirements for Wiring Methods and Materials. Chapter 3 also includes any exceptions pertaining to modifications.

Some of the requirements include securing and supporting the electrical installation, along with protection standards.

Electrical raceways and conductors are the most common types of commercial electrical wiring. Either a nonmetallic or metallic conduit is used with a multiple insulated phase. Some NEC requirements may also call for an equipment ground conductor. The installation requirements are based on the property’s design and specifications.

Some common types of conductors include THHN/THWN (thermoplastic high heat-resistant nylon jacket/thermoplastic heat and water-resistant nylon jacket) or XHHW (XLPE high heat-resistant and water-resistant) Most are comprised of copper, but you can also find aluminum conductors.

Electrical raceways are often used in commercial applications. Some of the types of raceways include,

• RMC (rigid metal conduit) is also known as RGS or GRC, a galvanized steel conduit with a thick wall and zinc exterior coating that’s used in applications where maximum protection against physical damage is required;
• IMC (intermediate metal conduit) is a thin-wall version of the RMC that features a corrosion resistant coating on the interior and a galvanized exterior;
• FMC (flexible metal conduit) is available in multiple types of metal and wall thickness.
• EMT (electrical metallic tubing) is the most common raceway in commercial construction, a threadless steel tubing with thin walls that has galvanized exterior and corrosion resistant interior.
• PVC (rigid polyvinyl chloride conduit) are available in several types, but mostly used as either Schedule 40 or 80, which refers to the thickness of the wall, for underground applications directly buried or concrete encased.

Don’t confuse raceways with cable trays. Cable trays are part of the structural system that supports and manages the various cables.

Even though electrical raceways are commonly used in commercial applications, they also have advantages and disadvantages.

Advantages

Link to Tongda

• It allows some changes in circuit configuration
• IMC, RMC & EMT can be used in places subject to physical damage
• Work well in electrical remodeling applications
• Raceways can be abandoned where the conductors are removed from the installation
• PVC underground installations are inexpensive

Disadvantages

• High installation costs
• It allows for a limited number of bends before requiring a junction box
• Installation can be more difficult compared to cabling systems because of more rigid routing requirements
• PVC has limited applications
• Some types cannot be installed in locations subject to physical damage

Electrical Cable Assemblies

Electrical cable assemblies use insulated and neutral conductors with a grounding one. The grounding conductor can be insulated or bare. If bare, the conductor is either wrapped in a metallic or nonmetallic covering.

The cable assemblies can be ordered as standard products or created for a specific conductor configuration. Standard cable assemblies typically come with THHN/THWN or XHHW-2 (copper or aluminum) conductors.

The most common types used in commercial buildings are:

• Armored cable (type AC) – feature a metallic sheath of either steel or aluminum armor, the sheath is also used as a ground path. It’s typically used for branch circuit connections between luminaires and power receptacles.
• Metal-clad cable (type MC) –are conductors within a metallic sheath of either steel or aluminum interlocking armor, but the sheath is not used as a ground path in this case. For direct burial or wet location, MC is available with an outer PVC jacket.
• Mineral-insulated, metal-sheathed cable (type MI) –are copper conductors within a seamless copper sheath with a magnesium oxide insulation. It’s used for specialized applications such as compliance with NEC 700 emergency systems.
• Nonmetallic sheathed cable (types NM, NMC, NMS) – also known as Romex, are conductors assembled within a nonmetallic, PVC-insulated sheath with a nylon jacket. It generally has a bare copper grounding conductor.
• Service-entrance cable (types SE, USE) – are conductors with an outer PVC jacket, assembled within a nonmetallic sheath with cable reinforcement. It can be used for service drops to a meter pedestal, but also as a distribution feeder to a branch circuit panelboard.
• Underground feeder and branch-circuit cable (type UF) –are conductors generally used for outdoor direct burial feeders, as well as branch circuits to detached garages. They feature a nonmetallic sheath with PVC insulation and a nylon jacket contained within a gray PVC outer jacket.

Electrical cable assemblies have advantages, but the commercial wiring also has a few disadvantages.

Advantages

• Lower installation costs
• Faster installation time
• No limit on the number of bends
• Factor tested before mounting
• Type MI is fire resistant

Disadvantages

• Need to be supported and secured at shorter spacing
• Cannot make changes after installation
• Are not suited for areas where the assembly may be damaged
• Requires more planning before installation

The Right Commercial Wiring Can Make a Difference

Using the right commercial wiring can make a difference in your commercial building. It also helps ensure your building meets current electrical wiring standards. Whether it’s electrical wiring for a new construction or you are upgrading your current wiring, contact one of our specialists to find out how we can help ensure your electrical project goes smoothly from planning to installation.

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