Electrical cable

lastmod 2024-09-25created 2022-12-268 edits

A cable (Cable; North Korean standard: kkabel) generally refers to two or more wires or optical fibers bundled inside a protective sheath or jacket. Each wire or fiber inside the sheath is covered or insulated. Some cables contain both wires and fibers. Wires are usually made of copper because of its excellent conductivity, but aluminum is sometimes used to reduce cost.

Wires also need low electrical resistance and tensile strength. For this reason, 'stranded copper wire (銅撚線)', made by twisting several to several dozen copper wires about 5mm thick together, or steel-cored (鋼心) aluminum wire, with twisted steel wire in the core and aluminum wire around it, are often used. For 275,000V extra-high-voltage transmission lines, a bundled conductor method (複導體方式) is used, in which several such conductors are bundled together again. This is because a single line can carry only a small amount of power, and corona discharge forms from the wire surface into the air, increasing transmission losses, while the noise from that discharge is picked up by radios near the transmission line; the bundling prevents this.

Categories

• RJ-45
• Registered jack (RJ45, etc ...)
• Modular connector
• Twisted pair
  • Unshielded twisted pair (UTP; cable)
• Mini SAS / Mini SAS HD (SFF-8643) - When building a computer, there was an SFF-8643 <-> SATA x 4 cable from the motherboard.
• Small Form-factor Pluggable (SFP)
• Management interface (Console port; MGMT) - An administrator connects directly to the equipment to configure and operate it
• Serial port

Inside a wire

Wire and cable are terms for the many kinds of lines used to carry power or electrical signals,

and they usually consist of sheath -> insulator -> conductor.

Can't a wire be made as thick or as wide as you want?

The answer is no, it cannot be adjusted as you like. The reason is that wire thickness must be selected according to allowable current, voltage drop, and mechanical strength.

Allowable current

The maximum current that can flow through the wire for a given wire thickness

Voltage drop

The resistance caused by the wire when current flows

Mechanical strength

How sturdy the wire is

If a wire is made too thin, it can burn out when a huge amount of electricity or power flows through it. The sheath then burns along with it, which can eventually spread into an 'electrical fire'.

Because wire thickness is specified by standard in this way, the wire thickness of all electronics, power strips, and so on is manufactured to match the power and released on the market.

That is why the wire thickness of electronics and power strips on the market cannot be set arbitrarily, and you cannot choose a thinner wire, or one thicker than necessary.

Proper wire conversion table

So what are the criteria for selecting wire thickness?

Wire thickness is determined according to the proper wire conversion table in the Electricity Supply Terms and Conditions provided by Korea Electric Power Corporation (KEPCO).

It is summarized in the table below so it is easy to read. With the table, you can see why the wires of your home appliances were as thick, or as thin, as they were.

• Single-phase is the electrical standard used in ordinary homes
• Three-phase is the industrial electrical standard used mainly in factories
• SQ indicates the cross-sectional area of a wire; think of it as the cross-sectional area of the copper, called the conductor, inside the outer covering. The allowable current differs by SQ rating, and you should choose a wire with a rating that leaves margin over the power you use.

See also

• Adapter
• Electrical engineering
• Telecommunications (Korean: 전기 통신)

Favorite site

• Electrical cable - Wikipedia
• The importance of 'wire (cable)' thickness we overlooked! : Powerzone - Korea's No. 1 power strip manufacturing and distribution company