The cable size should be indicated on the sheath. In a 1.5mm cable, the cross-sectional area of the earth wire is 1mm. The measurement of a 2.5mm cable is 1.5mm. The electrical cable size chart amps with reference to plasterboard ceilings or joists covered by less than 100 mm thermal insulation is presented below. The actual load capacity of the cable depends on the type of metal it is made of and its thickness. The thicker the metal wire, the more current it can carry.
The voltage rating of a cable is the maximum operating voltage that it will tolerate without damage. A cable with an excessive voltage rating for its size may produce heat and smoke, and could start a fire if exposed to electricity. The larger the gauge number, the higher the voltage rating. For example, a 2 awg cable can handle 120 volts, while a 4 awg cable can withstand 450 volts. Cables are selected so that they can handle at least 75% of the expected maximum load current. Cables with smaller sizes of wire inside require greater lengths to reach the same current capacity as those with larger sizes of wire.
The ampacity rating of a cable is the maximum continuous current it will safely carry. The term "continuous" means that the cable is capable of carrying a large current for a long period of time without damage. An ampacity rating is expressed as the maximum current in amperes (amps) that the cable can safely carry over its length without burning itself out.
Cable Sizes Chart
|Auto Size||Nom Area mm2||Amp Rating|
In addition, cables for sockets on a ring or radial main are typically 2.5 mm in diameter. The cross-sectional area of the individual wires within the cable—the actual size of the exposed face of the wire—is measured here. If no such designation is present, then it is assumed to be a #24 cable (0.5 mm thick aluminum sheath with 24 2.5 mm internal wires).
Cables used as feeders into a distribution center or large office building can be 2.5 mm in diameter, but more commonly they are 5 mm or 3/4 inch (19 mm or 22 mm) instead. Cables used as subpanels out in the field will also usually be 2.5 mm rather than 4 x 4 x 0.5 inches (10 x 10 x 1.25 cm).
The term "two and two-half millimeter" may also apply to telephone cables. These are mostly four conductor cables with an insulated inner core and a semiconducting cover material around it. The two conductors that carry the signal and the two conductors that carry ground are each equal in length to each other and both pairs are wrapped in parallel layers with adhesive tape or another binding material. A pair of conductors is also called a strand.
A typical telephone cable is about five feet long.
Around 25 millimetres Modern cables are generally 25 millimetres (0.98 in) in diameter and weigh roughly 1.4 tonnes per kilometer (2.5 short tons per mile; 2.2 long tons per mile) for deep-sea parts, which make up the majority of the run, with larger and heavier cables used for shallow-water sections close shore. The oldest cable on record is the Venerable radio cable that was laid in 1923 and still operates today.
The largest cable in world history was the Transpacific Cable, which consisted of eight segments each about 1650 miles (2600 km) long and weighed about 21,000 pounds (95,000 kg). It was installed between 1969 and 1977 to connect America with Asia via Oceania. It has been reported that it is still operating after almost 30 years!
Another huge transoceanic cable system is the European Undersea Networking Programme (ENIP), which was launched in 1995 by 14 European countries with the help of the United States and Japan. Its goal is to provide high-speed Internet service to all Europeans by 2013. So far, it consists of three main lines that pass through the Middle East and Africa, connecting Europe with North America and Australia.
In addition to these large-scale projects, there are also many smaller-capacity cables that are used for local area networks within a single country or region.
We are all aware that when a wire is used to feed the full load of a house, it might be sized smaller than when it is not used to feed the complete habitation. For example, if I were constructing a 100 amp service, I would use # 2 aluminum SE wire, despite the fact that # 2 aluminum is generally rated at 90 amps. The reason for this is that when I'm wiring a home for the first time, I like to oversize my wires in case I need to replace or move something later on.
The actual size of the wire depends on how much current it has to carry and its designation. The two main factors are the material it is made of and the specification listed on the box or cable. For example, # 2 aluminum SE wire is almost always about 1/2 inch in diameter, while # 4 copper THHN wire can range from 0.038 to 0.065 inches depending on the manufacturer. A wire's capacity is indicated by its gauge. For example, 20-gauge wire can carry 20 times more current than 16-gauge wire of the same size.
As far as length goes, the wire needs to reach from one circuit breaker to the next until it reaches another switch or transformer. In other words, a wire must connect each breaker with every other breaker or outlet.