​​Why White Powder used inside Electrical Cables?

According to capacity, applications of the electrical cables different types of powder are used such as talcum powder, magnesium oxide(MgO) Powder, Swellable powder, Chalk Powder, etc.

●Talcum Powder in Electrical Cables:
Talcum Powder is used in some low current-carrying cables such as computer power cable to make it flexible, to stop the internal wires from getting stuck to the outer rubber casing. When a cable is used over a long period of time, its outer rubber gets sticky and can be broken down. So to prevent this problem talcum powder is used in some electrical cables.
●Magnesium Oxide Powder in Electrical Cables:
Magnesium oxide powder is used in high current carrying cables, Mineral Insulated(MI) cables. Magnesium oxide powder has two very useful properties that are high thermal conductivity, low electrical conductivity. Magnesium oxide powder gives a lot of features and advantages in an electrical cable which are given below,
When a high current flowing through a cable, heat produced which can damage the cable. Due to the high thermal conductivity property, Magnesium oxide powder can conduct the heat from inside of the cable to outside and prevent the damaging of the cable from the heat.
Due to low electrical conductivity property, magnesium oxide powder provides good electrical insulation.
Magnesium oxide powder provides good lubrication to electrical cables.
Magnesium oxide powder makes electrical cables fireproof.
Magnesium oxide powder makes electrical cables flexible.
●Swellable Powder in Electrical Cables:
Swellable Powder is used in electrical cables to block the water and to eliminate the moisture issue. These powders can form a gel-like material when contacting with water and block the flow of water. These powder swell and expands to block the water permanently.
●Chalk Powder in Electrical Cables:
Chalk Powder used in some cables to provide fire resistance. To prevent wires inside a cable from fire, chalk powder is used in some electrical cables.