( This ( ( is ( why ( ( ( the ( electrical cords ) ) ( that ( ( connect ( your ( TV ( and ( other appliances ) ) ) ) ) ( to ( ( the ( electrical receptacles ) ) ( in ( the wall ) ) ) ) ) ) ) ( ( are generally ) ( made ( of ( ( copper wire ) ( covered ( with ( ( rubber or ) plastic ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (SBAR (WHADVP (WRB why)) (S (NP (NP (DT the) (JJ electrical) (NNS cords)) (SBAR (WHNP (WDT that)) (S (VP (VBP connect) (NP (PRP$ your) (NN TV) (CC and) (JJ other) (NNS appliances)) (PP (TO to) (NP (NP (DT the) (JJ electrical) (NNS receptacles)) (PP (IN in) (NP (DT the) (NN wall))))))))) (VP (VBP are) (ADVP (RB generally)) (VP (VBN made) (PP (IN of) (NP (NP (NN copper) (NN wire)) (VP (VBN covered) (PP (IN with) (NP (NN rubber) (CC or) (NN plastic))))))))))) (. .)))
This is why the electrical cords that connect your TV and other appliances to the electrical receptacles in the wall are generally made of copper wire covered with rubber or plastic.
(ROOT (S (NP (JJ Electrical) (NNS wires)) (VP (VBP are) (ADVP (RB usually)) (VP (VBN covered) (PP (IN with) (NP (NN plastic) (CC or) (NN rubber))) (S (VP (TO to) (VP (VB insulate) (NP (DT the) (JJ electrical) (NN wire))))))) (. .)))
Electrical wires are usually covered with plastic or rubber to insulate the electrical wire.