( ( ( ( ( ( The ( rubber ( or ( plastic cover ) ) ) ) ( ( is usually ) ( in ( different colors ) ) ) ) , ) but ) ( inside ( , ( ( the wire ) ( itself ( is golden ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT The) (NN rubber) (CC or) (NN plastic) (NN cover)) (VP (VBZ is) (ADVP (RB usually)) (PP (IN in) (NP (JJ different) (NNS colors))))) (, ,) (CC but) (S (ADVP (RB inside)) (, ,) (NP (DT the) (NN wire)) (ADVP (PRP itself)) (VP (VBZ is) (ADJP (JJ golden)))) (. .)))
The rubber or plastic cover is usually in different colors, but inside, the wire itself is golden.
(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.