( ( Installation ( of ( ( ( ( ( ( ( ductwork , ) piping ) , ) ( electrical wiring ) ) , ) and ) insulation ) ) ) ( ( is underway ) . ) )
(ROOT (S (NP (NP (NN Installation)) (PP (IN of) (NP (NP (NN ductwork)) (, ,) (NP (NN piping)) (, ,) (NP (JJ electrical) (NN wiring)) (, ,) (CC and) (NP (NN insulation))))) (VP (VBZ is) (ADJP (JJ underway))) (. .)))
Installation of ductwork, piping, electrical wiring, and insulation is underway.
(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.