Twisted Pairs (Trips)

A question was posed to me today about Boeing's depiction of shielded twisted pairs and twisted triples on their wiring prints.

The wires can be shown with an oval or a figure 8 representing the shield.



Of all the aircraft types referenced (737, 757, and 767), the oval shielding is always grounded and the figure 8 shield is always open.

Either way..... these wires should "all" be twisted. I have never seen two (three) conductor wires inside a shield that are not twisted. The drawings can possibly make you think that the oval shield wires aren't.

Standard colors are red and blue for twisted pairs. Red, blue, and yellow for twisted triples. Wiring prints sometimes show a R,B, or Y behind the wire number.