To twist, or not to twist?

[BobTurner]

Originally Posted by Steve Crewdog

K
If twisting 2 wires going to the same destination is good, why not do that for all (i.e., wires going to various switches) before lacing them into one big bundle? Is it because of the bulk that would result from lacing a bunch of twisted 2 wires runs together?
TIA

As you noted, twisting wires results in ‘shortening’ the pair, so you need more wire. More weight, more money. So it’s generally only done for circuits which are sensitive to noise pick-up. Audio mike circuits, yes. Landing light circuits, no. Unless your landing lights use a pulsed LED driver that can radiate noise. Then no becomes yes.

[Steve Crewdog]

Originally Posted by BobTurner

As you noted, twisting wires results in ‘shortening’ the pair, so you need more wire. More weight, more money. So it’s generally only done for circuits which are sensitive to noise pick-up. Audio mike circuits, yes. Landing light circuits, no. Unless your landing lights use a pulsed LED driver that can radiate noise. Then no becomes yes.

Thanks Bob, makes sense. It's surprising how fast a little extra wire here and there adds up to a lot of weight.

[YellerDaisy]

Originally Posted by Steve Crewdog

It's surprising how fast a little extra wire here and there adds up to a lot of weight.

Not sure if it is acceptable to quote Burt Rutan here but.... for those that haven't heard it... The test to know if a part is too heavy for an aircraft is to toss it into the air. If it comes down, it's too heavy.