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Topic: Twisted pair wire lead (Read 714 times) previous topic - next topic

Twisted pair wire lead

My hwh control unit calls for a twisted pair power. It's DC and I did not think there was much noise in DC wiring. Near as I can tell I can get about 8" of twisted pair to the bullet connectors as they exit the harness. Due to a dead short somewhere I will be bringing a new fused hot from the ignition solenoid up to the bullet terminals. Do I really need a twisted pair all the way back to the dash?
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Twisted pair wire lead

Reply #1 –
Quote from: Old phart phred –
My hwh control unit calls for a twisted pair power. It's DC and I did not think there was much noise in DC wiring.

We've seen a lot of noise on 12V, especially on the return side of things (what some folks call "ground").  Current flows in a loop from source to load and back to source and will take the path of least impedence.  Sometimes that means it flows in unanticipated conductors to get back to its source... (especially when those designing the electrical wiring treat "ground" as a giant hole in the ground where all current flows, rather than as the set of return paths it really is)

You can also get noise coupling via crosstalk if a 12V hot/return is routed close to another source of current. 
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320
 

Re: Twisted pair wire lead

Reply #2 –
when my headlights go on I get feedback into the speakers with radio off, (same thing?), I have to turn the radio on or turn the dash lights all the way down to squelch it. I usually turn the radio on and turn it down.. Same noise?