Running power and signal cables- A Different Question

I've heard that if you run a power cable accross a signal cable at a 90 degree angle, so the two cables form a '+', interferance isn't possible.

How true is this?

[eviljohn2]

It depends what sort of interference you're talking about but there is certainly some truth in the statement.

[Reiner]

Originally Posted by aramil2003

I've heard that if you run a power cable accross a signal cable at a 90 degree angle, so the two cables form a '+', interferance isn't possible.

How true is this?

I would put it like this: two cables running in parallel ('=') are more likely to interfere with each other than cables running at an angle (with 90 degree being the max/best).
As so often there might also be cases in practice where you won't have any problems running cables in parallel, say if the signal cable has a very good shielding.

So should I run them like this or route a new track around the signal cable (instead of accross).

[demostenes]

Hi all,

There's always interference even if u run a power cable near a low voltage cable (even from telecom transmitters like cell phones and radio signals) therefore most people try to place them as far from each other as possible. Of course when crossing its wise to cross them at 90º. Why?... ..

The electromagnetic waves travel in a helicoidal way on AIR, try to imagine an airplane propeller. The cable is for guidance only. As most power cables are unshielded (for electrical waves) and with poor insulation there's always a leakage which results is spray magnetic and electrical fields which in turn injected parasitical voltages or currents in the nearby cables.

What can we do:

1- Increase the distance
2- Use + for crossings
3- If u have to run both cables parallel , use successive twisted loops so that the magnetic (only) induced voltage is reduced

Sorry the short lesson .

Beekeeper as a looong explanation in: Video Cables [MEGA LONG] All you need to know?