Passing Wires Through Panels

[Wayniac]

I've read on this forum multiple times, that passing a single conductor through a metal panel is not recommended.

It has been posted, that a twisted pair passing through a metal panel is the preferred practice.

I'm curious, can someone please explain this to me? Thanks!

 

[2 picoDumbs]

Probably depends more on what the function of the single wire is.
Wires are passing through holes all the time. Think about the rear panel of the amp

 

[Zen Mod]

we just like to have some fetishes

 

[rayma]

a twisted pair passing through a metal panel is the preferred practice.

Currents flow in loops, so there has to be some route back to the source of the current.
If the way back isn't near the wire, then there's a large loop area that can result in noise problems.

 

[Wayniac]

Probably depends more on what the function of the single wire is.
Wires are passing through holes all the time. Think about the rear panel of the amp

Specifically, I'm building an F5 using diyAudio V3 PCBs. The wires I wish to pass through are the DC power and return. The wires will terminate on the F5 PCB about 1 cm after passing through the panel.

I plan on minimizing exposed wiring by running the both the AC and DC wiring in separate channels milled into the under side of the amplifier.

Attached is an image of my planned component lay out.

An externally hosted image should be here but it was not working when we last tested it.

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[2 picoDumbs]

You don't need to run single wires through holes to achieve what you want here.

Even though that transformer looks nicely shielded, I think I would place the transformer right next to the front panel of the amp with caps in the middle of the amp case.

 

[Wayniac]

You don't need to run single wires through holes to achieve what you want here.

Even though that transformer looks nicely shielded, I think I would place the transformer right next to the front panel of the amp with caps in the middle of the amp case.

Are you suggesting I twist the three DC power leads for transition through the panel?

Regarding the transformer location, I'll take that under consideration.

Thanks for your help. This is my first build...


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[2 picoDumbs]

Do you mean 2xDC and 0V twisted together?

 

[Wayniac]

Currents flow in loops, so there has to be some route back to the source of the current.
If the way back isn't near the wire, then there's a large loop area that can result in noise problems.

Thanks for this explanation. Many of the F5 photos I see here have individual wires for the DC runs to the PCBs. Of course, they are direct runs not passing through any chassis panels.


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[Wayniac]

Do you mean 2xDC and 0V twisted together?

Yes.


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[rayma]

Thanks for this explanation. Many of the F5 photos I see here have individual wires
for the DC runs to the PCBs. Of course, they are direct runs not passing through any chassis panels.

Those wires should be twisted. It really doesn't matter if they go through a panel or not.

 

[AndrewT]

Any circuit connection requires a wire for the current to flow from the source and a wire to allow the current to return to the same source.
Break either of those wires and the circuit will not work.
EVERY inter module connection MUST use a wire pair. There are no exceptions.
Even the dual polarity twisted triplet from PSU to amplifier is two pairs with one half of both pairs commoned.

Now that you have pairs of Flow and Return wires, you decide how to arrange them.
Big loop areas equals big interference.
Small loop areas equal low interference.

For least interference use a twisted pair, or a coaxial.