Wrapping power cords and interconnects with copper foil.

To clarify, with shielded power cables there are up to 3 ground conductors. A foil, a small drain wire, and a equipment grounding conductor which is the same gauge as the hot or neutral.

If the shield is braided there is no separate drain wire.

In case of a foil shield the foil is nestled against the drain wire. The drain wire is there specifically to make contact with the ground pin on the plug. You don’t actually connect a foil, when present, directly to that pin. It is this drain wire which you only connect at the wall side, and leave the equipment side unconnected.

The EGC, which is insulated and green gets connected at BOTH ENDS.

In the event of an equipment short from hot to chasis, the EGC alone carries that current.

@mitch2 said:

Are you assuming the shield is acting as the ground?

Not assuming, Stating a fact... IF it is connected at both ends with the EGC, (Equipment Grounding Conductor). (Therein male plug end and IEC connector end.)  It becomes a parallel EGC.

If a closed ground fault circuit is provided current will travel in the EGC as well as the parallel connected shield. Current does not discriminate. It will take any path that is provided back to the source. In this case the Utility Power transformer.

If you DIY your own shielded power cords only connect the shield to the EGC at the male plug end. Leave the other end of the shield, at the IEC connector, floating.

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@jea48 

”If you DIY your own shielded power cords only connect the shield to the EGC at the male plug end. Leave the other end of the shield, at the IEC connector, floating.”

That is actually how I have always done it. I have never constructed a cable, including interconnects, where the shield acted as the ground, although I have seen it done with some manufactured interconnects when configured as balanced cables.  My practice has been to always use a separate ground wire (same size as the connector wires) attached at both ends but to attach the shield only at the source end.  That has worked well for me.

@mitch2 

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A good example where a shield is also used as a signal ground is a Coax Cable.

Aluminum foil is hard to terminate, copper is easy. Also, not all shields are created equal - it depends on the mass density, and more is better. Canare Starquad is excellent, Mogami is good too, and easier to terminate. I only use the best Canare I can buy, with RCA’s terminated at the preamp. Do it once, do it right, and forget it.