Power cord 15amp and 20amp

Hi Jim,

You are quite right regarding the UL certification. And I was referring to the fact that not all vendors are entirely candid in their descriptions (which is why I said, " just so you won't be confused/misled")

And while we're on the subject of UL certification, I recently found out that UL specifies that if a PC has a shield, that to be UL certified, the shield must be connected to ground at both ends -- which in all OEM cords they are (so the manufacturer of the amp, or whatever can get a UL rating on the equipment itself.)

Since (IMO anyway,) floating shields are preferable, I suddenly realized why a lot of aftermarket cords might sound a little better even though they're not that different in materials or construction than the OEM cord they replaced (and also why they're not UL rated, I guess.)

Neil, if the PC also has an equipment grounding conductor does UL still require the shield to be grounded on both ends? It would fly in the face of the way a shield works would it not. I was always taught to ground the shield at one end only and that being the end closest to the direction of earth ground, in this case the NEMA male plug.

If on the other hand a manufacture did not also include a separate equipment grounding conductor in the cord and only relied on the shield for the equipment grounding conductor then I could see where the manufacture would have to connect the shield also at the IEC connector end of the PC.

The manufacture of equipment can control whether they want to use the equipment grounding conductor of a power cord.
My Arcam Alpha 9 CDP has an IEC male connector and the connector does not have the equipment ground blade. The CDP does have a metal case, a Farady cage. They must build it insulated such that there is no chance of the case coming into contact with any power conductors.

Jim, yes, and yes. I totally agree with you about the desireability of floating the shield at the component end. A friend of mine, very knowledgable (formerly of Wadia) instructed me on interrupting the shield at the IEC end of an OEM PC to make it a floating shield. Away went all the digital RFI being broadcast from my DAC!

I agree with what you said in your second paragraph, but I've not seen any cords made that way (yet!)

Your last comment, I'm not sure about. It used to be true, but today, if you have 3-conductor hardware on each end of your PC, I think UL insists on a ground connection on each end (I'm not 100% sure on this one.)