Are manufacturer AC cables good enough?

FWIW, the Marantz CD6006 CD Player is a good example of double-insulated equipment. As shown (link below), the IEC socket does NOT have a ground pin and the double-insulated logo (square within a square) is displayed in the Marantz box near the middle of the pic.
  
https://www.us.marantz.com/en-US/shop/hificomponents/cd6006#gallery-3

nsgarch:No, disconnecting the ground conductor at the EQUIPMENT end, as I specified, does NOT create a safety hazard.  However, disconnecting the ground conductor at the wall outlet end does indeed create a safety hazard!  A bit of research into equipment grounding techniques will explain why"

You are confused, uninformed, and ignorant regarding the nature of electricity, electrical circuits and grounding the defeat of any safety ground most positively, absolutely, and definitely without exception creates a possible, potential, "looming" safety hazard the result, consequence, and outcome of which can be deadly. I suggest you consult your Boy Scout handbook and look up definitions for "open circuit" and "closed circuit" and then report back.

You all must be talking about window unit air conditioning cables. 
I have central air and it's on a dedicated line directly from the breaker box.
Perhaps if you guys ran your window units off a dedicated circuit it might alleviate any quality issues you may be having. Just a thought...

This is not what double insulated means. Double insulated means that no single failure point can result in dangerous voltages (with or without equipment grounding). That could be two layers of insulation or reinforced insulation.


The ground connection can also be a critical part of an EMI reduction strategy.

"Double-insulated" simply means anything the user would be likely to touch is made of non-conductive material. In 120V code-compliant electrical systems, the neutral conductor is also connected to ground, and thus, to the circuit breaker.

When a builder stakes his reputation on his design, he will use a good cable.  When a product is subcontracted out, NO!  Jame Bongiorno, of GAS/Ampzilla fame,  was supposed to be a great designer, but compared to similar Julius Siksnius designed and built Audire equipment, it was junk.  The difference:  James had his stuff made by bidders; Julius built his own factory..