SoundMods wrote:Pelliott321 wrote:In the first photo you can see the house mains side with ground going over to the chassis ground, as well as each load side sockets grounds going over to the chassis ground.
Is this wrong
OK. I see that the transformer-casing ground bond is passed through to the IEC outlet. That brings me back to the question as to how your house is wired. My experiences with vintage residential electrical upgrades was that old-style fuse panels were replaced with circuit-breaker panel-boards and some easily accessible wiring upgraded to 2-conductor ROMEX with a 3rd ground bond wire. However, for the most part the bulk of the "buried" vintage wiring was left untouched even though modern receptacles were installed that have that third pin, the ground bond. In that case the 3rd pin is not wired to anything - or - maybe tied to the BX armor which is a major NO-NO.
This isn't correct. The cable we call BX, is actually type AC cable. It is similar to type MC cable. BUT MC has a green grounding conductor within the shield. The outer shield is to be grounded, but it is not UL listed AS a grounding/bonding means. Type AC cable does NOT have a grounding conductor within the sheath, BUT the sheath IS UL listed as a grounding/bonding means. It is perfectly acceptable to use type AC sheath (BX) as a ground. It is required to be connected to receptacle grounds. It's usually clamped to a metal box, then a ground screw is installed in the box and a jumper installed from the box to the receptacle.
BX is an excellent form of wiring! The conductors within are shielded from outside noise pickup as well.
It is not used as much any more because of material cost and greater labor to install. Type MC is usually used now in commercial applications and in high rise buildings. While the green ground is an improvement, unfortunately, instead of steel, the outer sheath is aluminum. [MC-Lite]. That sheath is subject to physical damage and a real PITA to install without breaking the shield. Still, a great wiring method.
For the ultimate audio or other noise-free application, I'd choose health care facility cable. HCF. This is a special MC cable with a SECOND ground inside. Use one ground for protecting the cable and enclosures from short circuits, and the second ground conductor to go straight to the (isolated ground) receptacle's ground terminals. That way, your equipment has the cleanest ground possible, and that ground is shielded from noise pickup along its length by the MC shield. If they make it in standard MC (not lite) it would only be bested, if at all, by metallic tubing and individual conductors within. Keep this in mind if you are going to install, or pay to have installed a dedicated circuit for your gear.
Stuart