To Float or not to Float...

Correction:

If a piece of audio equipment is Class ll rated the power cord will be two wire. In the US and Canada at least the NEMA 5-15P or 5-20P plug will be polarized so it can only plug into the wall receptacle in one direction.

That should read NEMA 1-15P plug. A 125V 15 amp two wire polarized plug.
Example:http://rockyroadweb.company/ebay/2_prong_stereo_cord1.jpg

They make a NEMA 1-20P plug, but I have never seen one.....

Jim

First the IC cable is not approved to be used as an equipment grounding conductor by any recognized third party testing laboratory. NONE.

This is exactly how more than half the source equipment that use earth figure eight two pin mains cable get their earth reference, via the interconnect.
We in Australia have one of the most stringent mains safety rules and regulations as we are 240v (lethal), nearly our sources have their mains reference given by the interconnect, and guess what we don't have many earth hum noise problems, because we don't get many ground loop issues.
We may get a earth loop problem when two mono blocks poweramps amps each have earths and are plugged into different power points who's earths take different routes around the house, this can sometimes create a loop, usually then one is floated (not ideal I admit) or we get longer leads and plug then both into the same power point.  

Cheers George   

This is exactly how more than half the source equipment that use earth figure eight two pin mains cable get their earth reference, via the interconnect.

IF the equipment is Class ll (Double Insulated) Listed that uses a two wire power cord and plug, why do you think it still needs to be earth grounded?

Jim

You clearly don’t know or understand.
It still has to get a total system reference earth via the interconnect shield, if you disconnected that shield at either end (and be left with a single wire connection) you get a massive noise.

Cheers George

georgehifi
2,766 posts                                                                   09-14-2017 7:50pm

You clearly don’t know or understand.
It still has to get a total system reference earth via the interconnect shield, if you disconnected that shield at either end (and be left with a single wire connection) you get a massive noise.

Cheers George

George,

The safety equipment grounding conductor is for electrical safety. It is not needed for the normal operation of home audio equipment. IF the audio equipment is not Class ll power rated, and Listed, for use of a two wire cord and plug then a three wire cord and plug shall be used and the equipment grounding conductor shall be bonded, connected, directly to the metal chassis of the equipment... The equipment grounding conductor is there to carry any leakage and or ground fault current back the electrical service service entrance neutral conductor where all branch circuit equipment grounding conductors connect. (Note the electrical service entrance neutral conductor is bonded to the service equipment cabinet enclosure as well is connected to the earth.)

2014 NEC

Grounding Conductor, Equipment (EGC). The conductive path(s) that provide a ground-fault current path and connects normally non-current-carrying metal parts of equipment together and to the system grounded conductor or to the grounding electrode conductor, or both.

~ ~ ~

Georgehifi
It still has to get a total system reference earth via the interconnect shield,

No it does not need an earth reference.

I don’t think you understand the difference between an equipment grounding conductor and a signal ground conductor.

Yes the signal ground wire of an interconnect cable must be connected to the signal ground of the source and the signal ground of the receiving load.

As for a shield. Not all ICs are shielded. And when a shielded IC has a separate signal ground wire, the shield as a rule is connected at one end only. Granted the shield of a coax cable must be connected at both ends. It is the return signal ground conductor.


Full circle.....

georgehifi
2,766 posts                                                              09-13-2017 5:08am

This is extremely dangerous - interconnects are not intended to carry safety grounds.

No it’s not as many sources have two pin mains plugs and rely on the ground from the next stage via the interconnect same goes for some preamps.

If you were to have a grounded mains plug at the source and the poweramp you have created an earth loop with the ground wire between the power points as the interconnect carry the earth as well.

Cheers George

Jim
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