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PostPosted: May 3rd, 2020, 5:32 pm 
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Joined: January 15th, 2015, 7:19 am
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Location: Baltimore MD
Did not have time today to look at it
Maybe tomorrow.
I feel I have pretty good mains here now that rewired with a dedicated circuit and 10 gauge wire, all new sockets and breakers.
I always wanted to try an iso. But getting that open ground put a stop to it, for now


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PostPosted: May 4th, 2020, 7:45 am 
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Whose bright idea was it to tie an entire room into a bathroom GFI?


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PostPosted: May 4th, 2020, 9:30 am 
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Pelliott321 wrote:
here is the schematic of the tranny
Attachment:
The attachment isoxformer_web.jpg is no longer available


you can see that I wired brown and orange to neutral and red and yellow to hot
the filter is my version of a felix...... just x1 caps across mains and a common mode inductor in series then another set of x1 caps
this is another one but essentially the same
https://www.audionervosa.com/index.php?topic=6727.0

any help would be greatly appreciated


Sorry for all this. Over the weekend I was only looking on my phone, and not very carefully.

I see now that you have paralleled the output windings. No sweat, but now you must make a ground connection, since this is a separately derived system. The rule is, at the SOURCE of the separately derived system (that is, within the isolation transformer enclosure) you must bond together the grounded and grounding conductors: the white and the green. So, you've used the brown and orange leads as your neutral. 1) Mark them with white tape, to indicate a neutral. 2) Connect a green set of conductors to the brown/orange connection and connect them to the receptacle ground pins. Disconnect 3) Disconnect the building grounds from the receptacle ground pins (that being the green wire from the power cord. 4) Connect a green or bare wire from the green/brown/orange splice to the grounding electrode system in the house. You can make this connection using a ground clamp on the cold water pipe, close to the existing clamp; in the main circuit breaker panel, on the bonding jumper (neutral bar), or spliced with a split bolt connector (commonly called a "bug"), right onto the grounding electrode conductor (wires running from the circuit breaker panel to the grounding means (rods, cold water, etc.)

All of the above is a must and the only challenging part should be the long wire to "ground".

Side note: leave the ground wire from the power cord of the transformer enclosure connected to the chassis of the transformer.

ALL the above assumes that the receptacles you've installed in the transformer are ISOLATED GROUND. if NOT, they will short you're new separately derived ground and the new cold water ground creating a parallel grounding system almost guaranteed to introduce noise into the system.


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PostPosted: May 4th, 2020, 9:31 am 
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Pelliott321 wrote:
here is the schematic of the tranny
Attachment:
isoxformer_web.jpg


you can see that I wired brown and orange to neutral and red and yellow to hot
the filter is my version of a felix...... just x1 caps across mains and a common mode inductor in series then another set of x1 caps
this is another one but essentially the same
https://www.audionervosa.com/index.php?topic=6727.0

any help would be greatly appreciated


You need new receptacles, those are most definitely NOT IG, isolated ground.


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PostPosted: May 4th, 2020, 9:48 am 
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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


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PostPosted: May 4th, 2020, 9:50 am 
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Joined: December 14th, 2013, 2:19 pm
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mix4fix wrote:
Whose bright idea was it to tie an entire room into a bathroom GFI?


I couldn't find the post to which you are referring.

GFCI receptacles installed in bathrooms are to have no outlets outside of bathrooms connected to them.

Does this help?

Stuart


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PostPosted: May 4th, 2020, 10:01 am 
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Joined: July 24th, 2015, 4:17 pm
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Location: Parkville, Maryland
Stuart Polansky wrote:
Pelliott321 wrote:
here is the schematic of the tranny
Attachment:
isoxformer_web.jpg


you can see that I wired brown and orange to neutral and red and yellow to hot
the filter is my version of a felix...... just x1 caps across mains and a common mode inductor in series then another set of x1 caps
this is another one but essentially the same
https://www.audionervosa.com/index.php?topic=6727.0

any help would be greatly appreciated


Sorry for all this. Over the weekend I was only looking on my phone, and not very carefully.

I see now that you have paralleled the output windings. No sweat, but now you must make a ground connection, since this is a separately derived system. The rule is, at the SOURCE of the separately derived system (that is, within the isolation transformer enclosure) you must bond together the grounded and grounding conductors: the white and the green. So, you've used the brown and orange leads as your neutral. 1) Mark them with white tape, to indicate a neutral. 2) Connect a green set of conductors to the brown/orange connection and connect them to the receptacle ground pins. Disconnect 3) Disconnect the building grounds from the receptacle ground pins (that being the green wire from the power cord. 4) Connect a green or bare wire from the green/brown/orange splice to the grounding electrode system in the house. You can make this connection using a ground clamp on the cold water pipe, close to the existing clamp; in the main circuit breaker panel, on the bonding jumper (neutral bar), or spliced with a split bolt connector (commonly called a "bug"), right onto the grounding electrode conductor (wires running from the circuit breaker panel to the grounding means (rods, cold water, etc.)

All of the above is a must and the only challenging part should be the long wire to "ground".

Side note: leave the ground wire from the power cord of the transformer enclosure connected to the chassis of the transformer.

ALL the above assumes that the receptacles you've installed in the transformer are ISOLATED GROUND. if NOT, they will short you're new separately derived ground and the new cold water ground creating a parallel grounding system almost guaranteed to introduce noise into the system.


And now you know why electricians make the BIG $$$$. Stu nailed it! :thumbup:

_________________
Walt


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PostPosted: May 4th, 2020, 10:12 am 
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Joined: July 9th, 2016, 7:23 pm
Posts: 27
Location: Fairfax Station, VA
Stuart Polansky wrote:
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


What he said. The second ground is usually referred to as a "technical ground." Implied in Stuart's green description is that it be insulated so as not to conduct to any other grounds until it reaches the service entrance ground, or as close to it as possible. Also, if using noise filters, I would connect their ground(s) to the first ground, i.e., the "safety ground", at the chassis star ground, so as to not send diverted noise currents down the technical ground. This would cause noise voltages on the technical ground reference, the magnitude being dependent upon the noise current and the resistance of the technical ground conductor. In this case, it would be best to place the filters on the primary side, as close to the power cable entrance as possible. Also, put the star chassis ground as close to the entrance of the cable as well, to keep all loops as small as possible, and wire lengths as short as possible to minimize inductance.

If your transformer has a shield wire, I would connect it to the technical ground.


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PostPosted: May 4th, 2020, 10:19 am 
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Joined: January 15th, 2015, 7:19 am
Posts: 1104
Location: Baltimore MD
thanks guys this will take some time which I do not have right now but I still have a couple of questions
first
Isolated ground receptacle. Does this mean that the ground lug (usually painted green) is not connected to the neutral in the socket or is there more to it.
because I am pretty sure these are isolated ground sockets
I need to clarify the drawing so I understand it.
I will post it here and get comments


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PostPosted: May 4th, 2020, 10:28 am 
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Joined: July 9th, 2016, 7:23 pm
Posts: 27
Location: Fairfax Station, VA
Pelliott321 wrote:
Isolated ground receptacle. Does this mean that the ground lug (usually painted green) is not connected to the neutral in the socket or is there more to it.
because I am pretty sure these are isolated ground sockets


Correct. IG receptacles will be marked as such on the front. However, you could always check for conductivity between the ground and neutral with a meter.

edit:
Whoops! I F'd UP. The ground lug is usually connected to the receptacle's MOUNTING EARS! IG breaks this connection.


Last edited by Pooge on May 4th, 2020, 10:49 am, edited 1 time in total.

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