main power distribution earth and proprietary grounding

[rod gervais]

OK - there is nothing that should be confusing here......

Let's just deal with one group here - the rest would be the same - so no reason to get things cloudy because of multiples.

If you are using plastic or fiberglass boxes:

You have 4 outlets sitting one right next to the other - and all 4 are going to be powered from the same circuit breaker.

In order to install "star grounding" for these you will need the following:

From the breaker you will connect the "hot leg" - which you will daisy chain from one outlet to the next.

From the neutral buss on the panel you will connect one neutral leg - which you will daisy chain from one outlet to the next.

Now you will have to bring 4 individual ground wires - one from each outlet - back to tie into the electrical main grounding wire. You connect these to the receptacle ground.

You can bring these to a new box outside of the main panel - where they will tie to a grounding buss - and a single wire from that which will be tied directly to the ground wire between the main panel and the ground rod.

If you are using steel boxes things change a little bit:

You have to begin with Isolated Ground Receptacles. These have 2 separate points to attach ground wires.

The hot leg and neutral are the same as above.

There is a common ground wire that runs form the ground buss in the main panel - which you will daisy chain from one box to the next. You must also attach this to the body ground of the receptacle.

Now you will have to bring another 4 individual ground wires - one from each outlet - back to tie into the electrical main grounding wire.

The grounding in either case is the same.....

SO in the first case (Using non-metallic boxes and standard receptacles) you would have 6 wires required for the install - and in the 2nd (using metallic boxes and isolated ground receptacles) you would require 7 wires for 4 outlets.

Under no circumstance should you ever use a separate ground rod for this system......

I hope this helped simplify things.

Rod Gervais
GIK Acoustics
Director of Education
http://www.gikacoustics.com (USA)
http://www.gikacoustics.co.uk (Europe)
Tel.(US)1.888.986.2789
Tel.(UK)+44(0)20.7558.8976

[delfin]

Hi Rod!

my outlets are going to be plastic.

Now you will have to bring 4 individual ground wires - one from each outlet - back to tie into the electrical main grounding wire. You connect these to the receptacle ground.

sorry, i connect WHAT to receptacle ground and what do you mean exactly by receptacle ground?

You can bring these to a new box outside of the main panel - where they will tie to a grounding buss - and a single wire from that which will be tied directly to the ground wire between the main panel and the ground rod.

so, i ignore the third wire (grounding) in a cable that goes from breaker towards panel with 4 outlets in a row?
just like on my second picture in this thread, part b) ? [grounding2 copy.jpg]
i understood BriHar i can daisy chain this ground too, as distance is negligible?

so u are suggesting installing small panel just for these grounds and connect that ground buss via cable with main fuse panel ground buss?
only part i do not understand is what do u mean by "ground wire btw main panel and ground rod"? how we came now to the ground rod? are u referring to my extra rod digged into the soil?

SO in the first case (Using non-metallic boxes and standard receptacles) you would have 6 wires required for the install -

again, exactly like on mine second picture part b)? [grounding2 copy.jpg]

Under no circumstance should you ever use a separate ground rod for this system......

so, why u mentioned rode above?

please do not consider me as a bugger, i just really really try to understand.
can you please explain what would be wrong with situation as on my last picture [grounding3 copy.jpg] where ground is daisy chained? i always understood that only thing that matters is that we have only one SAME path to the ground.
now it seems that distance btw outlets is also important, i am just not sure how?

i did my "homework" and did read through various forums, but every now and then i find contradictory information's which confuses me even more.

and, at the end, do you and BriHar agree on this (see above) matter and i do not follow you guys, or you have opposing opinion?

thank you SOOOO much.

[BriHar]

OK, nice to see Rod popping in here.

I also have to question whether it is imperative that each outlet have a separate ground run back to the bus if they are physically side by side in a box. With a duplex outlet there are 2 outlets sharing the same physical ground terminal. I also look at this from a practical viewpoint and consider that powerbars are going to inevitably be plugged into these outlets. In fact my desk has powerbars built into it - maybe I've been lucky, but I've never had a problem. My last studio was a worst case - no ground wire at all all ground lugs on the outlets were bridged to neutral with jumpers. Well I took the bridges out, bolted a waterpipe ground lug onto a feedpipe of the radiator (I know, it should have at least been a cold waterpipe- but there weren't any in the room) and referenced each receptacle (duplex and triplex) separately back to this grounding lug (The integrity of the house ground and waterpipes was excellent according to an electrician who checked it out). From there, the rest was powerbars (also there was a UPS for the PCs and a Voltage regulator).

Anyway...
to your questions earlier Delfin,

1. I assumed this is what you will do, it makes the most sense.

2.we'll wait and see if Rod replies before making a definitive decision.

3. Since your conduit and boxes are plastic, then no you won't require the ground for this.

4. Do as your consultant suggested. Regarding the UPS, not necessarily for the audio circuitry, some of these can cause noise! Besides, why do you need UPS on the desk?. Best to use it only for the PCs, where it makes sense to do an automatic shutdown in a power outage. You might want to put a (good quality) power conditioner on the desk supplies though.

5. Nobody can answer that question definitively for you. It might, it might not. If in doubt, put them as far away as possible.

[BriHar]

Ah! Perhaps I missed Ron's point.
Did he mean:
In the 'group' box, bring four short wires from the ground terminal of each outlet and tie these to the ground wire of the 3 wire cable from the mains, using perhaps a marr connector?

[rod gervais]

OK - let's deal with language barriers if we can.....

The box is the container installed in the wall that the wires run into.

The receptacle is what you plug your gear into.

So when I say plastic or metal box - this is not referring to the receptacle........

Look below - this is a simple diagram for a star grounding system.

This diagram is what you would do if you were installing the outlets (receptacles) into plastic wall boxes.

ISOLATED GROUND SCHEMATIC.pdf

Rod Gervais
GIK Acoustics
Director of Education
http://www.gikacoustics.com (USA)
http://www.gikacoustics.co.uk (Europe)
Tel.(US)1.888.986.2789
Tel.(UK)+44(0)20.7558.8976

[rod gervais]

I also have to question whether it is imperative that each outlet have a separate ground run back to the bus if they are physically side by side in a box. With a duplex outlet there are 2 outlets sharing the same physical ground terminal. I also look at this from a practical viewpoint and consider that powerbars are going to inevitably be plugged into these outlets. In fact my desk has powerbars built into it - maybe I've been lucky, but I've never had a problem.

Bri,

Speaking technically (not practically) each individual outlet has an individual ground that runs back to the ground going to earth.

My example of 4 outlets side by each was just to attempt to make the illustration easier to picture.

However - from a practical point of view you could group outlets installed in a common box - althuogh I personally would not install the wiring in that manner......

That is *(after all) the whole concept of star point grounding - you spend additional money to purchase hospital grade I.G. receptacles specifically because they have a ground point (for the plug) that is isolated from the ground for the body.....

My last studio was a worst case - no ground wire at all all ground lugs on the outlets were bridged to neutral with jumpers. Well I took the bridges out, bolted a waterpipe ground lug onto a feedpipe of the radiator (I know, it should have at least been a cold waterpipe- but there weren't any in the room) and referenced each receptacle (duplex and triplex) separately back to this grounding lug (The integrity of the house ground and waterpipes was excellent according to an electrician who checked it out). From there, the rest was powerbars (also there was a UPS for the PCs and a Voltage regulator).

You got lucky is all I can say......

Not from a grounding (safety) point of view - but from a noise point of view.

The heating systems for homes, along with the water pipes - are required to be bonded to the electrical panel.

The water services are also often steel or copper feeds coming in to the building from underground - which means they are also a source to ground.......

Ground loops are caused by different sources to ground that have different potentiality.

It is because of the possibility of different sources to ground (within the same building) - and the different potential they have that we bother with star grounding to begin with.



Rod Gervais
GIK Acoustics
Director of Education
http://www.gikacoustics.com (USA)
http://www.gikacoustics.co.uk (Europe)
Tel.(US)1.888.986.2789
Tel.(UK)+44(0)20.7558.8976

[delfin]

hey guys,

thank you so much for your clarifications...
after long discussion today with my electrician, i think i will go with the scenario on my last pic...
i talked with 2 other studio owners and they confirmed that i should be fine with it...
i also explained all our conversation here...

regarding the water pipes...
in old houses, i can imagine that u can run into situation where metal pipe was somewhere "eaten" by corrosion... if that part is replaced, any grounding becomes a failure... so, probably one thing to check...

in new houses we are using now exclusively fancy plastic water-pipes with some even fancier protection shield (some foam)...

once again, thx so much...
if i run into additional doubts, i will feel free to ask...


cheers,

d.