Isolated Ground
- Thread starter rsvetti
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sceepe
Senior Member
Re: Isolated Ground
Makes people feel better. IMO it really doesn't do much. Theory is that you can reduce unwanted voltage (noise) on the ground. Theoretically this may improve the performance of sensitive elctronic equipment.
You have to bond all metallic parts likely to become energized to the equipment grounding conductor at some point. IMO Electrically it is all connected. You are just keeping them separate from the outlet to the service. I have my doubts as to whether the extra cost involved gives you much benefit.
Sidebar, I love seeing a place full of orange IG recpts and looking in the feeding sub panel to find the ground bar bolted to the back of the can.
I advise folks to save their money on the IG recepts and get a good TVSS on the panel.
Makes people feel better. IMO it really doesn't do much. Theory is that you can reduce unwanted voltage (noise) on the ground. Theoretically this may improve the performance of sensitive elctronic equipment.
You have to bond all metallic parts likely to become energized to the equipment grounding conductor at some point. IMO Electrically it is all connected. You are just keeping them separate from the outlet to the service. I have my doubts as to whether the extra cost involved gives you much benefit.
Sidebar, I love seeing a place full of orange IG recpts and looking in the feeding sub panel to find the ground bar bolted to the back of the can.
I advise folks to save their money on the IG recepts and get a good TVSS on the panel.
lady sparks lover
Senior Member
Re: Isolated Ground
Lady
[ September 01, 2005, 10:21 AM: Message edited by: lady sparks lover ]
I think it is a waste too. I haven't see any effective changes. I believe the TVSS does a better job too, so I have stopped putting in the IG ground. Only if it's heavy duty equipment!
Lady
[ September 01, 2005, 10:21 AM: Message edited by: lady sparks lover ]
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: Isolated Ground
Isolated ground receptacles had a place in the early days of computers. They were especially helpful for noise sensitive parallel or serial RS232 interconnections between computers and peripheal devices. The interconnection cable was usually shielded, so the were many ground loops created and the isolated ground system helped make them manageable.
In today's age of unshielded interconnections (i.e. ethernet) isolated grounds serve no purpose other than to say "I don't know anything about the correct application of the products I specify".
Isolated ground receptacles had a place in the early days of computers. They were especially helpful for noise sensitive parallel or serial RS232 interconnections between computers and peripheal devices. The interconnection cable was usually shielded, so the were many ground loops created and the isolated ground system helped make them manageable.
In today's age of unshielded interconnections (i.e. ethernet) isolated grounds serve no purpose other than to say "I don't know anything about the correct application of the products I specify".
Re: Isolated Ground
As Jim has correctly stated it is mostly a hold over from the early computer days when signal cables used ground as part of the signal path. With the development of ethernet and optical modems, IGR has become obsolete for the most part.
FWIW the IGR was developed to help prevent common mode noise from entering a ground circuit. However it is not capable of cleaning up any type of noise. Only somehing like a isolation transformer can do that.
As Jim has correctly stated it is mostly a hold over from the early computer days when signal cables used ground as part of the signal path. With the development of ethernet and optical modems, IGR has become obsolete for the most part.
FWIW the IGR was developed to help prevent common mode noise from entering a ground circuit. However it is not capable of cleaning up any type of noise. Only somehing like a isolation transformer can do that.
electricmanscott
Senior Member
- Location
- Boston, MA
Re: Isolated Ground
The orange receptacles are pretty nice.
The orange receptacles are pretty nice.
cselectric
Senior Member
- Location
- Wisconsin
Re: Isolated Ground
They don't seem overly useful, despite which I've not had much success in talking engineers out of spec'ing them.
They don't seem overly useful, despite which I've not had much success in talking engineers out of spec'ing them.
Re: Isolated Ground
At the risk of running everyone off I'm going to post my two cents worth anyway or at least it seems like I tend to run everyone off and don't know why, some times I get arrogant and often wrong but so are most on here at times.
I agree that with a two wire 120 volt circuit it doesn't do much good to have a separate equipment ground but it does with a 240 volt or a multi circuit with more than one hot or ungrounded circuit.
Please click here to see why
Ronald
[ September 05, 2005, 01:04 AM: Message edited by: ronaldrc ]
At the risk of running everyone off I'm going to post my two cents worth anyway or at least it seems like I tend to run everyone off and don't know why, some times I get arrogant and often wrong but so are most on here at times.
I agree that with a two wire 120 volt circuit it doesn't do much good to have a separate equipment ground but it does with a 240 volt or a multi circuit with more than one hot or ungrounded circuit.
Please click here to see why
Ronald
[ September 05, 2005, 01:04 AM: Message edited by: ronaldrc ]
- Location
- Massachusetts
Re: Isolated Ground
Morning Ronald, I don't think you will be running anybody off.
That is not the issue this thread is discussing.
This thread is about an additional insulated grounding conductor run with the rest of the circuit conductors but electrically isolated. It originates at the main bonding jumper and runs electrically isolated all the way to the utilization equipment.
Morning Ronald, I don't think you will be running anybody off.
Well as you know that would be an NEC violation in either case. Nice drawings though.
That is not the issue this thread is discussing.
This thread is about an additional insulated grounding conductor run with the rest of the circuit conductors but electrically isolated. It originates at the main bonding jumper and runs electrically isolated all the way to the utilization equipment.
hardworkingstiff
Senior Member
- Location
- Wilmington, NC
Re: Isolated Ground
I love it! I just had to put this up again.
Re: Isolated Ground
Hello Bob
I have not been following the post that close. But in this particular thread I read this as a question about the equipment ground and not a dedicated ground.
But either way I wanted to point this out about multiple ungrounded circuits and why you should have a separate equipment grounding conductor.
And even with a two wire 120 volt circuit I agree with the NEC it also should have a separate grounding conductor, because with the multi three wire or so called split circuits in dwellings using a common neutral with 2 ungrounded conductors.Otherwise there would be arguments even worse than we have now about where and why we should have one.
The other reason you pointed out to me in your private message is the one that is brought up most in discussions on this subject.
Please explain it.
Ronald
[ September 05, 2005, 11:21 AM: Message edited by: ronaldrc ]
Hello Bob
I have not been following the post that close. But in this particular thread I read this as a question about the equipment ground and not a dedicated ground.
But either way I wanted to point this out about multiple ungrounded circuits and why you should have a separate equipment grounding conductor.
And even with a two wire 120 volt circuit I agree with the NEC it also should have a separate grounding conductor, because with the multi three wire or so called split circuits in dwellings using a common neutral with 2 ungrounded conductors.Otherwise there would be arguments even worse than we have now about where and why we should have one.
The other reason you pointed out to me in your private message is the one that is brought up most in discussions on this subject.
Please explain it.
Ronald
[ September 05, 2005, 11:21 AM: Message edited by: ronaldrc ]
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