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Re: IG receptacles [Re: George Little] #199855 03/11/11 08:36 PM
Joined: Jan 2004
Posts: 1,506
G
George Little Offline OP
Member
Thanks John, for your comments. I have total respect for MH's comments but I would argue that the reason for using an IG is to provide an alternate grounding path for fault current and a "clean" ground other than the raceway or cable jacket. The receptacle is not any better quality than a standard receptacle, the only difference being the bonding/grounding terminal is not fastened to the yoke. The inference that the receptacle's grounding terminal is connected by a direct insulated path back to the source is there. As a user, I expect when I see the orange dot or triangle that it is a circuit with an insulated grounding conductor back to the source. If this is not the case, don't us an IG.

Greg is correct in the ineffectiveness of the concept but the fact is, the orange dot is there and the need is to respect it.

Last edited by George Little; 03/11/11 08:39 PM. Reason: after thought:)

George Little
2017 / 2014 NEC & Related Books and Study Guides
Re: IG receptacles [Re: George Little] #199856 03/11/11 08:41 PM
Joined: Apr 2002
Posts: 7,151
HotLine1 Offline
Member
George:
Yes, I totally agree with you about the fact of someone being mis-led, and that a conductor is a better path for any fault current.

I have to sorta disagree with this..."The receptacle is not any better quality than a standard receptacle,"

Any IG I have seen or installed is 'spec grade'...and I will say that is much better quality then any 'standard' device.



John
Re: IG receptacles [Re: George Little] #199857 03/11/11 11:57 PM
Joined: Jan 2004
Posts: 1,506
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George Little Offline OP
Member
I stand corrected John, you are quite right about the quality of IG's, they are most likely "Spec" grade. Let's take this a step further- When we see a receptacle with a green dot on it we assume that it has redundant grounding and that there are two paths to ground- one is the raceway or cable jacket and the other is the green conductor tied to the green screw, bonded to the box and run back to the branch circuit source. The code even goes so far as to alert you if you install a hospital grade that is also an IG. The alert says that you don't have two paths to ground albeit it would be allowed.

So green dot means hospital grade and is required in Patient Bed Locations and areas where patients are treated in clinics and there are some pieces of equipment that require HG receptacles to mention a few. I know that some HG receptacles are installed where redundant ground is not speced out in the code but I also know that the green dot and orange dot or triangle are flags that say "special grounding".

517.13(B), 517.16, 2008 NEC

Last edited by George Little; 03/11/11 11:59 PM. Reason: Typo

George Little
Re: IG receptacles [Re: George Little] #199858 03/12/11 12:47 AM
Joined: Jan 2004
Posts: 1,506
G
George Little Offline OP
Member
Okay- You made me dig but I found it: 406.2(D)(1)


George Little
Re: IG receptacles [Re: George Little] #199859 03/12/11 01:00 AM
Joined: Apr 2002
Posts: 7,151
HotLine1 Offline
Member
George:

Debatable text...."(D) Isolated Receptacles. Where installed for the reduction
of electrical noise (electromagnetic interference) on the grounding circuit"

Perhaps this can be thought to mean IF the intent of the specific installation was for the reduction of electrical noise on the grounding circuit. The word 'shall' does not enter the paragraph until a sentence or two later.

Going back to your opening inquiry....was the church concerned about electrical noise?


John
Re: IG receptacles [Re: George Little] #199860 03/12/11 01:18 AM
Joined: Jan 2004
Posts: 1,506
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George Little Offline OP
Member
I don't know John, the words in (D)(1) are pretty convincing to me. And to answer your second question, No the church handyman just wanted to install quality receptacles.


George Little
Re: IG receptacles [Re: George Little] #199873 03/13/11 03:17 AM
Joined: Jan 2005
Posts: 315
L
luckyshadow Offline
Member
Article 406.2(D)(1) is where the violation can be found.
If there's
No isolated grounding conductor, then you can not install isolated ground receptacles.

Re: IG receptacles [Re: George Little] #199881 03/13/11 02:30 PM
Joined: Jul 2004
Posts: 9,455
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gfretwell Offline
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The flaw in that logic is "isolated grounding conductor" is not defined. In 250.146(D) there is a lot of permissive language about what you do not have to do but not much about what you have to do beyond providing an effective grounding path.

The green wire from the ground screw to the box meets all of those requirements.


Greg Fretwell
Re: IG receptacles [Re: George Little] #199883 03/13/11 04:47 PM
Joined: Jan 2004
Posts: 1,506
G
George Little Offline OP
Member
Greg- I respectfully disagree with you suggestion of using an isolated (in this case) insulated grounding conductor from the green screw of the receptacle to the box and saying that it qualifies as the system mentioned in 250.146(D). I know from your previous post that you have almost no confidence in the IG system for reducing noise on the grounding conductor of a circuit and I also know that a "clean" ground is what is being strived for but just jumping from the green screw to the box and relaying on the metal raceway for the expected IG circuit don't get it. Your sentiments do not distract from the code definition of an IG circuit and the requirements associated with an orange dot or triangle on the receptacle as is clearly called out it 406.2(D). Sorry for being so curt but the code is the code.


George Little
Re: IG receptacles [Re: George Little] #199902 03/14/11 04:08 AM
Joined: Jul 2004
Posts: 9,455
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gfretwell Offline
Member
I just do not see the code providing much language saying what you "shall do" for IG. I see a lot about what you can do. It is all permissive language.
Where does the code say the IG must land?

Quote
(D) Isolated Receptacles. Where installed for the reduction of electrical noise (electromagnetic interference) on the grounding circuit, a receptacle in which the grounding terminal is purposely insulated from the receptacle mounting means shall be permitted. The receptacle grounding terminal shall be connected to an insulated equipment grounding conductor run with the circuit conductors. This equipment grounding conductor shall be permitted to pass through one or more panelboards without a connection to the panelboard grounding terminal bar as permitted in 408.40,


This green wire was "run with the circuit conductors" for 6 inches wink

In the length of time we argued about this I am sure the EC could have taken out those $4 receptacles and put in some 49 cent ones and all would be good with the world.

Peace out.


Greg Fretwell
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