I just had an inspector call me and he had inspected a job at a church where the handyman had replaced all the two wire receptacles with IG's (orange Dot). This an EMT job and the contractor installed a jumper wire between each receptacle green screw and the box. Inspector asked me if this is a violation? I said yes, what say you?

110.3(B)? It is not really "IG" anymore but I am not sure that is a violation.
When I read through the articles that talk about IG, they just permit you not to bond to the enclosure (going as far back as the MBJ bus bar without a connection). I don't see anything that prohibits it.

George:
I have to agree with Greg. It's not an 'IG', but it is compliant with the jumper and the EMT.

The green screw ground path is via the jumper to the box & EMT, and the 'isolated' mounting yoke is bonded via the mounting screws.

I guess $$$ was not a factor for the 'handyman'?

What basis do you say it's a violation...110.3 (b)?

110.3(b) for sure. When see an orange dot or an orange triangle on a receptacle a user expects he/she is using a circuit that has a isolated ground and this may be critical to the equipment being used. I like the comment about $$$ not being an issue. It's just something that is not up to my standard. I've been whacked before for winking at common sense things. Yes I know it's not a fire or shock hazard but I'm writing it.

George:
Yes, it's your call, & 110.3 (b) is the way to go.

I think IG is largely snake oil and the "standard" of what IG really means is so loose (isolated to the first panelboard or all the way back to the service disconnect?) that I am not sure how you really write it up but it is clear that there is nothing "isolated" here.

:opinion bit on:
My take on IG is "fix your box and your problem will go away". I have seen people make electricians jump through lots of hoops before they finally fix the real problem. Usually they do not admit that all of the electrician's toil was wasted effort.
A failure caused by "noise" is a symptom not a cause.

Greg:
Back some years IG was a 'spec' for computer equipment, as I'm sure you know. Lately, I only see it for some POS equipment.

That said, it has been a royal pain as to how to install the IG to satisfy everyone involved. I had a few way back that REQUIRED a driven grd rod in the 'spec', to which the AHJ laughed, and we 'bonded' that 'rod' to the other GEs in the facility. That job was for a 'data' rack back in the mid 70s.

Many jobs later, the kinks were worked out...and back to the main with the "IG"!

IBM dropped IG as a requirement sometime in the early 80s when they figured out it was not really accomplishing anything. Unfortunately old habits die hard and I still hear people say it is required.

The only thing I see is 110.3 (b) too. The receptacle is installed as it is listed.

George:
Some commentary from an article in ECM, comments by MH, only a portion of herein:

"Per the Code, the grounding terminal for an IGR could terminate to the metal outlet box that contains it (Figure, point C). The NEC doesn't dictate where you terminate the grounding terminal for an IGR — just that you terminate to an effective fault current path. Nor does the NEC require each IGR to be on its own dedicated branch circuit.

However, the Code does require you to ground the metal enclosure. This is automatic with a regular receptacle; you must provide an additional grounding means when using an IGR (unless you bond the enclosure to the IGR). The Code does not permit you to use interlock, or standard, type MC cable when wiring an IGR because the outer interlock sheath is not recognized as an effective fault current path to ground metal enclosures. However, you can use AC cable with an insulated equipment grounding conductor, because type AC cable armor is listed for use as an equipment grounding conductor."

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.

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.

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

Okay- You made me dig but I found it: 406.2(D)(1)

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?

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.

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.

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- 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.

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?



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

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.

Canadian Code is pretty clear...

10-906
(7)In the case of metallically enclosed systems where the grounding path is provided by the metal enclosure,
a bonding jumper shall be installed to bond the grounding terminal of the receptacle to the enclosure.

(8) Notwithstanding Subrules (6) and (7), the bonding jumper, in the case of receptacles having grounding
terminals isolated from the mounting strap required for special equipment, shall be permitted to be
extended directly back to the distribution panel.

It still says "shall be permitted" not "shall extend to"

Greg- I'm starting to think that you aren't in favor of having a insulated and isolated grounding conductor run back to the source. I hope that's not why you are objecting to use of the concept. The fact remains if you see an orange triangle on a receptacle don't you expect that the installer has run a insulated grounding conductor back to the source- because if he didn't he/she has defeated any benefit that might be there with an IG circuit. One can dispute the benefit for sure and I have my doubts on the benefit or need for such an installation. You've had more experience than I have because of your exposure to the computer facet of our industry. Maybe the benefit is dubious at best but the circuit should be installed as having a clean ground based on the orange triangle. That's, as they say "My Final Answer".

I am just saying the code does not define "isolated ground" nor does it have any "shall do" language.
Everything is just permissive language allowing you to avoid normal practice if you want to.

George:

Just a quick FYI, from the 2011 NEC changes.....
517.16 revision IG receptacles are no longer permitted.

517.13 (B) was revised also.

AHHHHH

So I 'shall be allowed'.... (but I shall not have to).

Isolated from as many mechanical connections as possible, is about as 'isolated' as a ground CAN be, until it fails. Cause ground is ground, until it isn't.

That's why I said 'pretty clear', and not 'clear'

Since I'm 'allowed' to now..... I think it would be better to use a standard receptacle and a separate physical bond wire extended back to the panel. This would ensure that if there was a mechanical ground failure (emt come loose etc), the separate bond wire would become the least resistive path to ground.
With an isolated ground receptacle and a failed mechanical ground, the potential differece imposed between the now open ground on the yoke, and the solid grounded bond wire, could be more harmful to equipment.

I can't find Isolated ground anywhere else in the code but what I posted.... and that language (once pointed out to me) is pretty obvious.

Pool:
Be careful here...what you read within the debate with George, Greg, Luckyshadow, & myself is based on NEC! And our interpertations, which you can see differ. We are NOT referencing the CEC!

The IG rule in 250.146(D) is simply permission not to follow the general practice of bonding the EGC every time you get a chance. It does not relieve the requirement that you have an effective bonding path back to the main bonding jumper but it allows you do do this with a home run of insulated wire, not landing anywhere in between but I see nothing that prevents you from landing that wire at any convenient bonding point along the way.
Would you fail this if the IG landed on the EGC bar in the load side distribution panel? (a common thing in computer room wiring where the "star ground topology" starts at the sub panel feeding the data center.

And yet one more reason to not hang on every word MH says. I am aware that the NEC does not specify how to terminate an IG grounding terminal, after all it's not a design manual. We were told that from the start. But if you see a orange triangle on a receptacle, you don't expect conventional grounding, at least I don't. So what's so special about having an insulated jumper from the grounding terminal on an IG to the box it's installed in? The 6" long jumpers that we've used for years did that. So whether one believes in the IG concept or not the issue become what the design professional specifies on the plan. I'm betting on an insulated wire back to the source just like our Canadian brothers have it in their code.

Gotcha.
I'm a sucker for debate... and I ain't into learning how to find my way through a different maze
Though I'm sure they are very similar.

http://ecmweb.com/mag/electric_pros_cons_ig/