Grounding of IG receptacles

[llmay]

we recently converted several outlets to IG outlets.
As some 12/3 MC was handy and the red conductor was
not needed, we taped it as green and yellow where it was exposed and connected it to the orange IG receptacle.
The Green wire was used as a bonding wire for the box.
Is this a violation of the code? I can't seem to find where it is clearly addressed.

 

[bphgravity]

Re: Grounding of IG receptacles

yes, it is most certainly a code violation under most conditions. See section 250.119 of the NEC.

[ September 29, 2005, 03:54 PM: Message edited by: bphgravity ]

 

[petersonra]

Re: Grounding of IG receptacles

is MC a multiconductor cable?

if so, then exception B probably fits.

if not, you are out of luck.

can you use the armour to bond to the box and the green wire inside as your IG?

 

[iwire]

Re: Grounding of IG receptacles

Where the conditions of maintenance and supervision ensure that only qualified persons service the installation,

 

[petersonra]

Re: Grounding of IG receptacles

Originally posted by iwire:
Where the conditions of maintenance and supervision ensure that only qualified persons service the installation,

that would seem to apply to most situations where an IG would be found.

 

[iwire]

Re: Grounding of IG receptacles

Originally posted by petersonra:

Originally posted by iwire:
Where the conditions of maintenance and supervision ensure that only qualified persons service the installation,

that would seem to apply to most situations where an IG would be found.

Well Bob in this case I tend to agree with you, particularly in areas that require all electrical work to be performed by licensed workers.

I typically install IGs in office buildings, the paper pushers in those office building do not attempt to work on the circuits.

That aside many inspectors will hang you on that saying that only applies to places that employ full time electricians. Say a factory or other industrial type environment.

We used to remark the red to green quite often till the inspectors started getting sharp on that.

It is just another code section that leaves room for interpretation by the inspectors.


Another option is like you suggested, use hospital grade AC cable that has an insulated conductor for the IG and the sheath can used as a grounding conductor.

Most MC armor can not be used as an EGC.

 

[kiloamp7]

Re: Grounding of IG receptacles

Surprised that no one has asked - Why convert to IG? What kind of equipment really needs IG ?"

I believe there are several of us "IG haters" on this Forum.

 

[sheldon_ace]

Re: Grounding of IG receptacles

Originally posted by kiloamp7:
Surprised that no one has asked - Why convert to IG? What kind of equipment really needs IG ?"

I believe there are several of us "IG haters" on this Forum.

Well sometimes "we" don't have a choice when the engineer specs them. I still can't believe that people still put stock in IG recepts. I guess people just love to waste money on extra wire and more expensive devices. Its kind of funny, my CPU is plugged into a plain jane recept in my house, and it works just fine. I guess commercial buildings don't have good power.

 

[BruceH]

Re: Grounding of IG receptacles

Not an IG fan myself but yeah, there is certainly a much greater chance that a commercial building will have power quality issues when compared to your computers power source at home.

 

[petersonra]

Re: Grounding of IG receptacles

That aside many inspectors will hang you on that saying that only applies to places that employ full time electricians. Say a factory or other industrial type environment.

Where does it say that in the code???

No inspector has the authority to make up stuff like that.

 

[iwire]

Re: Grounding of IG receptacles

Bob they are not 'making stuff up'.

Where the conditions of maintenance and supervision ensure that only qualified persons service the installation,

That is vague and clearly up to the inspector to decide what exactly it means.

 

[petersonra]

Re: Grounding of IG receptacles

Originally posted by iwire:
Bob they are not 'making stuff up'.

Where the conditions of maintenance and supervision ensure that only qualified persons service the installation,

That is vague and clearly up to the inspector to decide what exactly it means.

With that logic they could say that whatever conditions of maint and supervision exist are inadequate no matter what.

 

[iwire]

Re: Grounding of IG receptacles

Yes I agree they could, and it would stick.

Don't forget I agree with your thought that most times where IGs are installed only qualified people will work on them.

Further what is the danger if someone mistakes a grounding conductor for a ungrounded conductor?

Now 12/2 MC IG cable is readily available so we use that, it has a green and a green with yellow.

 

[26member]

Re: Grounding of IG receptacles

my question is where are you terminating your IG ?
to be a truly isolated Grnd it must go back to the main service ,or transformer if seperatly derived system

 

[Leitmotif]

Re: Grounding of IG receptacles

OK looking to brain tap and improve my knowledge.

I have never had the joy of working this system and am not too sure if I should be relieved.

When this system was first cooked up - if I recall - it was to eliminate noise from motors on the ground (green) not grounded (white neutral).

So what I get here is
every receptacle box has two methods of ground - one the "regular ground" and the other the isolated ground.

both of these grounds go back to the grounding electrode system via the ground/neutral bus in main panel and via the ground bus in panels fed from the main.

So here is where I get a little confusd
they run together so what good does that do
is it not possible for noise to capacitive couple from the regular ground to the isolated ground in long runs?

I guess I could see it if the isolated ground was another ground connected to the same ground eletrode system) and ran by itself.

Otherwise does it really do any good?

The other question I have is using the armor on a cable for the isolated ground? Is that not the same as using conduit for ground with the same risks and more if there is a high fault current ie making those spiral wraps a heater?

BTW conduit used as ground islegal I know but I dont do it - if it breaks there goes your ground saw a kid killed from that - not on my job not on my watch.

 

[augie47]

Re: Grounding of IG receptacles

(from personra)

Where does it say that in the code???

No inspector has the authority to make up stuff like that.

Qualified Person. One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training on the hazards involved.
FPN: Refer to NFPA 70E-2004, Standard for Electrical Safety in the Workplace, for electrical safety training requirements.

add to that the comments in the handbook and clarification from 70E and theres no need for inspectors to "make up stuff", thank you.

[ October 14, 2005, 07:26 AM: Message edited by: augie47 ]

 

[26member]

Re: Grounding of IG receptacles

An isolated grnd would be using the orange recepticle ,so the ground slot is isolated fron the yoke of the recepticle and would terminate back at the neutral /ground bond at the source whether it be transformer of seperatly derived system or main service and is designed to carry faults from one peice of sensitive eqipment or other eqipment isolated from all other equip .that has an iso. grnd. This fault would not travel back up the common grnd but would try to go back to momma /the source that created it in the first place and dissipate on it's journey