Insulating equipment grounding conductors

[jap]

on a lighter note, if your buddy was right about getting shocked by the apparent gradients that were available even with the meter pulled, I'd tell the home owner to capitalize on that. Lay a couple of insulated conductors along side that non insulated EGC and run their lights for free....


JAP>

 

[david]

on a lighter note, if your buddy was right about getting shocked by the apparent gradients that were available even with the meter pulled, I'd tell the home owner to capitalize on that. Lay a couple of insulated conductors along side that non insulated EGC and run their lights for free....


JAP>

No, he never thought that, most likely it was a neighbors extension cord and someone rigging temporary power to the mobile home.

The incident led to a discussion on the metal siding and the measures the NEC took with the four wire supply and the insulated equipment ground. Remember back then three wire supplies where common to outbuilding garages and such.

 

[david]

My guess is first it's not that it's indoors but more that it is not underground (i.e. in direct contact with earth).

But like I said, the whole insulated (as in not for corrosion protection) thing doesn't stand up to argument. For example, we are permitted to install an auxiliary grounding electrode (even a grounding grid) connected to an EGC... anywhere! How would electrically insulating/isolating the EGC from dirt earth be beneficial if you have an electrode bonded to both ends of said EGC?

More to your point, isolated equipment grounding is the only purpose I can justify an insulated EGC. To otherwise isolate from being a fault clearing pathway for another circuit seems self-contradictory to me.

It is not un-common for me to see bare equipment grounds in sub-panels touching or nearly touching a nuetral buss by the way the equipment grounding conductors are strung through a panel.

I would think that would be a reasonable concern in some of the applications where a insulated ( not bare / or covered) equipment grounds are being required.

 

[user 100]

It is not un-common for me to see bare equipment grounds in sub-panels touching or nearly touching a nuetral buss by the way the equipment grounding conductors are strung through a panel.

I would think that would be a reasonable concern in some of the applications where a insulated ( not bare / or covered) equipment grounds are being required.

I don't agree- imo, that's merely reflective of a poor installation.

There is nothing wrong with the bare egc's found in nm- the product itself is fine when applied correctly. If someone isn't capable of routing egcs away from a neutral bus, or anything current carrying, then they had no business in the panel to begin with.

 

[jap]

No, he never thought that, most likely it was a neighbors extension cord and someone rigging temporary power to the mobile home.

The incident led to a discussion on the metal siding and the measures the NEC took with the four wire supply and the insulated equipment ground. Remember back then three wire supplies where common to outbuilding garages and such.

I'm startin to understand where your comin from now.

Although the biggest plus to the 4 wire install was the separation of the Grounded Conductor from the EGC or non current carrying parts of a structure,,, not so much whether the EGC was insulated or not.

JMO.

JAP>

 

[Smart $]

It is not un-common for me to see bare equipment grounds in sub-panels touching or nearly touching a nuetral buss by the way the equipment grounding conductors are strung through a panel.

I would think that would be a reasonable concern in some of the applications where a insulated ( not bare / or covered) equipment grounds are being required.

Yes, that is a reasonable concern... but if not all the EGC's in that panel are required to be insulated, how is one here and there going to help?

 

[jap]

It wont.

Maybe they should just start making an insulated cover that will snap over the neutral bar and quit picking on the EGC.

JAP>

 

[Smart $]

It wont.

Maybe they should just start making an insulated cover that will snap over the neutral bar and quit picking on the EGC.

JAP>

:lol:

That's not going to happen any time soon. I think these are the cases that rely on workmanship for compliance.

 

[jap]

I'm lookin for solutions here smart,,,,, and your not helpin....

 

[user 100]

It wont.

Maybe they should just start making an insulated cover that will snap over the neutral bar and quit picking on the EGC.

JAP>

That's not going to happen any time soon. I think these are the cases that rely on workmanship for compliance.

:thumbsup:

 

[david]

I don't agree- imo, that's merely reflective of a poor installation.

There is nothing wrong with the bare egc's found in nm- the product itself is fine when applied correctly. If someone isn't capable of routing egcs away from a neutral bus, or anything current carrying, then they had no business in the panel to begin with.

True nothing would eliminate that concern better than good workmanship.

I still think it is in part why an insulated equipment ground is required for pool feeders and a some other applications.

The authors and panel members are aware that not all feeders are for underground applications

 

[jap]

I think it'd be safe to say when something is specified to be insulated that the intention is to keep the conductor from touching something else regardless of what that something else may be.


JAP>

 

[Smart $]

I'm lookin for solutions here smart,,,,, and your not helpin....

From my perspective I am a helpin'... :angel:

 

[tortuga]

551.80 Underground Service, Feeder, Branch-Circuit, and Recreational Vehicle Site Feeder-Circuit Conductors.
(A) General. All direct-burial conductors, including the equipment grounding conductor if of aluminum, shall be insulated and identified for the use.

There are several examples with- in the NEC where the equipment grounding conductor is required to be Insulated.

Here is one I found to be peculiar , I say that because it doesn’t fit the explanation I give when I am asked why the equipment ground has to be insulated. Or why can’t I use UF cable, NM cable or SER cable.

I know what my explanation is for why the insulation of the equipment ground conductor what’s yours ?

The requirement for not stripping the ECG was added in 550-24 in the 1990 NEC.
Two proposals were discussed, the first one 1214-2 has the best explanation for the rejection that the insulated ECG provides needed protection during high voltage ground fault.

From the 1989 ROP

Log # 1214-2
19-46-(550-24, Exception-(New): Reject
SUBMITTER: Bill . Shanks, Perrysburg, OH
RECOMMENDATION: Add:
Exception: Aluminum or copper-clad aluminum without
individual insulation where part of a cable assembly,
or bare copper, shall be permitted for the equipment
grounding conductor, when installed in a raceway for
permanent installation.
SUBSTANTIATION: As an inspector, I see this all the
time in mobile home parks. I feel this is just as safe
as an installation. The integrity of the equipment
ground is still maintained and protected from physical
damage.
It's very hard to tell an owner to take this out and
put in an INSULATED equipment ground when it serves the
same purpose.
PANEL ACTION: Reject.
PANEL COMMENT: A bare equipment conductor would
provide multi paths for fault currents. Ground
continuity is very critical because of nature of
structure.
Insulation reduces arcing between equipment grounding
conductor and other grounded equipment during a fault
condition.
Integrity of grounding conductor is preserved by
being insulated.
VOTE ON PANEL ACTION: Unanimously Affirmative.

19- 47 - (550-24): Accept
SUBMITTER: CMP 19
RECOMMENDATION: Revise Section 550-24 to read:
"Mobile home feeder conductors shall consist of
EITHER a listed cord, factory-installed in accordance
with Section 550-5(b) or a permanently installed feeder
consisting of four continuous, insulated, color-coded
conductors which shall be identified by the factory or
field marking of the conductors in compliance with
Section 310-12. "Equipment grounding conductors shall
not be identified by stripping the insulation." (Added
material in quotations.)
SUBSTANTIATION: To clarify that the feeder to a mobile
home is intended to be either a listed supply cord or a
permanently installed feeder and not both, Also to
clarify that it is not the Panel's intent to permit
bare equipment grounding conductors or to have the
insulation stripped to identify the conductor.
PANEL ACTION: Accept.
VOTE ON PANEL ACTION; Unanimously Affirmative.