Insulating equipment grounding conductors

jap

Senior Member
One could interpret this as it either has to be insulated, whether aluminum or copper.
or
just covered copper.


JAP>
 

jap

Senior Member
Otherwise it should read,

"Where livestock is housed, any portion of a direct-buried equipment grounding conductor run to the building or structure shall be copper and that conductor shall be insulated or covered.

JAP>
 

jap

Senior Member
When I started doing electrical inspections in 1990 I was at a mobile home park it was raining and I touched the metal siding of a mobile home and received a shock.

Later discussing the incident with the electrical inspector who was involved with the hiring of me, he said you could get shocked from touching a mobile home with the meter pulled, I looked a little confused and he said that’s one of the reasons they require an insulated equipment ground for the direct buried cable that supplies the mobile home.

Never forgot what he said, took me awhile to begin to understand why he said it.
An insulated EGC would not have kept you from getting shocked that day.
Something else was going on.

JAP>
 

david

Senior Member
Location
Pennsylvania
One could interpret this as it either has to be insulated, whether aluminum or copper.
or
just covered copper.


JAP>
I'm not sure I see how, I do see how you are reading it that way, I think it would need a comma for that to be true

the text says insulated or covered copper.

it seems to be indicting copper UF cable as one of the approved methods it does not read to include insulated Alum.
 

david

Senior Member
Location
Pennsylvania
I considered that reason... and it truly does not hold up in most cases. Could be it's in the Code because others think of it same as you. The only time it holds up is when an isolated ground is justified. We see how that concept of IG receptacles has been relegated practically to dust, but there are still a few justifiable cases.
if bare copper is buried in contact with soil could it pick up current and elevate the current on the equipment ground
 

jap

Senior Member
I'm not sure I see how, I do see how you are reading it that way, I think it would need a comma for that to be true

the text says insulated or covered copper.

it seems to be indicting copper UF cable as one of the approved methods it does not read to include insulated Alum.
But that doesnt tell you covered with what.
With reading it that way I could interpret it as covering a bare copper wire with dirt.

JAP>
 

jap

Senior Member
if bare copper is buried in contact with soil could it pick up current and elevate the current on the equipment ground
I would think that could happen regardless of whether a conductor was insulated or not.


JAP>
 

david

Senior Member
Location
Pennsylvania
But that doesnt tell you covered with what.
With reading it that way I could interpret it as covering a bare copper wire with dirt.

JAP>
Conductor, Covered. A conductor encased within material of composition or thickness that is not recognized by this Code as electrical insulation.
 

david

Senior Member
Location
Pennsylvania
Could we conclude that an insulated equipment ground is required in some applications such as a supply to a pool distribution panel for a measure of insurance that the equipment ground will not become part of the normal circuit current path?

In other words a covered equipment ground would be bare when a sub-panel is trimmed out.

And a insulated equipment ground would give some added measure in event that a equipment ground would touch a natural bus or touch another bare equipment ground.

And for underground portions of a circuit a insulated equipment ground gives an extra measure of assurance that a conductor in contact with soil currents will hopefully not become a path for stray currents.

It seems to be an attempt to insure under certain applications the equipment ground doe not mistakenly have currents elevated on that circuits bonding conductors
 

david

Senior Member
Location
Pennsylvania
Any voltage gradient would cause current to flow. Doesn't have to be large at all.
The list is extensive and how it is implemented varies in each respective article
RV parks
Manufactured homes
Boat yards
Natural bodies of water
Agriculture live stock buildings
Swimming pools ( outside motor branch circuits, underwater lighting , pool feeders)
and so forth

The list goes on, but a couple of things stood out, I’m not sure how the risk assessment was any different for manufactured home parks verses RV parks for direct buried conductors.

In other applications such as swimming pools, and If part of the goal was to prevent the equipment ground conductor contacting other conductors that may be a fault clearing path or a grounded circuit current path, why remove the insulation requirement when the conductor was indoors verses outdoors?
 
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david

Senior Member
Location
Pennsylvania
But that doesnt tell you covered with what.
With reading it that way I could interpret it as covering a bare copper wire with dirt.

JAP>
Jab you usually have insightful comments is there a point you are trying to make about covering the conductor with dirt?
 

david

Senior Member
Location
Pennsylvania
No.
Just still trying to figure out what your point is.


JAP>
OK
In a recent thread Dennis made some good points, on his understanding as to why he believed chapter three wiring methods did not need to be modified when dealing with an indoor portion of a spa application.

Which in return prompted me to go back through and look at the different applications of when the code requires an equipment ground to be insulated , insulated alum, insulted copper, covered copper verses allowed to be bare.
 

david

Senior Member
Location
Pennsylvania
No.
Just still trying to figure out what your point is.


JAP>
My point in part on a manufactured home installation for instants. An installer has a permanent foundation double wide setting on a block foundation. The service disconnect is on the structure mounted to the siding. The contractor runs SER cable to the manufactures homes distribution panel 75 ft under the homes in a crawl space.

At the inspection the installer / contractor is told he wasn’t allowed to use SER why because the code says insulated equipment grounding. The manufactures instruction say a feeder with a green insulated equipment ground.

The NEC in article 550 is specific enough to say the feeder equipment ground is not to be re-identified by baring the conductor, as an added measure to make it clear the equipment ground is to maintain its insulation even on the small portion that is being trimmed out and landed in the panel.

I’m not obligated to justify what the code says but it would be helpful when this correction is going to cost the installer hundreds of dollars to change I have a clearer understanding than the code says so.

This is applicable to when a installer runs copper UF cable to a pool pump, and they say the conductors insulated and I even ran it in conduit as an extra measure.
 

Smart $

Esteemed Member
Location
Ohio
...
In other applications such as swimming pools, and If part of the goal was to prevent the equipment ground conductor contacting other conductors that may be a fault clearing path or a grounded circuit current path, why remove the insulation requirement when the conductor was indoors verses outdoors?
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.
 

Smart $

Esteemed Member
Location
Ohio
M...
The NEC in article 550 is specific enough to say the feeder equipment ground is not to be re-identified by baring the conductor, as an added measure to make it clear the equipment ground is to maintain its insulation even on the small portion that is being trimmed out and landed in the panel.
...
I think this particular one is a matter of conformity with HUD regulations. Compliance with HUD is automatic because its regulations are a matter of federal law. The NEC at best is adopted at the state level.

PS: Don't quote me on that. I'm not 100% certain.
 

jap

Senior Member
My point in part on a manufactured home installation for instants. An installer has a permanent foundation double wide setting on a block foundation. The service disconnect is on the structure mounted to the siding. The contractor runs SER cable to the manufactures homes distribution panel 75 ft under the homes in a crawl space.

At the inspection the installer / contractor is told he wasn’t allowed to use SER why because the code says insulated equipment grounding. The manufactures instruction say a feeder with a green insulated equipment ground.

The NEC in article 550 is specific enough to say the feeder equipment ground is not to be re-identified by baring the conductor, as an added measure to make it clear the equipment ground is to maintain its insulation even on the small portion that is being trimmed out and landed in the panel.

I’m not obligated to justify what the code says but it would be helpful when this correction is going to cost the installer hundreds of dollars to change I have a clearer understanding than the code says so.

This is applicable to when a installer runs copper UF cable to a pool pump, and they say the conductors insulated and I even ran it in conduit as an extra measure.
The word "Insulated" comes up over and over above and would be more than enough clarification if one were to use it as a reason to make them change it out to a feeder with an insulated EGC.

In my opinion, although the EGC in UF may be covered by the outer insulation, it does not remain that way once it is stripped and therefore is not an insulated conductor.

JAP>
 
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