NEC Historical Question

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klillemo

Member
Location
Twin Cities, MN
My Brother-In-Law's household service drop is a typical three parallel overhead conductors to a mast above the roof. The neutral conductor terminates solely to a cable clamp on the EMT mast.
similar to this:
http://www.penn-union.com-Products-images-CATEGORY-medium-6949.jpg

The only down conductors are the two hot leads. Thus the neutral conductor to the meter box below is the EMT mast.

My question is, "Has this ever been an acceptible installation in the NEC?" The house dates to the early sixties.

Thanks
 
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480sparky

480sparky

Senior Member
Location
Iowegia
Your link doesn't work.

But if you're saying the EMT is being used as a neutral conductor, my gut reaction is that it's always been a violation.

I'd guess the clamp you are trying to display is for grounding the service to the grounding electrode(s)

Edit to add: Is this the clamp?

6949.jpg
 
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Pierre C Belarge

Pierre C Belarge

Senior Member
Location
Westchester County, New York
480sparky said:
Your link doesn't work.

But if you're saying the EMT is being used as a neutral conductor, my gut reaction is that it's always been a violation.

I'd guess the clamp you are trying to display is for grounding the service to the grounding electrode(s)

Edit to add: Is this the clamp?

6949.jpg
Click to expand...



I agree that most likely, raceways have never been permitted as a grounded conductor, especially PVC.;)
 
iMuse97

iMuse97

Senior Member
Location
Chicagoland
klillemo said:
This neighborhood was developed from the late 50's to present so this is a "modern" 110V/220V service.
Click to expand...

Thanks for the pic. Never saw it; original installer probably didn't have enough wire on the truck and made it work with what he had (temp. of course), and thought you'd be along soon enough to fix it.
 
L

lucky1974

Senior Member
Location
Michigan
Should be quick and easy fix, drop another conductor down mast and out weatherhead. Update grounding and your out of there. Maybe get some free beer out of it. Thanks for posting the pic. I've never seen that trick before.

I have never seen a drop that is 3 seperate conductors like that. All i have ever seen are triplex. Even 120 volt only service's are triplex with one leg taped back, luckily usually they are hooked up in utility transformer.
 
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B

bphgravity

Senior Member
Location
Florida
What is the hazard using the EMT mast as the grounded conductor between the service drop and the meter socket enclosure / service equipment verses actually having a "wire" in the raceway?
 
480sparky

480sparky

Senior Member
Location
Iowegia
bphgravity said:
What is the hazard using the EMT mast as the grounded conductor between the service drop and the meter socket enclosure / service equipment verses actually having a "wire" in the raceway?
Click to expand...

A grounded conductor, by definition, is a CCC. The raceway would not be.
 
roger

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
480sparky said:
Consider using EMT as a grounded (neutral) conductor. Run it through Art. 200 and see if it'll fly.
Click to expand...

If this service drop is under "exclusive control" of the POCO, Art 200 (or any NEC article for that matter) would not be applicable, see 90.2(B)(5)

Roger
 
480sparky

480sparky

Senior Member
Location
Iowegia
roger said:
If this service drop is under "exclusive control" of the POCO, Art 200 (or any NEC article for that matter) would not be applicable, see 90.2(B)(5)

Roger
Click to expand...

Not saying such a situations exists, but they don't 'round these parts. The triplex and the meter are the POCO's, and that's it.
 
B

bphgravity

Senior Member
Location
Florida
Maybe I should have asked the question this way.

What section of the NEC prohibits a metal raceway on the line side of the service disconnecting means to serve as the grounded service conductor?
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
bphgravity said:
Maybe I should have asked the question this way.

What section of the NEC prohibits a metal raceway on the line side of the service disconnecting means to serve as the grounded service conductor?
Click to expand...
Assuming that the raceway is on the load side of the service point, then this applies.
110.5 Conductors.
Conductors normally used to carry current shall be of copper unless otherwise provided in this Code. Where the conductor material is not specified, the material and the sizes given in this Code shall apply to copper conductors. Where other materials are used, the size shall be changed accordingly.
Click to expand...
Unless you are using copper conduit, you can't do it.:grin:
 
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