250.64 GEC Raceway

[crossman]

Tom, I see what you are saying. I suppose the flex could be looked at as a transformer winding, sort of like a shorted CT around the GEC.

Does anyone know of any links to studies of this "choking" phenomena? I just don't believe that 3 feet of flex is going to have any appreciable affect on the amount of current flowing in the GEC. Does a CT have any appreciable affect on the current in a phase conductor? Even with 1000 amps or more flowing?

 

[tryinghard]

I think the best GEC is one that is open, most often these are not in an environment that allows damage.

 

[stickboy1375]

I don't know that BX is cable armor. I don't know of anything which is directly referred to as "cable armor". The question becomes "what did the NEC CMP mean when they used the term "cable armor".

Also, when would we ever use bx (AC cable) as a GEC? Single conductor armored ground? I never thought of that as being AC cable. Is it?

I know older services use to use cable armor, basically #8? solid cu wrapped with a metal flexible jacket. Not sure if they make the stuff anymore.

Can you give me a code section on that please?

250.64 (E)

 

[crossman]

250.64 (E)

I don't see that 250.64(E) requires a bonding bushing and bonding jumper. All it requires is bonding, and the locknut and fitting do that.

 

[M. D.]

I think they mean this stuff ,.the cable is the copper and the steel stuff around it ,which could be referred to as cable armor I suppose

http://www.southwire.com/ProductCatalog/proddetail.jsp?htmlpreview=true&token=261&desc=Duraclad%20Type%20BAG%20Bare%20Armored%20Ground%20Cable

 

[stickboy1375]

I think they mean this stuff ,.the cable is the copper and the steel stuff around it ,which could be referred to as cable armor I suppose

http://www.southwire.com/ProductCatalog/proddetail.jsp?htmlpreview=true&token=261&desc=Duraclad%20Type%20BAG%20Bare%20Armored%20Ground%20Cable

Thats what I think of when I hear cable armor.

 

[crossman]

We used that stuff for residential services. We called it "armored ground". When the CMP says "cable armor" it implies armor that you can install a cable into. But maybe they are talking about the stuff in the pic.

 

[engy]

The code does not allow FMC to enclose a GEC as the spirals are not shorted out as in AC cable and create an choke.

The stuff in post#25 is copper conductor in FMC.

 

[M. D.]

The stuff in post#25 is copper conductor in FMC.

No, it is not . It is ;

[FONT=Arial, Helvetica]

[FONT=Arial, Helvetica]Southwire Duraclad? Bare Armored Ground Cable is suitable for use as a grounding electrode conductor for Residential Service Systems.[/FONT]

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