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Associate

Join Date: Dec 2007
Location: Kochi, Kerala, India
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Insisting Bare Earth Conductor

12/17/2007 8:12 PM

Is it necessary to insist Bare Earth Conductor for earthing of the power system as well as with lightning protections? In Indian Standards 3043/87, the color code for the protective conductor is being defined with clause 6.2.2, my concept to insist the Bare Conductor only for the above applications is spoiled. How you suggest? For example, in light wiring could we allow to run, the green color insulated earth conductor?

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Power-User

Join Date: Oct 2006
Location: Kolkata, India
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#1

Re: Insisting Bare Earth Conductor

12/19/2007 1:11 AM

Do you know why and where insulated earth conductor is used? Normally we use bare conductor in Swgr room, Motor earthing, Earth Ring, Lighting circuit. In some country insulated Cu conductor is used as Lighting ckt earth wire for a specific reason.

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#2

Re: Insisting Bare Earth Conductor

12/19/2007 9:18 AM

In the U.S., to my knowledge, the National Electrical Code does not require a bare earthing conductor, but it is allowed. I assume you are wanting to know for India, I'm sorry I can't help for that area.

Edit: I was referring to the earthing conductor at the service entrance or separately derived system, not the equipment earthing conductor that will be routed with phase conductors for lighting, convenience receptacles, etc.

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Guru

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#10
In reply to #2

Re: Insisting Bare Earth Conductor

12/20/2007 9:48 PM

Youngin,

A small but important correction: The earthing (grounding) conductor is the one which goes to the grounding electrode or is for equipment grounding, and carries current only in a fault condition. BUT: The earthed (grounded) conductor is what we call the neutral which is a current-carrying conductor in the circuit(s).

Regarding the posted question: The only advantage I know of in using a bare grounding conductor is to reduce the cross-sectional area of conductors in a conduit.

To minimize inductive coupling and its associated risk of sparks or increased impedance in fault conditions, wherever a service grounding conductor is run through steel conduit for physical protection of the conductor, it must be bonded to both ends of the conduit.

Regards--JMM

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#3

Re: Insisting Bare Earth Conductor

12/19/2007 10:45 PM

Do You know why NEC suggest insulated earth conductor?

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Associate

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#4

Re: Insisting Bare Earth Conductor

12/20/2007 12:06 AM

I ask, which will be better in safety aspects? Bare conductor or Insulated? I understand, most of the standards don't insist for any one. Both can be used. But, which will be better? I suggest, the bare one is better. What u say?

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#5

Re: Insisting Bare Earth Conductor

12/20/2007 12:21 AM

In case you use sensitive earth fault relay bare is no problem. But, insulated conductor will protect earth conductor from corrossion due to galvanic cell when it comes in contact to a dissimilar material.

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#6

Re: Insisting Bare Earth Conductor

12/20/2007 12:31 AM

In most countries bare earths have not been allowed for many years. Because they are dangerous as well as the corrosion problem. if you cant work out the common sense behind this regulation then maybe you should go back to school

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#7

Re: Insisting Bare Earth Conductor

12/20/2007 12:39 AM

Certainly using bare conductor when your earth conductor for lightning protection is used underground.

And in light wiring, the earth wire have to be coloured according to Indian Standards.

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Power-User

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#8

Re: Insisting Bare Earth Conductor

12/20/2007 1:01 AM

Hey, Basre conductor is normally used in Earth Grid. And while sizing a corrossion allowance is considered. But the Galvanic corrossion is mostly ignored.

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#9
In reply to #8

Re: Insisting Bare Earth Conductor

12/20/2007 3:36 AM

S Sir u r right, Bare conductor is normally used in Earth Grid and for lightning protection only. Other cases everything with insulated conductor only, the colour is either Green or Yellow-Green.

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