cable

http://cr4.globalspec.com/thread/39236/Earthed-Cables-and-Unearthed-Cables

Why do they repeat the threads?

The answers were there in the first thread itself.

And the second part - what is a cable voltage ?

A cable do not generate a voltage(or emf)- you can measure the voltage drop and that is simply by putting a voltmeter across it (or two on either sides)

Are you taking this type of earthed cable.

or this type of Unearth Cable

Please clarified

I m using the both cable

If you are using both of the two types of three phase cable pictured above DONT try and measure the voltage yourself as you don't seem to understand the basics of electricity and are therefore not qualified to safely measure lethal potential voltages by yourself. Death can easily result.

Please get a qualified electrician or electrical technician to do this for you before you accidentally kill yourself or someone else.

Down here, we don't call it "Earth cable" or "Unearth cable" as it confuses the electrical terms and definition. The picture on the top is called "Armoured Cable" and the Bottom cable is called "PVC/PVC Cable" Both cable has it own future.

Usage of both cables is the same, only the cost factor is different. The armoured cable will be slightly expensive than the PVC/PVC cable but in terms of weight, the PVC/PVC will be lighter than the armoured cable.

The armoured steel wire can be use as an earth cable back to your main power board and for your "Unearth Cable" or known as PVC/PVC you need to add another extra earth cable back to your main power board for earthing.

Then again, for mechanical protection and fire, the armoured cable is better than the PVC/PVC cable. Why ….. because the armoured steel wire that wrap around the cable give extra strength for the protect of the cable from mechanical damages.

In case of fire, the armoured steel wire still remained and we can identify the cable easily. For PVC/PVC cable, during the fire all the cable will be melted and join together and there is no way you can identify the cable, especially the multi core control cables.

That why, for the final cost saving the armourd cable still cheaper than the PVC/PVC cable in long run.

There are three major types of armored cable:

Aluminum Interlocked Armor is composed of a metal strip that is wrapped in a spiral around the cable. It is wrapped relatively loosely, so that the cable can maintain flexibility.

Continuously Corrugated Weld (CCW) is composed of an aluminum strip that is wrapped around the cable and welded together. The aluminum strip is then corrugated to increase the strength of the armor. This makes CCW impervious to moisture, liquid, and gases, though it is less flexible than Aluminum Interlocked Armor.

Teck 90 armored cable is similar to Aluminum Interlocked Cable except that it has a PVC jacket under the armor as well as over the armor. This gives the cable even better protection against physical and chemical damage from its industrial environment, without sacrificing flexibility. It is recommended for extreme operating conditions, in both wet and dry locations, in highly corrosive environments, and is resistant to mechanical abuse and ozone attack.

Omni Cable offers all three types.

Usually this terminology has become popular after XLPE cable generation.

EARTHED SYSTEM

An electrical system which fulfill any of following conditions:-

a. Neutral - point or mid - point connection is earthed in such a manner that , even under fault condition, the maximum voltage that can occur between any conductor and the earth does not exceed 80 % of the nominal voltage:

b. The neutral or middle point connection is not earthed but protective devices is installed which automatically cuts any part of the system which accidentally becomes earthed; OR

c. In case of ac systems only, the neutral points earthed through an arc suppression coil with arrangement for isolation within 1 h of occurrence of the fault for the non -radial field cables and within 8 h for radial cable, provided that the total of such period in a year does not exceed 125 h.

UN EARTHED SYSTEM

An electrical system which does not fulfill the requirement of the earthed system

Thank You