Armour As Neutral

Why would you?

Never mind, I forgot who you were.

Go ahead, why not? What could it hurt?

Sure you can... Results = Dead people!

I doubt that any local Code, even yours, would allow this. But then, no one here knows every local Code.

The answer to the question is: house fires.

This doesn't seem to be an editorial comment or opinion. So I guess I should respond to your highness with all due dignity.

A sovereign can certainly do anything that amuses themselves. Any wiring configuration your highness chooses to use in your kingdom will certainly become the de facto standard for your realm. You may have some difficulty getting your electrical power to efficiently transfer across international boundries, but that will be the problem of the electrical engineers in your state department.

I humbly thank you for your insight, sire.

considered is

Can we use the armour of the cable as neutral line

The short answer is no as in many cases this totally defeats the purpose of the armour's function (providing an earthed barrier between the phase conductor and you).

what will be its side effects

It depends on the situation and the armour material (some are copper, others are steel). Short answer is anything from nothing up to and including jail time for second degree murder through gross negligence (or some similar charge).

Please read your applicable standards and don't do anything your not qualified to do.

actually the "Armour" is designed to do just that, be armour to protect the cable, to give additional mechanical strength, and NOT to be used as an earth.

It may be connected to earth, but many years ago it was dismissed as the primary earth due to certain failing in the cable glands and other reason that once researched anyone will find.

So yes it is an earth but not the MAIN earth... and the OP..... I am wondering what the next dumb question will be!

True, with regard to the standards (at least down here with our multiple earth neutral system) the armour both has to be earthed but not be relied upon as the primary earth (corroded steel after all makes a poor earth).

When you simplify it right down the whole point of the armour is to protect people who accidentally penetrate the cable so the conductive object (spade, digger, hand drill, etc) shorts the earthed armour to the phase and operates the protection disconnecting the supply and hopefully saving the life of the poor individual on the other end of the spade.

I don't believe this, I'm going to ask coolyaar a sensible question.

Do you mean armoured or concentric cable?

I still hope he's talking about concentric or wavecon cable. It looks like armoured but the outer strands are used as the neutral. Used a lot in the distribution industry for CNE systems. My house is fed by a concentric.

So YES you can use what looks like copper armours.

Split concentric in to a loop in loop out UK domestic service head.

Interesting.

Aren't the bare copper conductors wrapped around the outside of all the insulated conductors just under the outside encapsulation cover for the entire length of the cable to form a protective sheath/guard against accidental damage?

Well done.

All that needs to happen now is for the proverbial penny to drop somewhere near coolyaar.

In a concentric cable there's only one central line conductor surrounded by the neutral. Over this is a layer of insulation followed by the outer sheath.

Concentric top, split concentric bottom

Well I'll be.... Coaxial cabling for power distribution. Interesting, does it have any RF impedance specifications?

I'm not sure if I would call that armoured though.

Now that's an interesting one, the DNO's (District Network Operators) can bury them direct in the ground. They use both types but are going more for concentric now a days. A lot of the UK is gradually being changed to CNE or PME as it is here. Once the supply is past the DNO's service head and into the consumers realm only split concentric can be used. This is treated in the same manor as any household cable and must be installed to BS7671. Same cable, but now it can't be direct buried.

Rules for the big fish, but different rules for the minnows.

Do you want skin-effect heating?

I am just speechless!

Pool Yer Chain, he is! Yeah Pablo Sandoval! 3 Homers in three at bats!

and in English?

Listen to what Wikipedia says

• Do "we" want to be prosecuted when someone gets hurt/killed?
• Do "we" want to void the building insurance so that it will be a total loss when the fire takes place?
• Or do "we" want to put the correct cable in instead?

Ugh, er, oh, these are pretty tough ones. How on earth do "we" make decisions like that?

Dear Mr. coolyaar,

The Answer for you question is CERTAINLY "NO" and you should not use the Aramour as Neutral.

DHAYANANDHAN.S

Why would one, when there are other perfectly suited conductor cores inside the armour?

well there was a fire in a place where a technician did this and he asked me cause of fire and was this thing legal .my answer was NO.but everyone wants a technical answer. a simple NO is a word of stupid.so i said look these are side effects:

1: a net magnetic field due to the current in armour which will cause induction in other objects and noises

2: heating due to I2R effect because the armouring was SWA.i.e. a high resistance material

the voltage drop problem was not big enough because once earthed the whole armour will be at ground potential even if carrying current.

so he was satisfied and i explained the cause of fire to be my point 2.

i know the answer is NO but please explain with logic (technical) and not be like a parrot.codes and standards have a huge technical background behind their every regulation .it is not a big deal to memorize the paragraphs of standards but it is more important to dig into the logic behind everything i.e. the scientific reasons behind the rules of standards and codes.

<...once earthed the whole armour will be at ground potential even if carrying current....>

WALOOB. How is that possible, if the armour has resistance, please?

How is the neutral to be connected to the banjo washer outside the terminal box glanding without compromising the ingress protection rating of the box?

Which conductor is to be selected for the earth/ground conductor, if it isn't the armour?

Why not send the phase down the armour instead?

So we know that the armour of a cable cannot be used as the neutral. We have established it can be contributory to fires and loss of life.

You don't give us a clue as to the size of make up of the cable.

The cable armour would have to be electrically rated to carry the same current as the phase conductor. Maybe on the very small cables but generally the armour resistance on a cable is a magnitude higher. This will cause the armour to heat.

You can get a voltage on neutral - you can no longer consider it as electrically dead.

If you have a voltage on neutral and then it gets earthed down in the field how much current is passing through it?

There are many reasons but as early posts its a no no. The armour is there to protect the cable and usually provide an earth return sufficient to bring out the circuit protection whether it be the fuse/breaker or an RCD.

I shutter to think of the plant where technicians, ignorant of basic codes which were created primarily for fire and personal safety, are free to make installations of their own design. Then the engineer is put in the position of defending the code to the technician's satisfaction. It also concerns me that you omitted electrocution as one of the possible 'side effects'. If its no big deal to memorize the paragraphs of standards, you should try having your technicians do so before they kill somebody.

NO......

I think the OP has "runn oft". (From the movie Oh Brother Where Art Thou?)

He'll be back. Thick skined is our coolyaar!

NO!!

If you do this you are exposing anyone and everyone to extreme danger of injury and/or electrocution (death) that comes in contact with the cable and/or any equipment the cable is attached to.

The armour is there to protect the cable conductors from incidental physical damage during installation and while in service.

It is not ever supposed to carry current from any source.

Thanks for asking :)

Neutral does carry current in most cases and is your wire or amour, impedance from ground.

If you contact neutral with your bare hand, you will most likely have elctrical current pass through your body with the same probability as contacting a "hot" conductor.

I am available for consultation to define safe solutions, with over 25 years of safety experience.

In one specific situation that I am aware of you may do something akin to using the armour as a neutral... http://www.gcdt.com/2-0.cfm

or http://www.youtube.com/watch?v=v2KmxOs0WzA&feature=relmfu