Phase conductor replacement?

[davro89]

I am an electrical apprentice and I've been given some questions to fill out for my portfoilo, however i cant find the answer to one of them and my mentor says he cant remember. Was wondering if anybody could help? bearing in mind that I've only been on the job for a month, im not sure if this is a stupid question. Apologies if it is. The question is:

When replacing any phase conductor, state the potential hazard that would occur if the component was incorrectly earthed?

 

[malcolmsanford]

As this question anything to do with capacitors?

 

[Electro-tech]

:56:bang !!!!

 

[davro89]

ok, could you elaborate please? electric shock, arc flash, damaged components?

 

[telectrix]

depends what you mean by component. metal case/backbox/containment ???

 

[davro89]

I really dont know, just in general terms? the question is written in the thread as it is in the question book.

 

[telectrix]

typical ambiguous question. OK. if any conductive component of an installation that should be earthed is not earthed, the immediate danger is electric shock, as such a component could become live under a fault condition.

 

[Knobhead]

The question is totally ambiguous, but if the equipment is inadequately earthed and you’re replacing a LIVE phase conductor your actually safer!

Lets start from the beginning.

To replace a phase conductor you start by disconnecting at the live end first if possible. You only have to worry about back feeds if it’s a 3ph supply. Disconnect at the now “dead” end. Replace the conductor in the reverse manor. You only have to deal with a live connection twice, disconnection and reconnection.

An old trick with metal clad switches was to remove any earth and then you could withdraw a live conductor without danger of a live>earth fault. OK the switch body was live for a moment while the conductor was withdrawn from the switch, but you knew it would be and didn’t touch it.

If you’re not trained to do live working answer the question with “ISOLATE SUPPLY FIRST”.

To be honest I think it’s a stupid question to ask anyone!