switch wire????

[sparky1502]

hello...i dont really understand the switch wire it being a permant live ,in a domestic lighting circuit. can some one explain it please...many thanks...sorry if it sounds like a stupid question

 

[diditrain]

If you only have one cable at your switch then one of the conductors is permanently live. The other one only becomes live when you flick the switch, enabling you to turn your lamp on and off

 

[peteludman]

are u a sparky?

 

[Graeme Harrold]

hello...i dont really understand the switch wire it being a permant live ,in a domestic lighting circuit. can some one explain it please...many thanks...sorry if it sounds like a stupid question

A stupid question is the one you don't ask..........

 

[sparky1502]

im a 2nd year trainee....just brushing up on my knowledge by asking a few questions..

i did a job the other week just moving a lighting circuit in the loft to make way for a new hatch...i pulled the fuse out ( rewireable fuses) put still got a belt..i thought i'd turned off the juice i also checked with my volt stick the onsite electrician said something about the neutral being fused too... the cu was a mangled mess.

 

[diditrain]

You need to brush up on safe isolation, locking off and checking for dead before you go any futher then young man if you want to live to a ripe old age

 

[sparky1502]

yes i thought the same thing as i got a pretty perm..but i thought that taking the fuse out cut the supply and ive only just started dont earthing and protection in college it confused me as to why the neutral would have to be fused as does not carry a load

 

[johnnyb]

Don,t trust those volt sticks in my opinion mate, them who checks and checks again live to test another day my freind, get a proper martindale tester could prove a very good buy for you .
A neutral is classed as a phase conductor, never take things for granted, you CAN get feed backs if the con/unit is incorrectly wired.

 

[Graeme Harrold]

Don,t trust those volt sticks in my opinion mate, them who checks and checks again live to test another day my freind, get a proper martindale tester could prove a very good buy for you .
A neutral is classed as a phase conductor, never take things for granted, you CAN get feed backs if the con/unit is incorrectly wired.

Neutral is a" live" conductor, not "phase", small terminology point, but one not to mess up in an exam. Even though neutral is connected to the center of the transformer and usually does not rise above earth potential, under fault conditions (or incorrectly wired) could become live................better safe than sorry, dont assume and treat as live as the phase.

Definately learn all about safe isolation, it will keep you alive. Dont take anyones word that something is dead, always check yourself............... After all its your fingers going in there!!!

 

[High Tower]

Supply goes through phase condutor, via switches etc, passes through end item, in this case the light bulb, and returns on the neuteral condutor.

If the termination of the neuteral condutor is incomplete or incorrect then the neuteral conductor remains at +230v in this case as its a single phase condutor.

if i was to speculate as to why you got a belt of a conductor on a "dead" circuit i would say the clue is in the post,

The CU is a state, and you were moving a supply on a landing. these two facts would most probably point to a case of borrowd nuteral, hence it was carrying a supply on a dead circuit.

Like i say this is only a gues.

Trick is to test nuteral conductors for voltage as if there is a fault as here then i will flag a voltage or remove all assosiated nuteral for the circuit from the board, which is the way they teach newbies at college.

I just personally opt for the test twice and be sure option.

Be safe fella

 

[EWebster]

Neutral is a" live" conductor, not "phase", small terminology point, but one not to mess up in an exam. Even though neutral is connected to the center of the transformer and usually does not rise above earth potential, under fault conditions (or incorrectly wired) could become live................better safe than sorry, dont assume and treat as live as the phase.

Definately learn all about safe isolation, it will keep you alive. Dont take anyones word that something is dead, always check yourself............... After all its your fingers going in there!!!

Volt sticks are worse than cigarettes for a quick death. Get a good continuity/volt tester and test all line and neutral wires.

You may have come across a borrowed neutral/shared line. Kill one circuit to turn the light off (generally the downstairs), but then there is a loop through from the live lighting circuit upstairs. In this case you need to pull two fuses to make the light fitting totally dead. Very common in 60s/70s houses for stair lighting.

 

[kung]

A stupid question is the one you don't ask..........

Agree 100% ! we all had to ask at some point and as said the stupid one is the one who doesnt ask and blows himself up !

 

[peteludman]

should u realy be working on electrics yet a neutral should not be fused or switched and did you pull the main fuse or just a lighting circuit fuse?

 

[johnnyb]

Corrected, graham, wrong terminology boys,

 

[Graeme Harrold]

Corrected, graham, wrong terminology boys,

Now you see what 2391 does to ya Cant keep my mouth shut now.

Walked into a local estate agent touting for inspection work, and just inside the front door within arms reach is a 10way CU.........bottom half broken off and no cover on the Line busbar!!!!!