Line, Live and Phase

[louisIV]

Hi folks.

I'm in my second term of 2330 and am getting on pretty well I think. I've got this question which I haven't found a good opportunity to ask in our theory lessons, but maybe someone can clear this up for me.

Up to now, the terms line, live and phase seem to have been used pretty interchangeably. I can't help feeling that they shouldn't be. What's the correct use of these terms?

Thanks!

L IV

 

[revjames]

As far as I know 'Live' refers to any conductor carrying current in normal conditions ie L, N. Line is a cable with potential, ie one that is live in the 'live' sense and Phase refers to either L1, L2 or L3 in a multiphase situation.

Probably havent worded it well, don't worry there will no doubt be a more informative answer soon!

 

[Andy™]

used to be live. then got changed to phase, which then got changed to line in 17th.

'live' now refers to anything that carries current, so both 'line' & 'neutral' are both 'live' conductors

 

[SPECIAL LOCATION]

First place of reference is the Definitions Part 2 BS7671.

pages 26 7 27 .. you will find them

The interchangeability and confusion comes because the 17th edition changed the definitions..

In the 16th edition the "Phase" conductor was the one connected on the fuse side of the circuit.

In the 17th it is now call the "Line" conductor!

Live conductors are all conductors that can be energised while a circuit has power applied to it.

e.g. basic light circuit MCB up Line conductor through switch to bulb.

then back down a neutral conductor to the neutral bar of the cu.

IF you took the neutral cable off the neutral bar..

the neutral conductor will be at 230v with respect to earth/neutral

Thus the 'Line' and 'Neutral' conductors are both LIVE conductors making part of the normal circuit.

"Phase" strictly speaking is a 16th edition definition

Guinness

 

[Andy™]

"Phase" strictly speaking is a 16th edition definition

Guinness

so we now have '3 line' instead of '3 phase'?!

its all gone mad!

 

[SPECIAL LOCATION]

[quote name='Andy

 

[louisIV]

Thanks everyone. It's nice to know that it wasn't a totally stupid question, if the 17th Ed. has changed the definitions.

Thanks for pointing out Part 2 Special Location. I bought a copy of BS7671, but am guilty of not having looked at it much yet. This will change a lot over the coming weeks as we're just being introduced to cable selection/circuit design/current carrying capacities.

I'm at a point where I think I'm doing well, but I'm acutely aware of how much more I've got to learn! Sometimes I feel chuffed that I'm absorbing all this new stuff. Other days I feel very daunted ...

 

[revjames]

Give me Red Yellow and Blue Phase any time. L1 L2 and L3 wots that all about?

 

[louisIV]

The only definition of "Phase Conductor" says..See Line conductor.. ??????????

(pg 27)

Progress

Yes - I saw that. Phase makes more sense to me personally, as it's so closely bound up with the generating proceedure and real phase offsets etc. I am familair with that through my previous life as a recording engineer.

 

[SPECIAL LOCATION]

Give me Red Yellow and Blue Phase any time. L1 L2 and L3 wots that all about?

You old stick-in-the-mud you!!!

]

 

[philbas]

If you light up when you touch it, then its liveBlushing

 

[louisIV]

If you light up when you touch it, then its liveBlushing

I've found the 'Thanks' buttons on the forum. Is there a 'No Thanks' button I can press?

 

[batty]

I've found the 'Thanks' buttons on the forum. Is there a 'No Thanks' button I can press?

Wet Fish That usually works.

 

[revjames]

You old stick-in-the-mud you!!! ]

Red to red, yellow to yellow and blue to bits.........

 

[a1]

I've found the 'Thanks' buttons on the forum. Is there a 'No Thanks' button I can press?

Yes Mate, we do, as it goes...

 

[louisIV]

Yipppeeee! I just pressed the 'thanks' button for my 'no thanks' button. Applaud Smiley