# Difference between Phase and Line

#### electronicsLearner77

Jul 2, 2015
234
When I am reading 3 phase systems, i very frequently listen the terms phase and line. Both of them almost look similar but yes there are differences. What is the exact definition and are there any shortcuts which can help me to easily remember a phase and a line?

#### Minder

Apr 24, 2015
3,324
Depends on the context they are used in, you would need to quote an example.
Line often refers to one phase against the neutral, as in 'Line (live) and Neutral'.
M..

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
12,774
In a 3 phase system the three phases are often labeled L1, L2, L3, or R, S, T or Ph1, PH2, PH3 ...

#### electronicsLearner77

Jul 2, 2015
234
Ok, in the Y windings, the line to line voltage is sqrt(3)*Phase voltage. And for Delta connections the
line current is sqrt(3) times the Phase current. So, basically when understanding the conversion formulae of voltage and currents in Y and Delta connections.

#### electronicsLearner77

Jul 2, 2015
234
Line often refers to one phase against the neutral, as in 'Line (live) and Neutral'.
M..
When you say line is live i assume a voltage is available in that line, why phase is not live, here also voltage will be available?

#### Minder

Apr 24, 2015
3,324
I suspect it is mainly a matter of semantics.
Phase to Neutral/Line to Neutral, used interchangeably!
M.

#### Kabelsalat

Jul 5, 2011
176
Assuming you refers to voltages: I don't know if the term is more vague in other places of the world, but here (Norway) there is a very distinctive difference between the terms:
Phase voltage : Voltage between neutral/ground to phase.
Line voltage : Voltage between phases.

#### Bluejets

Oct 5, 2014
5,995
Line can also refer to the input to a circuit breaker or piece of equipment whereas load is the output.
Just another comparison.
Line and phase, same thing.

When you say line is live i assume a voltage is available in that line, why phase is not live

Both phase and line are live with respect to neutral and ground.

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