voltage question - Electrician Talk - Professional Electrical Contractors Forum

Julius793 · 04-11-2012, 03:26 PM

i was wondering on a 120/208 3 phase system, phase to phase is 208v and phase to neutral is 120v why is this shouldnt phase to neutral be 104v? i know it is this way im just wondering why

Cletis · 04-11-2012, 03:55 PM

Quote:

Originally Posted by Julius793

i was wondering on a 120/208 3 phase system, phase to phase is 208v and phase to neutral is 120v why is this shouldnt phase to neutral be 104v? i know it is this way im just wondering why

here

Dnkldorf · 04-11-2012, 05:16 PM

Quote:

Originally Posted by Julius793

i was wondering on a 120/208 3 phase system, phase to phase is 208v and phase to neutral is 120v why is this shouldnt phase to neutral be 104v?

You forgot to add the 16V back into the equation.

Rookie mistake.

BBQ · 04-11-2012, 05:55 PM

Quote:

Originally Posted by Julius793

i was wondering on a 120/208 3 phase system, phase to phase is 208v and phase to neutral is 120v why is this shouldnt phase to neutral be 104v? i know it is this way im just wondering why

With 240 the two legs are exactly opposite each other, in other words 180 degrees apart from each other.

With 208 the phases are not 180 degrees apart they are each 120 degrees aprt from each other, that means you figure it differently.

As always with 3 phase 1.73 comes into it.

120 volts x 1.73 = 207.6 volts.

Julius793 · 04-11-2012, 08:38 PM

thanx guys

**frenchelectrican** · 04-12-2012, 01:19 AM

Julius793.,

Just let you know it is the same way as 480Y277 volts so let ya know that one as well.

Merci,
Marc