changing electrical something through cable rearrangment

[Daniel Madsen]

I can't remember what it does specifically, but I remember reading that you can change in what fashion your hot and ground lines are connected to your power plant ( in other words other than red to red, blue to blue, green to green.) By switching them (and I am not sure how) you can get not another type of service (i.e. single, triple phase) but higher voltage. Try to help me out here.

 

 

Dan

Edited January 30, 2007 by Danielle Frankinshten

[Hal Smith]

I can't remember what it does specifically, but I remember reading that you can change in what fashion your hot and ground lines are connected to your power plant ( in other words other than red to red, blue to blue, green to green.) By switching them (and I am not sure how) you can get not another type of service (i.e. single, triple phase) but higher voltage. Try to help me out here.

Dan

If the plant is single phase, and assuming standard color codes: There is 120 volts between Black (Line 1) and White (Neutral), 120 Volts between Red (Line 2) and White, and 240 volts between Black and Red. Green is always supposed to be for metallic grounds and not used to carry circuit power.

 

There are two "flavors" of 3-phase power, Delta and Wye (referring to how the transformers feeding the 3-phase service are wired). Wye is the most common for studios, generators, etc. Delta is more often found on permanent building wiring, etc.

 

208 volt Wye has 208 volts between each phase leg (Black, Red, Blue) and 120 volts from each leg to Neutral (White) .

 

240 volt Delta has 240 volts between each leg, 120 volts from the Black and Blue legs to neutral and 277 volts from the Red leg to neutral (the "wild" leg) .

 

Watch out around Delta, most electricians will color code the wild leg Red and make it the middle feeder on terminal blocks, 3-phase breakers, etc. But its always best to measure any three phase power between all three leg to leg combinations and each leg to neutral before hooking anything up. I've had a power company tell me that a facility was fed with Wye, only to find out that it was really Delta, the wild leg had a rather fatal effect on a newly installed surge suppressor, the suppressor was ordered for Wye since that's what the power company said was there.

[Steve Zimmerman]

on a similar subject: Are there any recommended books on this subject of power distribution? I don't remember any of this in "The Lighting Technician's Handbook". :o I was disappointed when I signed up for a class on generator operation from the regional IATSE union, but they must have cancelled the meeting because they never called me back.

Edited January 30, 2007 by Steve Zimmerman

[Hal Smith]

on a similar subject: Are there any recommended books on this subject of power distribution?

Good question: I'm not certain if there is a one-stop book on power distribution but if there is, it'll be in a book aimed towards working commercial and industrial electricians. I've got an old "Lineman's Manual" that has a lot of the right information in it, you might look around on Amazon for something like it.

[Paul Bruening]

Around here, they call 3 phase, "faktra waard" because 3 phase is a great system for industrial motors. My Cummins is Wye wired. In my early days I blew a whole bunch of lamps on a 3 phase system. At $60.00 a lamp I learned my lesson.