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# Electrical Wiring FAQ (Part 2 of 2)Section - What is 3 phase power? Should I use it? Can I get it in my house?

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Top Document: Electrical Wiring FAQ (Part 2 of 2)
Previous Document: Noisy fluorescent fixtures, what do I do?
Next Document: Is it better to run motors at 110 or 220?
See reader questions & answers on this topic! - Help others by sharing your knowledge
```
Three phase power has three "hot" wires, 120 degrees out of
phase with each other.  These are usually used for large motors
because it is more "efficient", provides a bit more starting torque,
and because the motors are simpler and hence cheaper.

You're most likely to encounter a 3 phase circuit that shows
110 volts between any hot and ground, and 208 volts between
any two hots.  The latter shows the difference between a normal
220V/110V common neutral circuit, which is 240 volts between the
two hots.  There are 3 phase circuits with different voltages.

Bringing in a 3 phase feed to your house is usually
ridiculously expensive, or impossible.  If the equipment you
want to run has a standard motor mount, it is *MUCH* cheaper to
buy a new 110V or 220V motor for it.  In some cases it is
possible to run 3 phase equipment on ordinary power if you have
a "capacitor start" unit, or use a larger motor as a
(auto-)generator.  These are tricky, but are a good solution if
the motor is non-standard size, or too expensive or too big to
replace.  The Taunton Press book ``The Small Shop'' has an
article on how to do this if you must.

Note that you lose any possible electrical efficiency by using
such a converter.  The laws of thermodynamics guarantee that.

```

## User Contributions:

Dev
Dec 21, 2011 @ 12:00 am
In a fire protection circuit, circuts are shown witha no example 6,8,4etc. what it mean?these circuits are connected between smode detector,junction box etc
kevin
Dec 24, 2011 @ 12:12 pm
My daughter dropped a small necklace behind her dresser. The necklace crossed a plug terminal and shorted the receptacle.
I bought a new receptacle and installed the same. I still have no power I suspect there could be a bigger problem,this is aluminum wiring.
I've killed the breaker and call an electrician but am curious as to what happened.P.s. there is a dimmer switch on the same circuit.
dennis
Feb 24, 2012 @ 11:11 am
Regarding new construction wiring and running 12/2 and 14/3 wire in the same box.

I have multiple switches to lights. Ran 12/2 and 14/3 into switch box and inspector wrote correction needed.

What should I have done instead?

thank you
dennis
Robert
Nov 26, 2012 @ 9:21 pm
Does a grounding electrode facilitate the operation of a OCPD, to clear a ground fault ?
@dennis
Mar 18, 2013 @ 10:10 am
Assuming you are installing two switches in a two switch box, you probably should have used 14/2 and 14/3 instead of replacing 14/2 with 12/2. If you are only installing one switch in a one switch box, you should only have one cable in the box.
P k
Jan 26, 2014 @ 10:10 am
I prefer to use nothing smaller than12 awg /the smallest sized wire on a circuit determines the allowable ampacity
Ex: 15 amp-14awg. 12awg-20amp only rule for thumb other factors such as continuous load,heating and others if you do not know the safe NEC rules then please call a qualified journeyman Electrician better be safe

Top Document: Electrical Wiring FAQ (Part 2 of 2)
Previous Document: Noisy fluorescent fixtures, what do I do?
Next Document: Is it better to run motors at 110 or 220?

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Last Update March 27 2014 @ 02:11 PM