1 Phase vs 2 Phase vs 3 Phase

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  #1  
Old 07-29-13, 10:51 AM
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1 Phase vs 2 Phase vs 3 Phase

I am trying to order power to my house. The problem is, there is no such thing as a "certified electrician" here, much less and type of "code" regulating wiring, power consumption, etc. So any comments regarding getting a certified electrician to help me is useless. I have to educate myself so I dont get ripped off.

I have a 1500 sq ft house. Besides lights, the only thing that uses power is the refrigerator, a washer/dryer, inline electric hot water heater, air conditioners (not central air), 2 TVs and some laptops.

In other homes very similar to this one, I have used less than 150kw per month. I am sure this will be about the same.

Here is my problem:

The power company can connect my house to the power grid using 1 phase, 2 phase, or 3 phase. Single phase only delivers 120v where 2 and 3 phase can deliver from 120v - 208v. I have nothing that requires more than 120v single phase in my home. The power company is refusing to connect my house to single phase because the wiring from their meter to my access panel is wired with 6 and 10 gauge wire.

They are trying to explain to me that since I only have 6 and 10 gauge they can only wire me with 3 phase power. This sounds like a crock to me. As from what I know, wire gauge has nothing to do with phase. If I'm wrong, please correct me.

They are telling me if I had 6 gauge and 4 gauge wire, then they could wire me with single phase. Again, this just doesn't make any sense to me. The difference in price between single phase and 3 phase will amount to several hundred dollars per years. (The power company charges a minimum per month whether the power is used or not. With 3 phase, they charge twice as much minimum over single phase).

Can anybody help explain this to me? Is there really any difference between the gauge of the wire and the phase?

There is one more thing, that I just dont understand. I have a choice of receiving 10kw or 5kw (you can decipher the meaning of what that is). They claim that if I elect to receive 5kw instead of 10kw, some things in my house wont work. Such as the dryer, hot water heater, etc. They also claim that the lights will not be as bright and will dim.

Thanks for your help in advance.
 
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  #2  
Old 07-29-13, 12:03 PM
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Without knowing what country you are in, it will be hard for anyone on this forum to make any suggestions at all; you didn't fill out your profile.

My first thought is the phase of your service panel (1 phase, 2 phase or 3 phase) must match your service panel. My second thought is that you'll want to be able to have up to 10KW.
 
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Old 07-29-13, 12:27 PM
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OP is in the Dominican Republic.............................

Yes...gauge makes a difference. A smaller wire can carry less current at a higher voltage (which I'm sure they are really talking about) and equals the same power as a larger wire carrying more current at a lower voltage. A piece of equipment that can operate on different voltages will use less current at a higher voltage, therefore the wires can be smaller. I'm not sure how the phase comes in as that is normally only an issue in industrial applications.

It seems like the best thing would be to upgrade the wire to your panel. The cost would be paid back in just a few months.

You have a very strange electrical system there. Nothing like what the US has for residential, thats for sure. Here, almost every home (except some old ones or small camp cabins and the like) are fed 240VAC single phase which is then split to 120VAC single phase for simple lights and outlets. The 240V supplies things like ovens, A/C, dryers, and water heaters. We don't rate our service by kilowatts either...we use amps. 100, 150, 200, etc.
 
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Old 07-29-13, 12:41 PM
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With a multi-phase system the load is split across the phases. With only a single phase the wires need to be larger to handle the load.
 
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Old 07-29-13, 12:42 PM
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Unless it is made especially for the Dominican Republic you won't find anything that runs on 2-phase. 2-phase for the most part was replaced by 3-phase 60-70 years ago. I'm a bit surprised they even offer 2-phase.
 
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Old 07-29-13, 07:13 PM
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OP is in the Dominican Republic.............................
Did I miss something? I was wondering how you determined what country the OP is in.
 
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Old 07-29-13, 07:16 PM
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SuperMod magic Joe....we have a few different accesses.
 
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Old 07-29-13, 07:58 PM
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I am wondering if what the OP describes as "two phase" is just our single phase.

Single phase = Two wires 120 volt only
Two phase = Three wires 208/240 between two hots, and 120 volts to neutral/ground
Three phase = Four wires 208/240 volts between three hots and either 120 between two hots (Delta) or all three hots (Wye)

If the above is true, I would suspect you would want "Two phase" and a 10KW (10,000 watts) transformer.
 
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Old 07-30-13, 08:17 AM
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High leg

On a delta connection one phase is referred to the "High" leg and runs around 200 volts phase to neutral.

A 3 phase system is more efficient and gives you a better balanced load
 
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Old 07-30-13, 10:21 AM
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The OP hasn't been back since his initial post. I am assuming this is an existing house, but that wasn't specified. I still say that one of the determing factors is the existing service panel.

Tolyn Ironhand

I am wondering if what the OP describes as "two phase" is just our single phase.

Single phase = Two wires 120 volt only
Exactly right, TI. The OP stated in his first post:

Single phase only delivers 120v where 2 and 3 phase can deliver from 120v - 208v.
So, Ken Harrington, is this an existing house and if so, what type service panel do you have? Is it 1 phase, 2 phase or 3 phase?
 
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