3-phase vs. 2-phase and UPB (Hai Omnipro2)

[DrizztSA]

Gents,

I have been perusing this site and have found it jam packed with a lot of information from a lot of experienced people.

So I have a question that may be rudimentary to most of you.

I am planning to purchase a Hai OmniproII system (or similar) and heard that UPB does nit work on 3-phase systems withput using a 3-phase coupler etc etc etc.

My first question is:

How do I tell if my house is wired as 2-phase or 3-phase. I know that I have both 110v and 220v outlets but how do I tell.

 

[Sandpiper]

Gents,

I have been perusing this site and have found it jam packed with a lot of information from a lot of experienced people.

So I have a question that may be rudimentary to most of you.

I am planning to purchase a Hai OmniproII system (or similar) and heard that UPB does nit work on 3-phase systems withput using a 3-phase coupler etc etc etc.

My first question is:

How do I tell if my house is wired as 2-phase or 3-phase. I know that I have both 110v and 220v outlets but how do I tell.

99.9% of residential homes are single phase. Some call this 2-phase since there are 2 120V hot legs, but it is actually single phase with a center tap.

You can tell for sure by looking inside your electrical distribution panel. However, I dont recommend you pull the cover with it energized. Unless your house if over 10,000 square feet, trust me, it is single phase.

3-phase systems are commonly used in commercial and industrial facilities.

 

[DrizztSA]

Sandpiper,

Thanks for posting.

You mention I can tell for sure by looking inside my electrical distribution panel. Can you elaborate.
In my house I can usually find two electrical outlets side by side 1 is 110V and the other is 220V.

In my electrical panel there seems to be 3 large wires hooked up. Again I have no clue what I'm looking at.....

 

[123]

...
In my electrical panel there seems to be 3 large wires hooked up. Again I have no clue what I'm looking at.....

Two black wires and a white one? 240V across the black wires and 120V across any black wire and the white one.

 

[Sandpiper]

Sandpiper,

Thanks for posting.

You mention I can tell for sure by looking inside my electrical distribution panel. Can you elaborate.
In my house I can usually find two electrical outlets side by side 1 is 110V and the other is 220V.

In my electrical panel there seems to be 3 large wires hooked up. Again I have no clue what I'm looking at.....

For 120/240 single phase, you will have 3 large wires terminated in the panelboard...two of them will terminate on the main breaker (which will have two terminals). The other wire is usually bare and will terminate onto a ground bus bar in the panel.
For a three phase panel, you will have 4 incoming wires. Three will terminate onto the top of the main breaker which will have 3 terminals. The other wire, will terminate onto the ground bus bar.

Also, if you really had three phase service, you would get only 208 volts phase-to-phase voltage, versus the 240 volts normally seen in residential service.

Again, please do not remove the panelboard cover to check. I'm quite positive you have single phase service.

 

[DrizztSA]

Thanks to all who have replied.

On the outside (Actually Inside my Fence wall not on the street) of my house there is one Large Electrical Panel which receives the electric cable coming in from the Electric Company.

My house also consists of 3 floors each floor with it's own panel.
I can see 3 Large Wires (Red, Yellow and Blue) hooked into the bottom of one of the panels as it is open.
May be I can take a picture of it, I'll do that today.

 

[DrizztSA]

Ok.

I have a little bit more information

The Main Electrical Panel which gets Electricity from the Electric Company is
GE Industrial Circuit Breaker
TJD434300WL
300 AMP Max 415VAC 3 POLE

From here it feeds 3 different Electrical Panels inside the house each are described as follows.
240/415 Volt 3Ph
4 Wire
100AMP Max 50/60 Hz
Type LA 3Ph 24 Way
R Y B wires

 

[Sandpiper]

Ok.

I have a little bit more information

The Main Electrical Panel which gets Electricity from the Electric Company is
GE Industrial Circuit Breaker
TJD434300WL
300 AMP Max 415VAC 3 POLE

From here it feeds 3 different Electrical Panels inside the house each are described as follows.
240/415 Volt 3Ph
4 Wire
100AMP Max 50/60 Hz
Type LA 3Ph 24 Way
R Y B wires

Wow! I am shocked. It does appear you have 3 phase. However, it is possible that your house was wired with 3 phase panels but only supplied with single phase, but I don't know why someone would do that. Here is how to tell 100% for sure. You will need an AC voltmeter.

1. At a 120 volt circuit (standard outlet) measure the voltage. I would expect between 110 and 120 volts. 115 would be typical.
2. Now at a 240 volt receptacle, such as for a electric dryer, range, or hot water heater, again measure the voltage.

Now if you have 3 phase, this voltage will be 1.73 times the voltage at the standard 120 volt outlet. 198 volts would be typical.
If you have single phase, this voltage will 2.0 times the voltage at the 120 volt outlet. 230 volts would be typical.