# Powering both phases of home with 1 or 2 110V generators



## Nocturnal (Nov 4, 2012)

Hi,

at the moment I feed my home with a transfer switch that takes 220V from my generator and connects to both phases. Works great. 

I'm thinking of switching to an inverter generator but the price is giving me pause. Perhaps I should get 1 full sized or 2 smaller Lifan generators like the 5600iER. These only have 110V output.

Naturally I won't run dual phase equipment like the oven, AC and dryer. In that case can I connect the hot side of the large generator to both phases in my transfer switch? What if I have two smaller generators, can I connect the neutral and ground together and one hot to each phase? Lifan sells generators that can 'sync' to each other if that makes a difference. What I like about having 2 smaller generators is that there's no worry about load balancing. Also I want to have a backup anyway so with two smaller ones I'll have that. Of course it's double the maintenance.

Anyway, just wondering if it'll work electrically.

Meanwhile we're still without power in CT. They make the power system here out of twine I think.

Thanks,

Sander


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## Jones (Nov 11, 2012)

*Do not do it*

Your gonna have the neutrals of both jennies common you will have non synched sines resulting in harmonics and heat. It will cause damge. 

Jones


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## Nocturnal (Nov 4, 2012)

Thanks for your reply. I asked Lifan customer support and they said it would be fine. Now I'm a bit concerned. Their 5600iER model only has 110V output but I need to power both phases in my house. 

How would I test this? I have a generator that puts out both 110 and 220. I normally use the 220 output, I can test with the 110. I mean I understand how to wire things but how would I detect that it's causing problems without waiting for things to blow up?

Thanks,

Sander


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## BostonDan (Nov 11, 2012)

I would first find out how the generators sync. A 220V circuit is made by two hots which are out of phase by 180 degrees. If the generators synchronize out of phase by 180 degrees, you should be fine. But if the generators synchronize in phase, there will be no voltage potential between the two hots, this is done to support high current devices on a single 120V circuit. 

In the case where the generators are synced to provide a high current 120V circuit, you may end up damaging your 220V devices if those devices also complete a 120V circuit across one of the hots and neutral.


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## Nocturnal (Nov 4, 2012)

Hi,

Naturally I do not intend to run 220V equipment this way. I listed the oven, AC and dryer in my original post but I guess I wasn't clear or used the wrong terminology.

Sander


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## Jones (Nov 11, 2012)

*Manufacturer knows more then me but...*

The sine is naturally present in the neutral. With* two generating* sources the more out of sync the sine is in the neutral the more heat and harmonics you get.

The current waveform can become quite complex, depending on the type of load and its interaction with other components of the system. And is described through Fourier analysis.
Problem is exacerbated by non-linear loads. Some non linear loads include common office equipment such as computers and printers, Fluorescent lighting, battery chargers. We all have some of this equipment in the house. 
Increased current in the system...... this is particularly the case for the third harmonic, which causes a sharp increase in the zero sequence current, and therefore *increases the current/heat in the neutral conductor*. This effect can require special consideration in the design of an electric system to serve non-linear loads

In addition to the increased line current, different pieces of electrical equipment can suffer effects from harmonics on the power system. 
Required oversized neutrals is often the case for some new installations.

Me , I would not do it.

Jones


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## Apple206 (Jan 28, 2015)

HI guys - thanks very much for posting this info.


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