UTS6H and breaker box leg feed questions

[Anonymous user]

I was curious on the designed behavior with the UTS6H.  I understand the 110v/120v of the UTS6H vs 220v/240v nature of the UTS6(BI) and UTS10(BI) for the generator feed. I am considering the UTS6H with a Honda EU2000i but wanted to verify a few things.

With load balancing and wiring a 240v utility fed house at the breaker box without a transfer switch, the phase difference is how you end up with the 240v from the dual 120v utility feeds.  If you have the UTS6H and you pick (for argument sake) two circuits on the left half and four on the right half of the house breaker box, I do not believe you need to load balance the two halves as the UTS6H is only 120V driven from the generator.  Is wattage capacity your only/main concern at that point regarding proper setup? 

Are there issues with having circuits on different phases of the house feed and switching over to the single phase generator feed and back again or is there enough down time between sources that everything is fine?  Or, is there enough tolerance in household electronics to not care if the UTS causes the feed(s) to be out of sync for one half cycle if the source toggle is almost instantaneous?

Also is there a risk of what I would inappropriately call phase-lock between the left half and right half or does the UTS6H isolate the halves of your breaker box when running on utility power and merge them (the six circuits you wired into the UTS6h) when running on 120v generator?

One more question for tonight, should you set the maximum wattage for the generator in the UTS6H to the 2000 watt peak the EU2000i can handle for up to 30 minutes, set it down to 1600 watts that it can do continuous, or somewhere in the middle?

I imagine this is all me being overly cautious and it is perfectly safe to use the UTS6H on both halves of a two phase residential breaker box, but I wanted to verify phase-lock and circuit count wise being unbalanced were not issues.

Thank you

[BillP · Accepted solution]

Hi squeegee,

When the UTS6H senses a loss in utility power, it will disconnect itself from the Main Distribution panel by closing a single relay for each circuit. The panel will remain inoperable for a minimum of 5 seconds, to ensure these relays latch open properly. This is referred to as CPLD or Circuit Protection Load Disconnect. By opening these relays, the UTS6H is capable of isolating itself from the Mains, as to not back-feed onto the utility source. Once isolated, the UTS6H is now capable of passing power directly from the attached generator to the desired loads without issue. Although the generator is sized for a maximum of 2000w peak, it may be best to reference the 1600-1800w as the generators maximum and allow the UTS panel to disconnect loads as it deems necessary through Adaptive Load Management. An option however which is strongly recommended, would be to add an additional UPS to the UPS inlet. This will provide you the additional watt capacity of the UPS during extended outages, in addition to your single phase generator.

I hope this helps.

[Anonymous user]

Thank you SecretSquirrel.

From the sounds of it, consider my home's breaker box as it is, and consider the UTS6H as it's own complete setup.  The isolation of the circuits with the relays take the balance out of concern with the UTS6H being single sided with 120v.

We shall see how fast the wife lets me invest in this, she has a hard time believing we have any need due to only loosing power once in over ten years for more than five minutes, and only two blips for a few seconds.