UTS10BI - Be Aware of its design limitations before purchase

[BillP]

I just want to get the word out on forums, etc. regarding the UTS10BI Universal Transfer Switch (the APC reps don't seem to know too much about these units) so that other potential buyers do not go thru what I went thru with this unit.

In general, IMHO, APC overlooked a key item when designing this unit. In short, the UTS10BI has 6 120V circuits, and 2 120V circuits that must be be used together as a 240V circuit. In general, this seems fine. Where the problem resides is that this 240V circuit is what powers the UTS, so it MUST BE CONNECTED to something else the UTS will not receive utility power to operate.

The major design flaw that I found was that the circuits are all rated at 20amps, including the 240V circuit. If you live in a somewhat modern house, before purchasing - go check out your breaker panel and see if you can find a 240V circuit that is 20amps - odds are you won't.

So my electrician and I learned this the hard way. We hardwired my 240V circuit to one in my breaker box per the installation instructions, and as soon as that circuit turned on (be it the 30amp dryer, 40 amp AC, etc) it immediately blew the 20amp fuse internal on the UTS. And its not as simple as throwing a breaker to fix - the panel must be removed from the UTS10BI, and the faulty fuse removed.

The only way I'll ever get the UTS10BI to work is to have my electrician install in my breaker box a 240V 20AMP circuit that is solely dedicated to powering this UTS10BI.

IMHO, APC messed this up. Be warned.

[BillP]

hi

i definitely want to clear up a couple things here for users that come across this thread and also to assist you as well Joe since it seems like you have gone through a less than desirable experience with this product.

to begin, i would certainly be interested in any other further info (via private message or posting it here) on an APC case or incident number or correspondance that I can review in regards to your dealings with APC tech support. i can assure you the people that post on this forum are very well versed in the product.

also, i am not sure if it was a typo or something but the UTS10BI has (8) 120v circuits and not (6). Then there is the remaining 240v circuit using numbers 9 and 10.

the important thing to understand is that the UTS10BI was designed to work optimally with PORTABLE generators that are rated 240V/30A or less. portable generators are not normally used to back up dryers (30amp) or central air (40amp) because they would instantly overload the generator, or leave no capacity for anything else in the house to operate. as far as i know, the fact that the UTS10BI accepts input from generator rated 240V/30A, or optionally using a hardwire kit, 240V/50A. is clearly stated on the box for the unit. (The hardwire option (UTSHW) to allow generators rated upto 240V, 50A to be wired to the UTS, but the 20A limitation on any individual circuit still applies.) What is also clearly stated in the box is that the OUTPUTs (120V or 240V) are rated for upto 20A max. The 120V outputs are rated for 15A as factory default, (but can be upgraded to 20A using the included spare fuses).The 240V output is rated for 20A by factory default.

If a particular household doesn't have 240V/20A circuits available, it is relatively easy to add a pair of ganged breakers to provide this (if there are open breaker slots), or to rewire 2 existing (unused) 120V circuits to become 240V/20A circuits. It is true however that if the circuit is used only to power the UTS, and not any real loads, then this is not the most efficient use of the breaker panel or the UTS.

we are interested to know what size generator you are using and if you are using the UTSHW generator hardwiring kit. depending on what we find out, down the line, there could be possibility of having a UTS wither greater capacity than 20A for the circuits.

lastly, you do make a good point - some users may want to back up larger loads using a fixed standby generator system, and would benefit from the advanced load management features of the UTS.

EDIT: ALSO - Another note is that it is clearly against the electrical code to connect a 30A branch circuit to a transfer switch circuit rated only for 20A. The electrician/installer is responsible for ensuring this doesn't happen which is why APC only recommends installation by qualified personnel.

[mitchh_apc]

I would be all over a version of the UTS10BI with a 30a 240v circuit, or one that was limited to 20A on backup but could do 30A (or more) on mains. I have a well with a 2500 gal holding tank and so there are two pumps involved, each with a 20A 240V circuit at the well head but the whole shebang is fed over a long run of cable via a 30A 240V circuit from the subpanel where the transfer switch would go. I would be happy to go flip breakers at the well and run only the well or only the tank pump when on emergency power, but in "normal" operation I need the 30A headroom for both at once. (This is somewhat like the poster on another thread with his furnace on the other end of a remote 50A subpanel, only closer to what you've already got 🙂 )

So count me as a +1 for greater capacity on the 240V circuit, and maybe just maybe would you have any news for us?

Message was edited by: mitchh

[Anonymous user]

I disagree with the original poster on a variety of points:

(1) - The UTS10BI has (8) dedicated 120V circuits, not (6).

(2) - The 20A circuit it meant for use to power a well pump or furnace, not a dryer, A/C unit, or HWH.  More amperage on the 240V circuit would be advantageous, but then would cost more since APC couldn't use the same hardware that they are using in common with the other 120V 20A circuits.

(3) - You don't need to install a separate 120V breaker just to power the UTS (although this wouldn't cost much).  You just need to connect the "IN" wires for circuits 9 & 10 along with an existing function, but leave the existing function connected.  The "OUT" wires for circuits 9 & 10 aren't connected to anything, much in the same way as if you installed a separate breaker anyway.

[BillP · Accepted solution]

What a wonder it is that the Internet saves everything! I made this post way back in 2009 after installation when I was finishing my basement. After getting this installed and installing separate 20A breakers to #9 and 10, everything has worked fine for the past 6 years. However, luckily I have not needed to use it - weather has been nice and no power outages. But some day I will need to use this as designed. Which means that after 6 years, I have yet to connect a generator to the UTS10BI. I have not yet even purchased one.

I made the original post above but failed to check back on it for responses. I'll get this out of the way early - I really like the UTS10BI but the entire system design/package/installation was never marketed clearly to myself or my electrician. The details per Angela above are printed on the box and the manual, but unfortunately the product is not marketed or sold as a complete solution. To be fair, I did get the idea to buy an APC UTS from the Honda website - where the UTS6 IS marketed as a complete solution, but I deviated from the UTS6 because I wanted the additional circuits, and that is where myself and my electrician ran into confusion.

I also purchased the UTSHW hardware kit and my electrician installed on the outside of my house. Now my question is: what type of generator would be best?

My intentions all along were to purchase a smaller 2000W genset like the Honda EU2000i or comparable Yamaha. The APC product with load balancing is ideal - my lifestyle supports a smaller, portable generator for outdoor family activities and the UTS10BI can also help it support my home in case of power outage. I sdon't want or need a larger capacity generator.

The comments from Angela all make sense, I understand the 20A limitation and that is all that is needed in my application.

But per above, the comment of  "the hardwire option (UTSHW) to allow generators rated ***upto 240V***, 50A to be wired to the UTS" I am not so sure about. Reading other posts here on the APC site regarding the UST10BI seem to indicate that ***ONLY*** a 240V generator (not a 120V generator) can be connected to the UTS as it needs 240V to power the unit?

I read the threads about the possibility of using an 120V generator on one input AND a UPS for source 2, but my UTS is not installed in a mechanical room or an electrical closet, rather, it's on a finished wall in my basement (it looks nice, BTW) and a UPS would not be cosmetically ideal. Furthermore, I never intended to purchase a UPS nor need instant failover - I just wanted a UTS that would provide backflow protection to the grid and auto load balancing so I could use a small generator.

Unfortunately, the 240V generators from Honda and Yamaha, while portable, are not my preferred solution.

Please comment on my questions above. I do really like this UTS, and if need be, I'll sell it on eBay and replace with the UTS6.

Many thanks!

Marc