This is a nice, reasonably well-built isolation transformer - yes, isolation from mains ground in SPECIAL mode for those of you wanting tyo isolate devices under test, etc. The front display is a very nice feature. My unit is silent/near silent. For the price, I think this is hard to beat.Why four stars? Because shipping such a device without a manual is lame, but -even worse- there doesn’t even appear to be any available manual anywhere. I reached out to the company and all they have is a spec sheet, which is no substitute for a user manual.Why does this matter? There is no description of the soft start circuit and how it works on the unit. There is no description of the miniature circuit breaker in the power switch or how the over-voltage/under-voltage protection works (based on a bit of digging in YouTube, I would not trust this protection as it appears to trigger too late in both directions, but that’s not why you are buying this unit anyway, so no points off there). Most befuddling, the lack of a guide means there is no description of how the floating AC works (i.e., how you use it to disconnect from your mains ground). Digging around a bit you can find some answers, but this should really ship with a proper manual and some safety suggestions.OK - you must take full safety and training responsibility, but here are some suggestions. Safety liability is yours alone.Safety note 1 - there’s confusion, or at least a lack of clarity for me, in some of the reviews about the Standard/Special switch. Switching to SPECIAL gives you floating AC/isolated from mains ground. However, you should not trust me or anyone else - please get out your multimeter and do AC voltage/continuity tests yourself to confirm (my results below). You want to be sure, and if you start reading about isolation transformer tests online, you will find all kinds of user comments where equipment that is supposed to be a transformer doesn’t actually properly isolate the device under test or even has wiring mistakes. Confirm for your safety. If these doing these tests makes you uncomfortable - or they are too hard to figure out - save your money (and maybe life) until you have some more education.Safety Note 2 - There’s at least one suggestion that this is being used to isolate someone’s oscilloscope from ground. Maybe that was just another lack of clarity, but DO NOT ISOLATE YOUR OSCILLOSCOPE FROM GROUND. You CAN use this isolation transformer to ISOLATE THE DEVICE UNDER TEST FROM GROUND - that is the correct procedure. Do a little Googling to confirm this for yourself.Opening Unit. There are four screws on each side to open the unit - easy. Inside it is clean and well-organized as other’s picture show. Relative to the rear receptacles, in my unit yellow with green stripe is ground, blue is neutral, green is hot. Obviously not US standard. The neutral and ground are bonded and you can switch to SPECIAL to float the ground.Tests:STANDARD MODEHot to Neutral - 125V (my house runs a bit hot) - Continuity YesHot to Ground - 125V - Continuity YesNeutral to Ground - OV - Continuity YesSPECIAL MODEHot to Neutral - 125V - Continuity YesHot to Ground - 16.5V - Continuity NoNeutral to Ground - 6V - Continuity NoAs stated above, this shows that SPECIAL is isolated from ground. The reason that you get some low voltage for Hot to Ground and Neutral to Ground is due to parasitic capacitance. The Continuity Tests further show that, as expected, Hot and Neutral are both disconnected from ground.So, yes, it’s a real isolation transformer that is missing a manual, but otherwise quite nice so far. Hope this helps - please test yours and familiarize yourself with testing safety.

This hardware lacks a soft start feature. A 2000-watt unit. Otherwise, no other issues or problems were encountered. The outlet receptacle is compatible with global standards and accepts American standard plugs. A soft start mechanism will likely be necessary to prevent circuit breaker tripping. At 75% load, the unit operates quietly, exhibiting no objectionable humming.I have inspect it by removing cover and it looks built well.Outlet receptacle will have to be changed if you going to use this unit up to 70-80% of advertising power.

No documentation with the unit, sad. Put together rather well. Solder connections good. Nothing loose. Wiring in good order. Nice display feature. The switch on the back (Standard--Mode Switching--Special) functions as a isolation switch to earth ground. It grounds the receptacles to earth ground in the Standard mode When in the Special mode there is no feedback to the primary transformer or earth ground. The output in the Special mode is truly isolated! Tested this unit with a real "Hot Chassis" radio and worked as described.

item as described. have not had a chance to use yet.

Got my second one yesterday and it got bounced around in shipping from Texas to RI enough to dent outwards the sides from the core flexing on the mounting bolt as well as kink the base along one side bend lip. Should be shipped upright. The ground connects to the hot output terminal not ideal when the rear switch is on. The 120v socket is tight on the ground plug post it helps to taper the tip to insert easier, sockets look weird but work with USA plugs. Running 13+ amps will make power cords get hot even with heavy gauge cord. Work great to isolate a large boat from a ground fault.

Placing the standard - special selector switch in the special position eliminated most of the mains ground noise I was getting while measuring Also, reading other reviews someone was critical of the non-US recepticals on the unit. I wanted to mention that the receptacles are “universal.” There is a small plastic guard inside the receptacle. If you lift it with a small screwdriver (power off of course) it will accept a standard US plug.So, don’t hesitate. The unit works well and is a great isolation transformer for a reasonable price!

Not sure but I don't see a way to plug in a three-prong us adapter into the unit I received. It looks like it's made for other countries but not the US. Show me on there where I can put a three prong US plug? I don't think they sent me the right unit. Disappointing. Not exactly feeling with the sense of safety, which is what I bought the unit for in the first place. I have no place for a Us grounded plug. And so how would I use the ground lift switch?I sent it back. Was going to buy another one on prime and see if maybe it was as pictured in the ad this time. What's the deal? I don't know how to contact the company. Frustrating.

That is what I like from a product.

The outlets that others have had trouble with are odd but will take a standard 3 prong plug if you insert it just right. The trick is not to insert the plug straight in. If you do that a little plastic shield will get in the way and you can't get the plug in. To insert the plug you need to angle the plug upwards so that the ground does not go in at first. Use the two spade prongs to push the plastic shield up towards the ground pin. Then rock the plug forwards inserting the ground pin.