Trying to install an American oven in Japan and I could use some help on the electrical side.

I have 200v single phase as well as 200v 3-phase in open-delta configuration, both in 60 hz

The oven specs say I need either 208v three phase or 240v.

The oven draws 4000w and the microwave 1600w.

I’m trying to decide what would be more appropriate.

A) hook it up to 3-phase 200v as-is. If I’m not mistaken appliances are permitted a 10% variance in either direction. 208v to 200v is less than 3%. Am I right or when using three phase does the 10% variance rule not apply?

B) Buy two of these: https://www.larsonelectronics.com/product/265090/1-phase-buck-boost-step-up-transformer-100v-primary-120v-secondary-31-25-amps-50-60hz

If I use these buck transformers, however, do I have to worry about this: “buck transformers do NOT generate even legs of voltage on the secondary side.” I’m no expert but this seems more important for electronics than it would for heating elements, although I might be wrong.

Any and all help/advice is sincerely appreciated.



Edit: So, I just brought my multimeter outside and took so pictures for extra clarification. This junction box has a puny 10amp breaker because it only for my well pump. So my plan would be to have a dedicated line run by an electrician solely for the oven. enter image description hereenter image description hereenter image description hereenter image description here

  • Can you post a photo of the nameplate of the oven please? Mar 3, 2020 at 4:53
  • 1
    Hi threephaseeel, I should have clarified. I intend to buy the oven once I have the electrical situation handled. Here is the oven: lg.com/us/support/products/documents/LWC3063-Spec-Sheet.pdf
    – Jayusa77
    Mar 3, 2020 at 5:02
  • Is your single phase 200V supply an actual 200V phase, or 200V split-phase? (I ask because most Japanese light electrics run at 100V, AIUI) Mar 3, 2020 at 5:09
  • To be honest, I have no idea. Perhaps this will help. It outlines the Japanese electrical grid: stamford-avk.com/sites/stamfordavk/files/AGN203_B.pdf
    – Jayusa77
    Mar 3, 2020 at 5:16
  • Could I take a picture of the power lines or something that could give you an answer to that question?
    – Jayusa77
    Mar 3, 2020 at 5:17

1 Answer 1


DO NOT USE 3-PHASE FOR THIS OVEN. You want a single/split-phase 100V/200V hookup. The 200V open delta is absolutely incapable of providing essential voltages the oven needs.

Simple enough hookup

Japan is straight-up North American style split phase, and range/ovens are resistive devices, so this thing will work. Voltage will be 17% less, amperage likewise... which means power will be 31% less. It'll work, it'll be a little slower to heat up.

You'll need to use the same breaker size the instructions specify. And make sure to connect it 4-wire, including a separate safety ground, and un-bond the neutral-ground strap on the range.

However, when in Rome, do like the Romans do

That said, I think a North American range in Japan is a mistake unless this is a standard/common appliance in Japanese homes. You are better off buying locally whatever Japanese tend to use.

The odd voltage and 69% performance is the least of the issues. To start with, if it's weird, the next homeowner won't want it. So you'll end up either scrapping it in place or taking it with you.

Japan is an island, and that means that beast will either need a ride in an airplane or containership. Airplane means creating 10 times its weight in CO2 and more than its retail value in jet fuel. It's an awful lot of cubic feet to use up in a valuable overseas container.

You're obviously a world traveler since you have a sentiment for American goods and are now in Japan. The idea of "taking it with you" is further corrupted by the fact that this unit will not work at all, anywhere else. Not even the Philippines. Only North America, US possessions, and ... Japan. Only.

Anywhere else, the answer would be "can't do it" or "hack it".

Ironically, the main reason ovens want 120V is so they can power oven lights, specifically so you can use readily available, indigenous oven lights. So jumpering the oven light to run on 230V in a 230V country, is exactly what the manufacturer does. There may be some 120V electronics, but that could be handled with a tiny transformer. Assuming the local power grid can provide 40A of single phase; many provide less of all 3 230V phases.

  • Harper, thank you for taking the time and effort to write such a detailed response. You made some very good points about “when in Rome” but I’ve lived here 8 years now and have no plans on living anywhere else. That said, I miss certain aspects of American life, a full sized stove being among them, so no matter the impracticality of installing an American stove, if it can be done I’m going to give it a shot. I already have the biggest oven they sell domestically and I can’t fit a normal size turkey in it. My biggest concern is safety. If I’m going to do this, it needs to be safe.
    – Jayusa77
    Mar 4, 2020 at 2:59
  • What are your thoughts on the buck transformers that covert 100v to 120v? That way my oven would operate at 100%, not 69%.
    – Jayusa77
    Mar 4, 2020 at 3:00
  • @Jayusa77 you could do that. I would boost by 40V the side the oven light is not on, so you can use common indigenous 100V bulbs, and then you only need one transformer. If you power it off the same breaker, the breaker will need to be upsized accordingly. Or you could power it off a dedicated breaker: 40V x 40A = 1600 VA, so provision 20A @ 100V or 10A @ 200V. Mar 6, 2020 at 0:00
  • Harper, thanks a lot. That’s exactly what I’ll do then. I really appreciate the response.
    – Jayusa77
    Mar 7, 2020 at 1:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.