I'm considering a portable generator which provides 240V power to run both 240V and 120V items in the house during an outage, but it says the generator is single phase. Is this correct for what is needed?

Assume that there's an interlock for safety and that the bonded neutral problem is properly addressed. Also assume low THD to not damage sensitive items.

1 Answer 1


Residential power in the US is split-phase power. Some people mistakenly think this is the same as "two phase" power, but its not. We use single phase power of 240v that is split in the middle to also provide 120v circuits.

In commercial settings, three-phase power is a thing, but no one (that I'm aware of) uses true two-phase power so that is almost always a misunderstanding.

  • Thanks - I think I had some of that misunderstanding on that front so helpful to know. Does that mean this generator should be good for powering both 120V and 240V in the house (subject to having enough wattage of course)? The generator has a L14-30R receptacle. The model is A-iPower SUA6000ED and link to the manual is powerequipmentdirect.com/manuals/… in case helpful
    – g491
    Nov 12, 2021 at 19:09
  • 2
    Yes, that connector will provide the same 3-wire split phase power that your appliances expect. I have seen some small generators that only have 120v outlets, but all the 240v generators I have seen can also power 120v devices.
    – JPhi1618
    Nov 12, 2021 at 19:12
  • 4
    Here's a sassy but really good video on how US power works. youtube.com/watch?v=jMmUoZh3Hq4 Nov 12, 2021 at 19:49
  • 1
    @Harper-ReinstateMonica I appreciate that video having non-automatically-generated subtitles.
    – user
    Nov 13, 2021 at 1:58
  • 1
    @user I appreciate everything that Technology Connections does. Browse around, it’s a great channel. Oil lamp series was great.
    – JPhi1618
    Nov 13, 2021 at 2:00

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