I have a Duromax "Beast" power generator that I've been using to run my home during power outages due to storms, etc. From the start, I decided to do things right and had an electrician install an input outlet with a manual transfer switch onto an exterior breaker panel which feeds the house; a high-quality cable runs power from the generator into the panel.

We had a recent hurricane and once I figured things out, the generator ran things near-flawlessly. However, in researching generators, I read about sine waves and how generators supply "dirty" power, so I was worried about using any sensitive electronics -- TVs, computers, cell phone chargers, cable modem, etc: we unplugged every single one of those things and didn't use them.

I have a relative who is an electrician, and he argues that if I have decent surge protectors on those outlets, then all of those sensitive electronics should be absolutely fine, and this is echoed somewhat on a couple of sites where I've been researching this issue. However, someone else argued what I was thinking: surge protectors guard against spikes in power, not sudden drops or brief spans of low power...and those could possibly damage sensitive electronics as well.

Which of us is correct? Am I being overly worried and good surge protectors are truly all I need? Or is that honestly just a makeshift measure and there are better solutions? Which one is likely to be the most effective...and economical?

Thank you in advance for all of your advice!

  • 1
    I did a bit of research on this subject and I think there's a lot of snake oil salesman out there. As I've often said before and hate to say it again: "it depends". Not all generators are created equal, so it really depends upon your specific generator. "Inverter" generators seem to be the best. But you can also use a UPS to protect sensitive electronics, just be sure it's compatible with your generator and it puts out a true sine wave, not a modified sine wave. ...just to share, your mileage may vary, but I've run computers on a crappy old noisy Generac years ago with no problems. Commented Feb 14, 2021 at 16:46
  • We had 3 generators connected to three hydro turbines that ran tv’s, computers, phone system etc etc and it was the cleanest power available. A BBC sound tech was actually impressed as it was the cleanest he had ever used. So use a quality generator.
    – Solar Mike
    Commented Feb 14, 2021 at 16:54
  • With first generator(small), I think one of the tips in manual said to plug in a incandescent light(desk lamp) before using electronics, was to clean the power a bit. Would not trust this unless a professional also suggested it.
    – crip659
    Commented Feb 14, 2021 at 17:33
  • What's your core concern? Having the electronics take permanent damage? Or losing some of your work and having to reboot if there's a brownout? Commented Feb 14, 2021 at 18:06
  • surge protectors won't do anything to condition the power, but aren't a bad idea in general. Old resistive and inductive devices won't really care (think lamps, irons, motors, toasters, etc). New DC-powered devices like computers, phone chargers, etc won't care either. So what would care? Certain things from the 70s-90s that use linear power in naïve ways, think CRT TVs, older microwaves, some fluorescent fixtures, and loud buzzers. The only common recent devices you'd likely notice issues are some style of (cheaper mainly) dimmable LEDs not dimming correctly.
    – dandavis
    Commented Feb 15, 2021 at 16:43

1 Answer 1


This is a half answer, based on some parallel knowledge not directly related to small home generators, so bear with me…

The only generators I get near are those on movie sets, which are gigantic by comparison - see Aggreko for an idea of the sizes I'm talking about. These, of course, are smooth as silk so require considerably less external mitigation.

Basically, you need several levels of protection if these are not already built-in to your generator.

Power limiting - ie surge protection.
Brownout - power slump - protection.
Grounding protection & isolation.

Delicate electronics don't like any of those. A general purpose mains surge protector will be the least likely to come into play in this, but shouldn't be skipped; they're dirt cheap. The other two could be more insidious.
A UPS (uninterruptible power supply) is the standard method of protecting computers & other delicate electronics from brownout or even total power-loss. These are an entire topic to themselves, but start fairly cheap & run to 'ouch' prices.
Grounding protection/isolation may be built into these - pay more, get more. Essentially, grounding protection is built on the 'in-house' side of a 1:1 coil-wound transformer. These seemingly odd little boxes - 120v in, 120v out, (or 240v i/o as appropriate) seem to do nothing; but they isolate one circuit from another. You then correctly ground the 'in-house' circuit to achieve total isolation from the external power supply.

  • Only get brown out if you fail to calculate your loads properly.
    – Solar Mike
    Commented Feb 14, 2021 at 17:08
  • You only get any of them if something is not working to plan, hence the term 'protection'. I'm sure no-one actually intends that their gear only works to spec 80% of the time.
    – Tetsujin
    Commented Feb 14, 2021 at 17:10
  • Only need one person to plug one thing into the wrong socket like a 2000W vacuum cleaner into the ups for the computer... seen it done and laughs for all.
    – Solar Mike
    Commented Feb 14, 2021 at 17:15
  • I'm not really sure what message you're trying to get across here… that mitigation is pointless, or that stupid can always happen whatever you try to do. The two seem at odds with each other.
    – Tetsujin
    Commented Feb 14, 2021 at 17:17
  • i'm used to structures where adding another 3 or 4 18Kw lights is going to make no difference - but someone has to keep a tally of total load. The big rigs will tally for you these days. At consumer-level, the general rule would probably be "don't plug the electric fan heater in the UPS (more than once;)"
    – Tetsujin
    Commented Feb 14, 2021 at 17:20

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.