Generator and Power Surge Protector Won’t Play Together

[Dream Maker]

We have two Belkin surge protectors to protect our laptop and camera gear etc. from electrical spikes. We are having trouble getting our NextGen 3.5kW generator (it's under warranty) and the power surge protectors to work at the same time. The power surge protectors work fine when we charge from our diesel engine/alternator, shore power, or from the batteries. However, as soon as we turn the generator on with the surge protectors turned on, the GFCIs trip and cannot be reset until the generator has been turned off and a period of time elapses. The GFCIs do not trip when the generator turns on if the power surge protectors are turned off. We could plug into the 110 volt outlets without the surge protectors but we are concerned that we may damage our computer and other electronic gear if we do not have a surge protector.

The NextGen people say that power from a generator is not smooth like shore power and don’t have a solution for us. They said we should put an oscilloscope on to see what’s happening. As we are currently cruising in the Caribbean, that’s not so easy to do, nor do we understand what that will tell us.

We have had two surge protectors go bad on us and have replaced them. Not sure why. One may be due to age. The second was less than a year old. The GFCIs have all been replaced as we thought maybe they were the problem.

We don’t want to fry our electronic gear. Any ideas?

Thanks in advance for your ideas.

[Hud3]

I had that problem with a portable Honda generator that I hooked up to my house. In that case, the GFCI on the Honda tripped every time I turned it on. Turns out that the Honda had the Neutral and the Ground bonded together internally. With Honda's blessing, I removed the jumper, and all was well. Don't know if this applies to your situation, but you might want to check into it.

[colemj]

I think the NextGen generator should also bond the neutral and ground internally. I had this same problem with a different generator and found that replacing the GFI with a different brand (I forget which one) solved the problem. Mostly. It still trips now and then when the generator starts, but pushing the reset switch solves the problem. Maybe some GFI's are more sensitive than others?

Mark

[hellosailor]

What Hud says about gensets not having proper isolation is indeed common. Remember, a genset is often designed for portable use and "earth ground" is not an intrinsic part of that setup, unlike AC distribution systems.

Surge protectors go bad quite simply from two reasons: Cheap stuff--often counterfeit--or spikes. They are consumable parts, like tungsten light bulbs or fuses, and they are actually rated to withstand "this much zap this often" and then expected to fail and be replaced.

HPS10, Portable handheld oscilloscope, 10MS/s, model #HPS10 - All Spectrum Electronics
The Velleman solid-state "scope" at $135 s a surprisingly good tool, small enough for boat use, too. If you really need to go as far as buying one.

So it could be simply that your genset has such a dirty AC output, that it is chewing up the surge protectors. There are some more expensive types that use inert-gas filled spark gaps and such that might last longer, but the only way to really see what is going on would be an osciloscope on the genset output. Or--if you can find someone else with the same model, try to get their output scoped. Pretty much every marine electronics or land mobile radio repair service should have an ocilloscope, and if you can find any ham radio operators there's a good chance one of them might be able to provide a scope in exchange for a daysail or a cold drink and the challenge.

Otherwise...all you can do is try to buy a better surge protector (one rated for more "joules" of surge protection) or find specs on the generator output. The actual working component in a surge protector can be any of several types, typically they can be replaced for less than a buck apiece, you don't have to buy a whole power strip or surge box to do that.

I'm guessing that the surge protectors may have some partial leakage current, possibly just while they are clipping spikes, possibly all the time, and that's just enough to make the sensitive GFCIs trip even though there is no real danger at the time--just two gizmos with different agendas and different operating criterias. When surge protectors actually fail, they can do so in two different ways. They blow--like a fuse--or they slag down and become a dead short. In which case they often blow something else in fast order. Usually they just blow, like a fuse, and stop protecting anything.

You could probably take a $20 DMM and set it on the AC milliamps scale to measure any leakage current past the surge detector. If I remember, even 5mA of current will blow the GFCIs, and a good surge protector should have no leakage current at all.