Author Topic: Portable Generators  (Read 546 times)

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Offline Pete

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Portable Generators
« on: June 14, 2018, 05:21:32 pm »
Hello folks, I just wanted to share a problem I found with a brand new portable generator I have.
About a year ago I purchased a 6.8 kva Honda powered generator. It came with two power outlets and an RCD (safety switch). It is a great unit for what I wanted it to do, which is to power my PowerJack as a battery charger on rare occasions and to run large power tools.
I have only used it to run power tools up until now, but as I have moved to the mountains and we get a lot of rain and fog in winter, I had a reason to plug in the powerjack.
Well as soon as I turned plugged the powerjack into the generator and turned it on the circuit breaker tripped.
I originally thought that the fault was caused by the RCD on the generator not liking feeding into the RCD of my shed and house wiring.
So I set about rewiring one of the generator power points so that it was not RCD protected. That worked fine.
I then decided to plug in my RCD checker and test that the RCD actually worked. It did not, not only that but the tester showed that the Active and Neutral were tranposed.
So I pulled the covers off and looked at the wiring again, only to find that from new the generator power outlets had the Neutral in the Active terminal and vice versa.
There prominently displayed was a sticker saying Tested OK.
Well the test must be pretty cursory.
I just wanted to warn folks that this is something worth checking on their portable generators. It can lead to very dangerous conditions.
Cheerio
Pete

Offline DJ

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Re: Portable Generators
« Reply #1 on: June 19, 2018, 10:43:23 am »

 I wonder if the outlets were factory Fitted or were done by the importer?
Spose anyone in a factory doing the same thing day in, day out can have an off day too.

There are some importers here claiming they have Honda engines fitted to their equipment with authentic looking Honda stickers which are actually Chinese Knockoffs. Don't know how they are getting away with it but they have for a while now.

Offline Pete

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Re: Portable Generators
« Reply #2 on: June 19, 2018, 05:22:19 pm »
Hi DJ the outlets look like they are factory jobs. They are mounted in a metal box that is welded to the generator frame. Each outlet has an overload circuit breaker plus they are both controlled by an RCD. The wiring looked factory , even had an OK sticker inside the box at the back of the power outlets. Just that the neutrals were in the active terminals and vice versa.
One odd thing is that the brands are Chinese looking. Instead of using "Clipsal" ( a very common major brand here in OZ) outlets they are branded "Clipal".
Like you say it is hard to understand how they get away with it.
The engine says Honda but like you say who knows these days.
The generator is branded GENESYS 8000. In fact it is a 6.5 kva generator. I don't know how they go branding generators on their short term surge power either.
We live in a world flooded with subterfuge
Cheerio
Pete

Offline MadScientist267

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Re: Portable Generators
« Reply #3 on: June 23, 2018, 01:33:39 am »
I don't usually advocate circumventing certain things, but in the case of a portable generator, "ground" is a pretty loose concept anyway, and really doesn't mean a whole lot...

Have you considered simply establishing your own reference downstream of the genset? It isn't like RCD/GFI requires a reference to actually operate... Personally I'd keep it in the mix and just take away the power and bond the system ground downstream. Hot and neutral are really only what they are because of a definition (determined by the bond)... especially in a genset. So really, there's no such thing as "reversed" in that case. This isn't to say I don't understand your findings, just that there are simple ways of working around it (one viable means, being what you've already done)

Like I said, not really advocating defeating anything, but when there's not really anything to "defeat"... know what I mean?

I've seen arguments on both sides of the fence when it comes to how to handle grounds and portable gensets. My stance is "float". Reference it correctly to itself but carry the power away without it.

This is essentially what was done with the truck genset... The actual OEM ground connection isn't anything more than a bond to the engine, which I discovered wasn't part of anything else anyway in that particular case, so trying to sink errant current into ground downstream doesn't do anything but make the internal chassis go hot to whatever degree. In my unit, there's also not really any exposed metal anyway aside from the plate the outlets are mounted to, the rest is all sheathed in plastic. I ran ground bonds out with the original intent of bonding truck frame and genset engine together but decided last minute this would mean precisely squat, and in the event of a fault, would only serve to cause possible internal damage to the generator. Instead, I only take away the 120 and established the ground for it on the power board. Hasn't been any issue with doing so.

Also, my genset doesn't have RCD/GFI built in, but I used them downstream. They've saved my neck at least once, so I absolutely don't recommend going without them, just possibly "relocating" their position electrically in the system, depending on need.

Either way, it's not a willy nilly consideration. Safety should of course remain a top priority, whatever form that takes.

(Put another way, don't listen to me lol)   ;D

Steve
Wanted: Schrödinger's cat, dead and alive.

Offline Pete

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Re: Portable Generators
« Reply #4 on: June 23, 2018, 05:23:32 pm »
Hi Steve, that is basically what i have. I have RCD's on the house and shed switchboards. The genset is plugged into my PowerJack, using it as a battery charger. So I have two power points on the genset, one with RCD one without. With the connections as they were as soon as I turned the gene power on to the Powerjack the breaker blew. I guess it did not like feeding 240 volts directly to ground. ( the powerjack frame is earthed and neutral is tied to ground as well)
I tested the RCD operation on the Genset and with the Active and Neutrals reversed on the power points it did not work at all. Once I put them the right way round the safety switch operated.
The main thing with reversing the Active and Neutral at the powerpoints is that anything downstream then switches the neutral not the active.
If someone were crazy enough to stick a knife in their toaster for instance to get stuck toast out then they would receive flying lessons.
Really my post was a warning of just how dodgy the stuff coming out of China is these days.
Cheers  hope truck life is good
Pete

Offline MadScientist267

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Re: Portable Generators
« Reply #5 on: June 23, 2018, 08:16:05 pm »
I hear that. Definitely agree I've seen some shady crap come from them as well.

Truck's fine, although I haven't been spending much time in it lately... probably going to bring it to a close before long, open some new chapters ;)

Steve
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