Not earthing a generator

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Being no longer trusting that Energy Australia will supply power during
heatwaves, I've acquired a generator.

The manual advises connecting an earth tag on the generator to an earth
spike in the ground.

In the absence of this, since the generator is sitting on rubber-like
feet, it would appear to be pretty well insulated from the ground, and
running appliances off it would be akin to running them off an isolating
transformer.

What's the objection to running it this way?

Sylvia.

Re: Not earthing a generator

"Sylvia Else"
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** An isolating transformer normally only isolates the current carrying
conductors from ground while continuing the safety earth connection through
to the appliance.

Assuming that a portable generator has its neutral tied to the metal fame of
the machine, leakage ( or a short ) from active to the local ground would
make the frame live 240VAC.


.....  Phil






 



Re: Not earthing a generator
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Though I don't see what that achieves, other than ensure that there's no
static build up on the driven appliance.

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In this case, the generator has a plastic cover. The only places that
metal is exposed are the exaust, and the earthing point.

I'll find out whether its neutral is attached to its earth point when I
stop it later on. Damned thing needs to be run in for 20 hours at half
load before being used on variable loads, so I've got it warming up the
world through an electric bar heater.

Sylvia.

Re: Not earthing a generator

"Sylvia Else"

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** You don't see much at all.


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** Really .................

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** So one can get burnt and electrocuted at the same time.









Re: Not earthing a generator
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Oh Phil, you were doing so well. It was too much to hope that it would last.

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With sufficient determination, perhaps, if a fault of the particular
kind happens to develop in an appliance, the appliance's casing has
sufficient contact with ground and one goes out and touches the
generator's exaust outlet.

Sylvia.


Re: Not earthing a generator

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Hi Phil

I certainly see your point if the generator's neutral is tied to the
frame.

Is this common practice? If so, why?

I'm looking for enlightment, not an argument!

Cheers

Dave.

Re: Not earthing a generator

"Dave Goldfinch"
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** I believe it is the norm.

It duplicates the usual " earthed neutral " domestic AC supply and ensures
that a short from active to the protective earth of an appliance will trip a
breaker connected in the active.

So - if a gene's frame is NOT  grounded to real earth, a single fault (
where active leaks to real ground ) could render that frame live PLUS the
safety ground circuit of all the metalwork of any connected appliances that
use the safety ground conductor.

Absolutely lethal.


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** Makes a nice change round here.



....  Phil



Re: Not earthing a generator
Makes sense!

Thanks On Wed, 23 Feb 2011 19:15:05 +1100, "Phil Allison"

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Makes sense.

Thanks Phil.

Dave

Re: Not earthing a generator
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It's not on my generator.

Which would seem to mean that the output is floating compared with the
earth *pin*. That doesn't actually seem like a very good idea.

Sylvia.

Re: Not earthing a generator

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If it is bqasically a permanent installation, makes sense to drive an
earth spike or use the existing one.

Re: Not earthing a generator
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**Which one did you buy? How much power? Where'd you buy it? I hope you use
an inverter style air-con. Regular air-cons are deadly to generators.


--
Trevor Wilson
www.rageaudio.com.au



Re: Not earthing a generator
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After much soul searching I went for a Kipor GS2600 (rated output
2300W), bought from Sparky Direct. It may not (with emphasis on may)
have the run-time longevity of a Honda or Yamaha, but I don't need that
in this application. I'll probably die of old age before it reaches 50
hours. The twenty hour run-in, while a bit of a pain, gives me a chance
to let it burn-in while it's in warranty. I checked with Kipor in
Australia, and they claim that spare parts are available for it here.

In some quarters they seem to have a reputation for being a bit smokey,
but in fact once mine has warmed up, there's no smoke visible even if I
set out to look for it.

Yes, it's an inverter air-conditioner (Daikin). I called Daikin and they
hadn't a clue about starting current, so I measured it directly. It's
very well behaved.

I did some more searching regarding earthing. This seems to be a
contentious and hotly debated issue.

Sylvia.

Re: Not earthing a generator
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heatwaves, I've acquired a generator.
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in the ground.
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would appear to be pretty well insulated
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off an isolating transformer.
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some interesting reading here:
http://en.wikipedia.org/wiki/Earthing_system

If your generator walks, it may pay to anchor it in some way, if you end up
earthing it.
Perhaps even an earth anchor :-)


Cheers Don...

======================

--
Don McKenzie

Site Map:            http://www.dontronics.com/sitemap
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Re: Not earthing a generator
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Yes, having it walk onto the back of someone's truck is a particular
concern, and one that I've yet to resolve to my complete satisfaction.

Sylvia.

Re: Not earthing a generator

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Heavy metal strap bent into a U, two holes through it, then drive a
large pin through the holes into the ground. I make pins out of 1" reo
bar and a large washer. a number of those will slow down a stupid thief.

.

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