I recently acquired a small portable back up generator for nuisance
outages. Only paid $200 new. It is 2500 watts continuous, 3250 surge rated
and no 220 volt outlet, so I won't be hooking it up to a transfer switch.

Even though I'm going the extension cord method, I decided to properly
ground it, and use an inline GFI and surge protector. I'm willing to risk
using a back up computer with it, and I am hopeful that a surge protector
might clean up the "dirty" generator power.

Now the problem. I drove an 8 foot ground rod into typical soil, used a
correct copper clamp (nothing improvised), and connected the rod to the
generator ground lug with a single strand 12 gauge copper wire.

Trouble is, the generator outlets still tests as ungrounded.

I immediately suspected miswired outlets on the generator. So I tried
checking the resistance from the power receptacle outlet ground to both
the generator frame and the generator ground lug. Both tests resulted in
zero ohms of resistance. I'm thinking that would eliminate miswiring on
the generator as the cause.

I then removed both ends of the ground wire connection, checked and
reconnected them.

Same result, tests as open ground with a three prong plug in tester. I
also tested the tester, and it shows grounded outlets in my house as
properly grounded.

I checked the resistance from the generator end of the ground wire to the
ground rod itself. It was also zero ohms.

So it seems to be a case of it has to work, but it doesn't work. Any
suggestions are welcome.

--
Tony Sivori
Due to spam, I'm filtering all Google Groups posters.

On Sun, 15 Nov 2009 17:52:46 -0500, Tony Sivori
wrote:

I recently acquired a small portable back up generator for nuisance
outages. Only paid $200 new. It is 2500 watts continuous, 3250 surge rated
and no 220 volt outlet, so I won't be hooking it up to a transfer switch.

Even though I'm going the extension cord method, I decided to properly
ground it, and use an inline GFI and surge protector. I'm willing to risk
using a back up computer with it, and I am hopeful that a surge protector
might clean up the "dirty" generator power.

Now the problem. I drove an 8 foot ground rod into typical soil, used a
correct copper clamp (nothing improvised), and connected the rod to the
generator ground lug with a single strand 12 gauge copper wire.

Trouble is, the generator outlets still tests as ungrounded.

I immediately suspected miswired outlets on the generator. So I tried
checking the resistance from the power receptacle outlet ground to both
the generator frame and the generator ground lug. Both tests resulted in
zero ohms of resistance. I'm thinking that would eliminate miswiring on
the generator as the cause.

I then removed both ends of the ground wire connection, checked and
reconnected them.

Same result, tests as open ground with a three prong plug in tester. I
also tested the tester, and it shows grounded outlets in my house as
properly grounded.

I checked the resistance from the generator end of the ground wire to the
ground rod itself. It was also zero ohms.

So it seems to be a case of it has to work, but it doesn't work. Any
suggestions are welcome.

You may have high resistance soil, and need more than one ground rod.
Code typically calls for three, wired together.

In article ,
Tony Sivori wrote:

I recently acquired a small portable back up generator for nuisance
outages. Only paid $200 new. It is 2500 watts continuous, 3250 surge rated
and no 220 volt outlet, so I won't be hooking it up to a transfer switch.

Even though I'm going the extension cord method, I decided to properly
ground it, and use an inline GFI and surge protector. I'm willing to risk
using a back up computer with it, and I am hopeful that a surge protector
might clean up the "dirty" generator power.

Now the problem. I drove an 8 foot ground rod into typical soil, used a
correct copper clamp (nothing improvised), and connected the rod to the
generator ground lug with a single strand 12 gauge copper wire.

Trouble is, the generator outlets still tests as ungrounded.

I immediately suspected miswired outlets on the generator. So I tried
checking the resistance from the power receptacle outlet ground to both
the generator frame and the generator ground lug. Both tests resulted in
zero ohms of resistance. I'm thinking that would eliminate miswiring on
the generator as the cause.

I then removed both ends of the ground wire connection, checked and
reconnected them.

Same result, tests as open ground with a three prong plug in tester. I
also tested the tester, and it shows grounded outlets in my house as
properly grounded.

I checked the resistance from the generator end of the ground wire to the
ground rod itself. It was also zero ohms.

So it seems to be a case of it has to work, but it doesn't work. Any
suggestions are welcome.

It sounds as though the generator's neutral leg is not tied to ground at
the generator. The outlet tester isn't actually testing that the ground
prong is anywhere near ground, merely that current can flow between the
hot and the ground leg. (In a standard residential setup, the neutral
leg is tied to ground at the main breaker box, and all neutral and
ground wires go to the common neutral/ground bar. The outlet tester
would still show the outlet is wired properly even if the ground leg
were not actually connected to ground.)

By the way, the surge suppressor will do pretty much nothing to clean up
the generator output power. It's also rather likely that the output is
reasonably clean to begin with; certainly far better than a typical
"modified sine wave" inverter output, which is a combination of a couple
of square waves. A typical computer, with a switching power supply, is
not picky at all about power quality, as the first stage in the power
supply is a rectifier and reservoir capacitor, changing whatever the
input is into (unregulated) high voltage DC power. They run just fine
from the above mentioned modified sine wave inverters, potentially even
a bit more efficiently than from sinusoidal inputs.

Anyhow, you could tie the "neutral" leg of the generator output to
ground at the generator, which would be safe provided the generator
frame is actually grounded, and which would make the outlet tester
happier. Safer, IMHO, is just using the GFI and not worrying about it
more. Indeed, code permits GFIs to be used on existing ungrounded
circuits to allow three-pronged devices to be plugged in despite the
lack of a safety ground conductor (albeit with certain cautionary
labeling required).

--
Andrew Erickson

"He is no fool who gives what he cannot keep to gain that which he cannot
lose." -- Jim Elliot

PeterD wrote:

wrote:
So it seems to be a case of it has to work, but it doesn't work. Any
suggestions are welcome.

You may have high resistance soil, and need more than one ground rod.
Code typically calls for three, wired together.

I think you are probably right.

A quick Google shows that multiple ground rods are often necessary.
Although I found the NEC calls for multiple rods only when a single rod
installation exceeds it says 25 ohms. And it seems that every other
possible reason has been eliminated.

--
Tony Sivori
Due to spam, I'm filtering all Google Groups posters.

"Tony Sivori" wrote in message
news
PeterD wrote:

wrote:
So it seems to be a case of it has to work, but it doesn't work. Any
suggestions are welcome.

You may have high resistance soil, and need more than one ground rod.
Code typically calls for three, wired together.

I think you are probably right.

A quick Google shows that multiple ground rods are often necessary.
Although I found the NEC calls for multiple rods only when a single rod
installation exceeds it says 25 ohms. And it seems that every other
possible reason has been eliminated.

--
Tony Sivori
Due to spam, I'm filtering all Google Groups posters.

I think I know what the problem is. In a house, at the electrical panel,
the neutral wire is connected to the ground. Your tester maybe assuming
this and that is why it is not showing a ground connection. Your generator
probably has a floating output (neutral not connected to the frame ground).
Which is why the tested shows no ground. This will not pose a problem when
using the generator, it is still grounded, it's just that the neutral is not
connected to ground.

Shaun

Andrew Erickson wrote:

It sounds as though the generator's neutral leg is not tied to ground at
the generator. The outlet tester isn't actually testing that the ground
prong is anywhere near ground, merely that current can flow between the
hot and the ground leg.

I wasn't aware of that. Thanks.

(In a standard residential setup, the neutral leg is tied to ground at
the main breaker box, and all neutral and ground wires go to the common
neutral/ground bar.

That much I did know. I even knew that the only place the neutral can be
grounded is at the junction box.

The outlet tester would still show the outlet is wired properly even if
the ground leg were not actually connected to ground.)

A test with the outlet tester and an ungrounded outlet confirms that
you're right.

By the way, the surge suppressor will do pretty much nothing to clean up
the generator output power. It's also rather likely that the output is
reasonably clean to begin with; certainly far better than a typical
"modified sine wave" inverter output, which is a combination of a couple
of square waves. A typical computer, with a switching power supply, is
not picky at all about power quality, as the first stage in the power
supply is a rectifier and reservoir capacitor, changing whatever the
input is into (unregulated) high voltage DC power. They run just fine
from the above mentioned modified sine wave inverters, potentially even
a bit more efficiently than from sinusoidal inputs.

I've heard a few anecdotes of generator power damaging televisions and DVD
players. I thought a pair (one on each outlet) of cheap surge protectors
might help.

Anyhow, you could tie the "neutral" leg of the generator output to
ground at the generator, which would be safe provided the generator
frame is actually grounded, and which would make the outlet tester
happier.

Unless it would add safety, I'm not at all worried about bonding the
neutral to ground.

Safer, IMHO, is just using the GFI and not worrying about it
more. Indeed, code permits GFIs to be used on existing ungrounded
circuits to allow three-pronged devices to be plugged in despite the
lack of a safety ground conductor (albeit with certain cautionary
labeling required).

I may do that. One of the reasons I was dead set on proper grounding is
that I knew that the surge protectors can't work without a ground. If the
surge protectors are useless and unneeded, I could leave the ground
connected as is, and just use the inline GFI.

--
Tony Sivori
Due to spam, I'm filtering all Google Groups posters.

Shaun wrote:

I think I know what the problem is. In a house, at the electrical
panel, the neutral wire is connected to the ground. Your tester maybe
assuming this and that is why it is not showing a ground connection.
Your generator probably has a floating output (neutral not connected to
the frame ground). Which is why the tested shows no ground. This will
not pose a problem when using the generator, it is still grounded, it's
just that the neutral is not connected to ground.

You're right about the floating neutral.

I found a couple of OSHA pages discussing portable generator grounding and
neutral bonding.

http://www.osha.gov/OshDoc/data_Hurr..._generator.pdf

although it seems to contradict this one:

http://www.osha.gov/pls/oshaweb/owad...S&p_id =20448

--
Tony Sivori
Due to spam, I'm filtering all Google Groups posters.

On 11/15/2009 8:06 PM Tony Sivori spake thus:

Andrew Erickson wrote:

(In a standard residential setup, the neutral leg is tied to ground at
the main breaker box, and all neutral and ground wires go to the common
neutral/ground bar.

That much I did know. I even knew that the only place the neutral can be
grounded is at the junction box.

Don't say "junction box", as that statement will make all electricians
wince. You meant to say "breaker panel" or "distribution panel", right?


--
Who needs a junta or a dictatorship when you have a Congress
blowing Wall Street, using the media as a condom?

- harvested from Usenet

David Nebenzahl wrote:

On 11/15/2009 8:06 PM Tony Sivori spake thus:

Andrew Erickson wrote:

(In a standard residential setup, the neutral leg is tied to ground at
the main breaker box, and all neutral and ground wires go to the common
neutral/ground bar.

That much I did know. I even knew that the only place the neutral can be
grounded is at the junction box.

Don't say "junction box", as that statement will make all electricians
wince. You meant to say "breaker panel" or "distribution panel", right?

A slip of the tongue, or fingers, if you prefer.

I've found some more pages on the pros and cons of bonding a
portable generator floating neutral to ground.

http://blog.rv.net/2009/10/generator...and-grounding/

http://blog.rv.net/2009/10/portable-...tor-grounding/

--
Tony Sivori
Due to spam, I'm filtering all Google Groups posters.

On Nov 16, 5:58*am, Meat Plow wrote:
On Sun, 15 Nov 2009 22:17:57 -0500, Tony Sivori
wrote:

PeterD wrote:

wrote:
So it seems to be a case of it has to work, but it doesn't work. Any
suggestions are welcome.

You may have high resistance soil, and need more than one ground rod.
Code typically calls for three, wired together.

I think you are probably right.

A quick Google shows that multiple ground rods are often necessary.
Although I found the NEC calls for multiple rods only when a single rod
installation exceeds it says 25 ohms. And it seems that every other
possible reason has been eliminated.

And good luck trying to clean up the generator output if you intend on
using a UPS in the circuit. My generator is 2500/3250 surge like
yours. And it is brushless. But there was nothing I could do to filter
the output well enough where my two 1000va APC UPS units would come
back off battery. Both are used in my A/V gear after a about with
nuisance outages of short duration but short enough to need to reset a
lot of things. Also I had two 9 foot copper ground rods, one on either
side of the house connected inside to my ham radio stuff. When hooked
to an APC multi outlet filter with a wiring fault indicator, the
indicator did not light while on generator power. So I guess in my
case the two rods were enough. And they sure reduced my noise level on
the HF bands, the main reason for their installation.

If clean power is a requirement, can't you add inside your
'distribution panel' a couple of multistage EMI filters? Then, for
the 2kHz to 150kHz band, do your own?

Sequence is GEN, EMI Filter, EMI Filter, Custom Filter, your stuff
of course, put the breakers and over voltage in there in the
appropriate place.

EMI filters have Y caps, so...

In article ,
Tony Sivori wrote:

Even though I'm going the extension cord method, I decided to properly
ground it, and use an inline GFI and surge protector. I'm willing to risk
using a back up computer with it, and I am hopeful that a surge protector
might clean up the "dirty" generator power.

Not much. It may eliminate voltage spikes which rise significantly
above the nominal voltage level (although if there are enough of
these, they may burn up the MOV!). If it also has a "noise filter" in
it, it may reduce radio-frequency hash.

It will probably not, unfortunately, turn the rather ratty-looking
power waveform coming out of the generator into a clean sinusoid.

Now the problem. I drove an 8 foot ground rod into typical soil, used a
correct copper clamp (nothing improvised), and connected the rod to the
generator ground lug with a single strand 12 gauge copper wire.

Trouble is, the generator outlets still tests as ungrounded.

I immediately suspected miswired outlets on the generator. So I tried
checking the resistance from the power receptacle outlet ground to both
the generator frame and the generator ground lug. Both tests resulted in
zero ohms of resistance. I'm thinking that would eliminate miswiring on
the generator as the cause.

I then removed both ends of the ground wire connection, checked and
reconnected them.

Same result, tests as open ground with a three prong plug in tester. I
also tested the tester, and it shows grounded outlets in my house as
properly grounded.

The three-prong testers work by detecting the fact that the "ground"
and "neutral" wires are bonded together, back at the main
circuit-breaker panel. This allows a tiny trickle of current to flow
from the "hot" pin, through the neon bulb in the tester, to the
"ground" pin, and back to the panel via the ground wiring. [I infer
that this current flow isn't enough to trip any GFI in the circuit.]

The tester does not indicated "grounded" when you plug it into your
generator, because the generator does not strap its "neutral" and
"ground" together within the generator shell.

I understand that this is normal - that in a typical gas-powered
generator, the whole AC wiring system may be "floated" - it's
insulated away from ground. This actually decreases the shock
hazard... if you were to accidentally touch the "hot" lead, there
would be no way for current to flow through your body and back to
the generator via ground, since the generator doesn't connect ground
and neutral together.

I checked the resistance from the generator end of the ground wire to the
ground rod itself. It was also zero ohms.

In that case, your grounding arrangement is good.

I'd suggest checking your generator manual, to see if you can
determine whether it's designed to have a "floating neutral". I
suspect that it is. If so, don't modify it.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Tony Sivori wrote:
I may do that. One of the reasons I was dead set on proper grounding
is that I knew that the surge protectors can't work without a ground.
If the surge protectors are useless and unneeded, I could leave the
ground connected as is, and just use the inline GFI.

No relation to "wtom" ?

--
Best Regards:
Baron.

In article ,
Meat Plow wrote:

My generator is 2500/3250 surge like
yours. And it is brushless. But there was nothing I could do to filter
the output well enough where my two 1000va APC UPS units would come
back off battery.

I've read elsewhere that the problem with generators and UPS units, is
that the generator doesn't hold an exact 60 Hz. You might find a
generator's frequency will range as much as 63 Hz to 59 Hz from no load
to full load. The UPS likely depends on a crystal controlled oscillator
to determine if 60 Hz power is present.

I wonder if inverter generators like the little Honda EU1000i, will work
with a UPS?

Fred

On Mon, 16 Nov 2009 21:39:04 -0500, Fred McKenzie
wrote:

In article ,
Meat Plow wrote:

My generator is 2500/3250 surge like
yours. And it is brushless. But there was nothing I could do to filter
the output well enough where my two 1000va APC UPS units would come
back off battery.

I've read elsewhere that the problem with generators and UPS units, is
that the generator doesn't hold an exact 60 Hz. You might find a
generator's frequency will range as much as 63 Hz to 59 Hz from no load
to full load. The UPS likely depends on a crystal controlled oscillator
to determine if 60 Hz power is present.

I wonder if inverter generators like the little Honda EU1000i, will work
with a UPS?


Probably would work better. My UPS, a high end high power one, tells
me the line frequency on it's statistics page. Interesting watching
the statistics, and seeing line voltage variations, etc.

Meat Plow wrote:

On Sun, 15 Nov 2009 22:17:57 -0500, Tony Sivori
wrote:

PeterD wrote:

wrote:
So it seems to be a case of it has to work, but it doesn't work. Any
suggestions are welcome.

You may have high resistance soil, and need more than one ground rod.
Code typically calls for three, wired together.

I think you are probably right.

A quick Google shows that multiple ground rods are often necessary.
Although I found the NEC calls for multiple rods only when a single rod
installation exceeds it says 25 ohms. And it seems that every other
possible reason has been eliminated.

And good luck trying to clean up the generator output if you intend on
using a UPS in the circuit. My generator is 2500/3250 surge like yours.

Mine is a KingCraft from Aldi. Would you happen to have the same one?

And it is brushless. But there was nothing I could do to filter the
output well enough where my two 1000va APC UPS units would come back off
battery. Both are used in my A/V gear after a about with nuisance
outages of short duration but short enough to need to reset a lot of
things. Also I had two 9 foot copper ground rods, one on either side of
the house connected inside to my ham radio stuff. When hooked to an APC
multi outlet filter with a wiring fault indicator, the indicator did not
light while on generator power. So I guess in my case the two rods were
enough. And they sure reduced my noise level on the HF bands, the main
reason for their installation.

I'd guess that I'm grounded with the one 8 foot rod. I just didn't realize
how limited the cheap three prong outlet testers are. Live and learn.

--
Tony Sivori
Due to spam, I'm filtering all Google Groups posters.

Baron wrote:

Tony Sivori wrote:
I may do that. One of the reasons I was dead set on proper grounding is
that I knew that the surge protectors can't work without a ground. If
the surge protectors are useless and unneeded, I could leave the ground
connected as is, and just use the inline GFI.

No relation to "wtom" ?

wtom? Is that a nym?

--
Tony Sivori
Due to spam, I'm filtering all Google Groups posters.

Dave Platt wrote:

I'd suggest checking your generator manual, to see if you can determine
whether it's designed to have a "floating neutral". I suspect that it
is.
If so, don't modify it.

Not much in the manual. No mention of the floating neutral, just a
statement not to connect it directly to any structure's electrical system.

--
Tony Sivori
Due to spam, I'm filtering all Google Groups posters.

Tony Sivori wrote:

Baron wrote:

Tony Sivori wrote:
I may do that. One of the reasons I was dead set on proper grounding is
that I knew that the surge protectors can't work without a ground. If
the surge protectors are useless and unneeded, I could leave the ground
connected as is, and just use the inline GFI.

No relation to "wtom" ?

wtom? Is that a nym?


No. A troll.


--
The movie 'Deliverance' isn't a documentary!

Tony Sivori wrote:

Baron wrote:

Tony Sivori wrote:
I may do that. One of the reasons I was dead set on proper grounding
is that I knew that the surge protectors can't work without a
ground. If the surge protectors are useless and unneeded, I could
leave the ground connected as is, and just use the inline GFI.

No relation to "wtom" ?

wtom? Is that a nym?

A troll that jumped on anybody that mentioned surge protectors.

--
Best Regards:
Baron.

In article , Meat Plow
writes

And good luck trying to clean up the generator output if you intend on
using a UPS in the circuit. My generator is 2500/3250 surge like
yours. And it is brushless. But there was nothing I could do to filter
the output well enough where my two 1000va APC UPS units would come
back off battery.

There was a recent discussion in demon.tech.pc by someone with a very
similar problem. (If you're aware of w_tom, you'll not be surprised he
featured in that thread.) We managed to establish that some APC UPSes
are specified by APC as generator-compatible and also have a button on
the back which can be used to reduce the UPS's sensitivity to poor mains
voltage.

I told the OP in that thread that his problems may be due to the lack of
a ground reference, but not being au fait with the subject had to bow
out there. Bear in mind this was a 240V (UK) installation, so I wasn't
comfortable with discussing tying one side of the output to ground.

--
Mike Tomlinson