household ground system

[Arpit]

Hi, I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground. I think,
but Im not sure, that the ground for my house is a pipe at the side
stuck into the earth, and it looks a little dodgy. So I was thinking
of instlaling my own ground outside my room, in the form of 3 1.5
meter galvanised pipes in the ground. I'd then take a wire from each
and connect each wire to the ground pin of a standard plug. THen, I'd
put the 3 plugs into a 4 way power board, and plug the power board
into a wall outlet. the 4th socket would hold the plug for my UPS.

Are there any problems with multiple grounds for a house system?
POtential problems I can think of, would be

- galvanic corrosion of the ground electrodes
-ground loops
- melting of the powerboard lead iin case of a lightning strike

but I don't know enough aobut the above to come to a conclusion. COuld
anyone give me some advice please?

Thanks,
Arpit THomas

 

[Alan Peake]

Just on the subject of grounds, a few have quoted resistance figures for
grounding systems. How are they measuring that - i.e. between where and
where? I'm on a stand-alone solar system so I can't measure the resistance
from my earth stake to anything else except another earth stake and that's not
particularly low - especially in the lightning prone area I live in.
Alan

 

[Alan Peake]

The Bad news Is The Only way I know of for Measuring Ground Resistance is
with reference to ..... ground.
....
a more common way of measuring earth resistance is referencing to the MEN
earth ..... I guess both methods are out for you ;-(

Yes, but I did install two earth stakes - one next to the house and one next
to the shed which houses the solar stuff. So I can at least get some idea of
the ground conductivity (and it's not good!)
The two earths are connected underground and both house and shed are steel
framed so there shouldn't be too much P.D. between variuos points around the
place.

This may not be however as big an issue as you suspect with a stand alone
Solar installation Think about it .
The main Purpose of Earthing the System is in order to make sure that it
remains at Same or near same Potential as the rest of the geographical area

Yes, that's the general idea although I imagine the CMRR of the system may
not be high enough in the case of a direct hit on the house or shed.

Alan

 

[Alan Peake]

http://www.leminstruments.com/pdf/LEGP.pdf (page 14)
[or]

http://leminstruments.com/grounding_tutorial/html/index.shtml

Thanks for the references
Alan

 

[Alan Peake]

ahh but Contrary to lies told by w_tom Phone lines are not earthed there is
no reason for the Lightning to head for the Phone Lines - Lightning usually
heads in the opposite Direction that is from the Phone Lines to the Mains
Earth.

But if you don't have a mains earth? When my phone was installed, I had to
provide an earth stake and earth the shed that the phone was in. The next
point that the phone line get s close to ground is probably the RAM (Remote
Area Multiplexer) which is on a post on my boundary - 600M from the shed.
The line is buried 300mm but the soil conductivity is so poor that a
lightning strike nearby could do a bit of damage.
I haven't had a problem yet but a neighbour keeps getting his answering
machine blown up in electrical storms. His line is about 5km from the exchange.

Can you suggest a reasonable protection scheme for him? He's also on
stand-alone power.
Alan

 

[Alan Peake]

well in reality long experience (in the real world - Not in w_toms Fantasy
Land) shows that the only real effective protection is to unplug the
Answering machine from the Phone Line during a Thunderstorm. MOVs and Gas
discharge arrestors will provide some degree of protection for induced
currents during distant Strikes but given that the typical energy in a
Lightning Strike starts at 1,000,000,000 Joules and heads up to
10,000,000,000 Joules really when Lightning comes a calling it is pretty
well all over.

Regards
Richard Freeman

Yeah, that seems to be the only really reliable solution. Mind you, not
one that would be recommended by certain purveyors of preotection gear

Alan

 

[Alan Peake]

I claim that if sane and Informed precautions are taken you should
have no failures due to lighting also Real world information (rather
than lies and Fantasies) will enable you to make a informed Risk
assesment for those cases where it is not possible to take complete
precautions.

Regards
Richard Freeman

I suspect that thingo has had his wires crossed by reading some of the
literature put out by the LEM mob that he mentioned. I've seen some bad
technical writing, but this is appalling. Ever heard of "Inductivity" ?
Have a read at
http://leminstruments.com/grounding_tutorial/html/index.shtml
and you'll get the idea.
I'm not saying that what they are doing is incorrect but their explanations
leave much to be desired.
Alan

 

[Phil Allison]

"Arpit" <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in message

Hi, I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground.

** A UPS generates a new AC supply - so how will there be any spikes ???

I think,
but Im not sure, that the ground for my house is a pipe at the side
stuck into the earth, and it looks a little dodgy.

** Bits of pipe stuck in the ground may produce an electrically quieter
earth than the usual one - BUT there is no way the impedance to will be
as low.

You will be lucky if a short from a bit of pipe to the active even blows
the fuse.




............ Phil

 

[Rod Speed]

Arpit <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in
message news:ktet20hcd9hp7cm8u53nn8ak12joo739fi@4ax.com...

I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground.

You dont, actually. Thats always beena pig ignorant myth.

A decent UPS will get rid of differential mode spikes fine and
thats what the absolute vast bulk of spikes and surges are.

I think, but Im not sure, that the ground for my
house is a pipe at the side stuck into the earth,

Yes, thats the usual way its done.

and it looks a little dodgy.

In what way ?

So I was thinking of instlaling my own ground outside my room,
in the form of 3 1.5 meter galvanised pipes in the ground.

Pointless, wont help.

I'd then take a wire from each and connect each wire to
the ground pin of a standard plug. THen, I'd put the 3 plugs
into a 4 way power board, and plug the power board into a
wall outlet. the 4th socket would hold the plug for my UPS.

And that wont help either. The surge impedance will be much too high.

If you do want to do something about common
mode surges, you need to put that in the meter
box and that has to be done by a licensed electrician.

It makes a lot more sense to just makes sure that the
house insurance covers that sort damage instead.

Are there any problems with multiple grounds for a house system?

Nope, it just wont achieve anything useful.

POtential problems I can think of, would be

- galvanic corrosion of the ground electrodes

Sure, but galvanised pipe fixes that.

-ground loops

That wont happen in that situation.

- melting of the powerboard lead iin case of a lightning strike

Thats the main problem with doing it like that.

but I don't know enough aobut the above to come to a
conclusion. COuld anyone give me some advice please?

Dont bother, you're wasting your time.

 

[Arpit]

On Sun, 15 Feb 2004 12:14:48 +1100, "Phil Allison"
<philallison@optusnet.com.au> wrote:

"Arpit" <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in message



Hi, I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground.


** A UPS generates a new AC supply - so how will there be any spikes ???

sorry, what I bought was a SPS badged as a UPS

I think,
but Im not sure, that the ground for my house is a pipe at the side
stuck into the earth, and it looks a little dodgy.


** Bits of pipe stuck in the ground may produce an electrically quieter
earth than the usual one - BUT there is no way the impedance to will be
as low.

isn't the usual one a bit of pipe stuck in the ground? How will the
impedence of mine be higher than the original pipe?

You will be lucky if a short from a bit of pipe to the active even blows
the fuse.

Yep, a good system is typically 25 ohms, thats 10 amps at full line

voltage, so no fuse blowing. THe thing is , this new earth is in
addition to the old one, which is still connected to neutral at the
fuse box, so I expect the fuse will fail

........... Phil

 

[Arpit]

On Sun, 15 Feb 2004 12:43:58 +1100, "Rod Speed" <rod_speed@yahoo.com>
wrote:

Arpit <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in
message news:ktet20hcd9hp7cm8u53nn8ak12joo739fi@4ax.com...

I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground.

You dont, actually. Thats always beena pig ignorant myth.

A decent UPS will get rid of differential mode spikes fine and
thats what the absolute vast bulk of spikes and surges are.

hmm, ok. is lightning a differential mode spike? Id think not, but the
fact that neutral is connected to earth may change that? Its primarily
lighting I am concerned with, I lost a couple of hundred dollars of
equipment in the last storm.

I think, but Im not sure, that the ground for my
house is a pipe at the side stuck into the earth,

Yes, thats the usual way its done.

and it looks a little dodgy.

In what way ?

the wire to it doesnt even have any insulation and looks tarnished,
THe join between the pipe and the wire looks crusty.

So I was thinking of instlaling my own ground outside my room,
in the form of 3 1.5 meter galvanised pipes in the ground.

Pointless, wont help.


I'd then take a wire from each and connect each wire to
the ground pin of a standard plug. THen, I'd put the 3 plugs
into a 4 way power board, and plug the power board into a
wall outlet. the 4th socket would hold the plug for my UPS.

And that wont help either. The surge impedance will be much too high.

I'm not sure what exactly you mean by the surge impedance, but Im

assuming you mean the poor ability of the earth to take a large blast
of current sourced from elsewhere in the house, because of the thin
powerboard leads. Wouldnt the surge impedance be low on the actual
powerboard itself? THats really all Im concerned with.

If you do want to do something about common
mode surges, you need to put that in the meter
box and that has to be done by a licensed electrician.


It makes a lot more sense to just makes sure that the
house insurance covers that sort damage instead.

I'll look into that, thanks

Are there any problems with multiple grounds for a house system?

Nope, it just wont achieve anything useful.

POtential problems I can think of, would be

- galvanic corrosion of the ground electrodes

Sure, but galvanised pipe fixes that.

-ground loops

That wont happen in that situation.

- melting of the powerboard lead iin case of a lightning strike

Thats the main problem with doing it like that.

but I don't know enough aobut the above to come to a
conclusion. COuld anyone give me some advice please?

Dont bother, you're wasting your time.

 

[Phil Allison]

"Arpit" <DONTSPAMMEF00Lneko4@dodo.com.au

sorry, what I bought was a SPS badged as a UPS

** Standby Power Supply ????

I think,
but Im not sure, that the ground for my house is a pipe at the side
stuck into the earth, and it looks a little dodgy.


** Bits of pipe stuck in the ground may produce an electrically
quieter
earth than the usual one - BUT there is no way the impedance to will
be
as low.


isn't the usual one a bit of pipe stuck in the ground?

** It is linked to every other one in the vicinity via the common neutral
line.

Never heard of the MEN system ??

You will be lucky if a short from a bit of pipe to the active even blows
the fuse.

Yep, a good system is typically 25 ohms, thats 10 amps at full line
voltage, so no fuse blowing.

** You must be completely insane !!

What do you think that damn safety earth is for ????????????

A short from active to the safety earth MUST blow the AC supply fuse or
trip the breaker immediately or the metal case of some appliance could
become LIVE at 240 volts and stay live !!!!!!!

THe thing is , this new earth is in
addition to the old one,

** Then it is quite pointless.




.......... Phil

 

[Mike Harding]

On Sun, 15 Feb 2004 13:07:53 +1100, Arpit
<DONTSPAMMEF00Lneko4@dodo.com.au> wrote:

Yep, a good system is typically 25 ohms, thats 10 amps at full line
voltage, so no fuse blowing.

Perhaps I misunderstand you but from my time 25 years
ago in the UK (and other places) doing electrical work,
earth resistance (and it's resistance not impedance)
had to be less than 0R5 (half an ohm) for a domestic
installation. IIRC certain industrial installations could
be a bit more - but not a lot and certainly nowhere
near 25R!

Mike Harding

 

[GM]

"Mike Harding" <mike_harding1@nixspamhotmail.com> wrote in message
news:56ut20dl7s2ec4pl5vj0c5pe87q02s47an@4ax.com...

On Sun, 15 Feb 2004 13:07:53 +1100, Arpit
DONTSPAMMEF00Lneko4@dodo.com.au> wrote:

Yep, a good system is typically 25 ohms, thats 10 amps at full line
voltage, so no fuse blowing.

Perhaps I misunderstand you but from my time 25 years
ago in the UK (and other places) doing electrical work,
earth resistance (and it's resistance not impedance)
had to be less than 0R5 (half an ohm) for a domestic
installation.

No such reqirement here in OZ (for an MEN system anyway)

IIRC certain industrial installations could

be a bit more - but not a lot and certainly nowhere
near 25R!

Not a chance of seeing much less than 25 ohms more likely 100 plus in most
instances. (this is one of the resons MEN is used, athough i sometimes
wonder if it would be easier to have an isolated supply but lets not go into
that!)

Mike Harding

 

[Mike Harding]

On Sun, 15 Feb 2004 16:43:31 +1100, "GM"
<n0_SPamhathill2000@yahoo.com.au> wrote:

Perhaps I misunderstand you but from my time 25 years
ago in the UK (and other places) doing electrical work,
earth resistance (and it's resistance not impedance)
had to be less than 0R5 (half an ohm) for a domestic
installation.

No such reqirement here in OZ (for an MEN system anyway)

IIRC certain industrial installations could
be a bit more - but not a lot and certainly nowhere
near 25R!

Not a chance of seeing much less than 25 ohms more likely 100 plus in most
instances

I imagine that is due to the earth consistency and the very dry
ground in Oz? It was sometimes hard to achieve in the UK
but a little salt and water often helped at testing time

(this is one of the resons MEN is used

I think the UK has largely gone over to PME (Protective
Multiple Earth) ie. bonding of the earth to the neutral connector
at the supply connection point at the consumer premises,
these days - seems to work OK I understand but I guess a
broken neutral at the sub station transformer could cause
some issues - although it would also need a fault to occur
at that time - perhaps unlikely. ("We're sorry you died but
it was a very improbable event" .

athough i sometimes wonder if it would be easier to have
an isolated supply but lets not go into that!)

Could well be something in what you say.

Mike Harding

 

[GM]

"Mike Harding" <mike_harding1@nixspamhotmail.com> wrote in message
news:1b6u2096cdnaadhj9v86us2eu2v4neh986@4ax.com...

On Sun, 15 Feb 2004 16:43:31 +1100, "GM"
n0_SPamhathill2000@yahoo.com.au> wrote:

Perhaps I misunderstand you but from my time 25 years
ago in the UK (and other places) doing electrical work,
earth resistance (and it's resistance not impedance)
had to be less than 0R5 (half an ohm) for a domestic
installation.

No such reqirement here in OZ (for an MEN system anyway)

IIRC certain industrial installations could
be a bit more - but not a lot and certainly nowhere
near 25R!

Not a chance of seeing much less than 25 ohms more likely 100 plus in
most
instances

I imagine that is due to the earth consistency and the very dry
ground in Oz? It was sometimes hard to achieve in the UK
but a little salt and water often helped at testing time

(this is one of the resons MEN is used

I think the UK has largely gone over to PME (Protective
Multiple Earth) ie. bonding of the earth to the neutral connector
at the supply connection point at the consumer premises,
these days - seems to work OK I understand but I guess a
broken neutral at the sub station transformer could cause
some issues - although it would also need a fault to occur
at that time - perhaps unlikely. ("We're sorry you died but
it was a very improbable event" .

athough i sometimes wonder if it would be easier to have
an isolated supply but lets not go into that!)

Could well be something in what you say.

Mike Harding

Mike

Sounds like PME and MEN Multiple Earth/ed Neutral are one and the same
thing - The broken neutral problem you mention should not cause a rise in
the earth potential provided the three phase load on the sub is reasonably
balanced. (although depending on the 3 phase load balance, you may see a
change in the ditribution of the phase voltages.The LV mains(ie415/240) have
the neutral earthed on the supply poles as well as at each main switchboard
neutral link. I am trying to think what it would do to the level of fault
current that would flow if one phase was shorted to the now unbonded earth.
I think that there would still be a "virtual" neutral existing that would
cause the respective protection to operate. Anyone have any thoughts?

 

[Arpit]

On Sun, 15 Feb 2004 13:23:52 +1100, "Phil Allison"
<philallison@optusnet.com.au> wrote:

"Arpit" <DONTSPAMMEF00Lneko4@dodo.com.au

sorry, what I bought was a SPS badged as a UPS

** Standby Power Supply ????

it only starts its inverter when the power fails

I think,
but Im not sure, that the ground for my house is a pipe at the side
stuck into the earth, and it looks a little dodgy.


** Bits of pipe stuck in the ground may produce an electrically
quieter
earth than the usual one - BUT there is no way the impedance to will
be
as low.


isn't the usual one a bit of pipe stuck in the ground?


** It is linked to every other one in the vicinity via the common neutral
line.

Never heard of the MEN system ??

yeah, but if a lighting strikes a power pole in the same vicinity, the
neutral and the active are elevated in voltage. WHether or not thats a
concern, im unsure of.

You will be lucky if a short from a bit of pipe to the active even blows
the fuse.

Yep, a good system is typically 25 ohms, thats 10 amps at full line
voltage, so no fuse blowing.


** You must be completely insane !!

What do you think that damn safety earth is for ????????????

I mean without being connected to the neutral, just the pipe in the
ground.

A short from active to the safety earth MUST blow the AC supply fuse or
trip the breaker immediately or the metal case of some appliance could
become LIVE at 240 volts and stay live !!!!!!!


THe thing is , this new earth is in
addition to the old one,


** Then it is quite pointless.

hmm ok. So in MEN, if i have a poor earth but my neighbour has a good
earth, we are both ok?

......... Phil

 

[Phil Allison]

"Arpit" <

"Phil Allison"

** It is linked to every other one in the vicinity via the common
neutral
line.

Never heard of the MEN system ??


yeah, but if a lighting strikes a power pole in the same vicinity, the
neutral and the active are elevated in voltage.

** If lightening strikes a pole then the local GROUND voltage goes up
just as much as the A and N.

You will be lucky if a short from a bit of pipe to the active even
blows
the fuse.

Yep, a good system is typically 25 ohms, thats 10 amps at full line
voltage, so no fuse blowing.


** You must be completely insane !!

What do you think that damn safety earth is for ????????????


I mean without being connected to the neutral, just the pipe in the
ground.

** I give up.

A short from active to the safety earth MUST blow the AC supply fuse or
trip the breaker immediately or the metal case of some appliance could
become LIVE at 240 volts and stay live !!!!!!!


THe thing is , this new earth is in
addition to the old one,


** Then it is quite pointless.

hmm ok. So in MEN, if i have a poor earth but my neighbour has a good
earth, we are both ok?

** It means the neutral conductor stays no more than a few volts above
the local ground potential.

Microsecond duration spikes can still exist on A, N or E since any wire a
few metres long has enough inductance to make its impedance high to such
spikes.




............ Phil

 

[Rod Speed]

Arpit <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in
message news:38j030t4polq47bnsclajjetf9mv8asofq@4ax.com...

Phil Allison <philallison@optusnet.com.au> wrote
Arpit <DONTSPAMMEF00Lneko4@dodo.com.au wrote

sorry, what I bought was a SPS badged as a UPS

Standby Power Supply ????

it only starts its inverter when the power fails

Those are still called a UPS. Just one type of UPS basically.

I think, but Im not sure, that the ground for my house is a pipe
at the side stuck into the earth, and it looks a little dodgy.

Bits of pipe stuck in the ground may produce an
electrically quieter earth than the usual one - BUT
there is no way the impedance to will be as low.

isn't the usual one a bit of pipe stuck in the ground?

It is linked to every other one in the vicinity via the common neutral line.

Never heard of the MEN system ??

yeah, but if a lighting strikes a power pole in the same
vicinity, the neutral and the active are elevated in voltage.

Thats called a common mode surge. Its seen much less
often that differential mode surges and spikes where its
the difference between the active and neutral that spikes.

WHether or not thats a concern, im unsure of.

Yes, but that extra ground wont help with that.

You need the surge protector in the meter box with those.

And those surges are so rare in most areas that they
are hard to justify spending what you need to spend
to stop those that arent too close to the house.

You're better to make sure that the insurance covers it.

You will be lucky if a short from a bit of
pipe to the active even blows the fuse.

Yep, a good system is typically 25 ohms, thats
10 amps at full line voltage, so no fuse blowing.

You must be completely insane !!

What do you think that damn safety earth is for ????????????

I mean without being connected to
the neutral, just the pipe in the ground.

A short from active to the safety earth MUST blow the AC supply
fuse or trip the breaker immediately or the metal case of some
appliance could become LIVE at 240 volts and stay live !!!!!!!

THe thing is , this new earth is in addition to the old one,

Then it is quite pointless.

hmm ok. So in MEN, if i have a poor earth

Its unlikely that you do.

but my neighbour has a good earth, we are both ok?

Its undesirable to have a poor earth, but thats
for safety reasons, not for surges and spikes.

 

[Rod Speed]

Arpit <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in
message news:i7lt20502samtis7p08rfjrvmh6040f1l9@4ax.com...

Rod Speed <rod_speed@yahoo.com> wrote
Arpit <DONTSPAMMEF00Lneko4@dodo.com.au> wrote

I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground.

You dont, actually. Thats always beena pig ignorant myth.

A decent UPS will get rid of differential mode spikes fine and
thats what the absolute vast bulk of spikes and surges are.

hmm, ok. is lightning a differential mode spike?

Usually. Just not with very close lightning strikes.
And that extra earth spike wont help with those anyway.

Id think not, but the fact that neutral is
connected to earth may change that?

Yes, basically a very close lightning strike will see
all of the active, neutral and ground all surge.

Even the actual voltage of the physical dirt will too.
Which is why you sometimes see animals killed by
the substantial voltage between their feet.

Its primarily lighting I am concerned with, I lost a couple
of hundred dollars of equipment in the last storm.

Most of the damage is caused by differential mode surges.

Adding that extra grounds the UPS like you were
proposing wont help with a close lightning strike.

And wont help with a more distant lightning induced
differential surge either. The problem there is just
the big hike in the 240V seen for a short time.

I think, but Im not sure, that the ground for my
house is a pipe at the side stuck into the earth,

Yes, thats the usual way its done.

and it looks a little dodgy.

In what way ?

the wire to it doesnt even have any insulation and looks tarnished,

Thats fine, its copper. It doesnt need
to be insulated because its at ground.

THe join between the pipe and the wire looks crusty.

It probably isnt electrically tho. Thats likely just the
part that isnt in electrical contact between the wire
and the pipe. And its easy enough to redo that.

Get the electrician to do that when adding the high
current outlets in the garage. Wont cost much extra.

So I was thinking of instlaling my own ground outside my room,
in the form of 3 1.5 meter galvanised pipes in the ground.

Pointless, wont help.

I'd then take a wire from each and connect each wire to
the ground pin of a standard plug. THen, I'd put the 3 plugs
into a 4 way power board, and plug the power board into a
wall outlet. the 4th socket would hold the plug for my UPS.

And that wont help either. The surge impedance will be much too high.

I'm not sure what exactly you mean by the surge impedance,

Its the electrical impedance to the very sharp
voltage spike. Nothing like the DC impedance.

but Im assuming you mean the poor ability of the earth to take
a large blast of current sourced from elsewhere in the house,

From the active and maybe the neutral too.

because of the thin powerboard leads.

Its not the thickness that matters.

Wouldnt the surge impedance be
low on the actual powerboard itself?

Nope, because you've got all the wire between
there and where the lightning struck.

THats really all Im concerned with.

Sure, but that approach wont help.

If you do want to do something about common
mode surges, you need to put that in the meter
box and that has to be done by a licensed electrician.

It makes a lot more sense to just makes sure that the
house insurance covers that sort damage instead.

I'll look into that, thanks

It doesnt necessarily cost a cent.

Are there any problems with multiple grounds for a house system?

Nope, it just wont achieve anything useful.

POtential problems I can think of, would be

- galvanic corrosion of the ground electrodes

Sure, but galvanised pipe fixes that.

-ground loops

That wont happen in that situation.

- melting of the powerboard lead iin case of a lightning strike

Thats the main problem with doing it like that.

but I don't know enough aobut the above to come to a
conclusion. COuld anyone give me some advice please?

Dont bother, you're wasting your time.