GFCI Failures + Gadgets

[Spehro Pefhany]

On Tue, 18 Nov 2003 02:46:18 -0000, the renowned "Steve Sousa"
<etsteve@yahoo.com> wrote:

circuits it is illegal to use a GFCI breaker, like a refrigerator, or
a freezer.

Why?

I'd guess they did a study and concluded that more people would die of
food poisoning than would be saved from electrocution.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[David Lesher]

w_tom <w_tom1@hotmail.com> writes:

$5+ for a GFCI tester? Its nothing more than a switch and
maybe a 15K resistor that connects hot (black) wire to safety
ground (green) wire. That same tester is what the TEST button
does - already inside the GFCI.

The TEST button puts the R between Line Black and Load White, or
the inverse. This so TEST works on GFI's with no ground.
(At least on the ones I've fiddled with..)
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

 

[Gary Tait]

On Mon, 17 Nov 2003 22:03:14 GMT, "Jeff" <levy_jeff@hotmail.com>
wrote:

It would be incpnvenient to wait for the Poco to reset it. The best
thing would be a whole house GFCI, as is oftern used in most of the
rest of the world.

Whole house GFI? Where is this "rest of the world"? GFI'ing a whole house
would be stupid.

In actuality, they are often set up to protect only recptacle
circuits.

 

[Klaus Vestergaard Kragelu]

"Mark Jones" <127.0.0.1> wrote in message
news:2uOdnSWlSJSd3CSiRVn-sA@buckeye-express.com...

In news:3FB93DBE.447E6494@earthlink.net (Michael A. Terrell):
Gary Tait wrote:

On Mon, 17 Nov 2003 02:47:00 -0600, mr-mr-mr@mister.com wrote:

On Sat, 15 Nov 2003 15:44:40 -0700, Jim Thompson
invalid@invalid.invalid> wrote:

Went outside to add another electrical circuit at the BBQ and
discovered that all of my nice wire-tagging had faded to
non-readable.

So I couldn't figure out which common went with which hot.

Then it dawned on me to simply trip the GFCIs which releases *both*
hots and commons so a simple ohm-meter check would do the trick.

NOT! Both GFCIs wouldn't trip when I pressed the test buttons :-(

Went to Radio Shack and bought a Receptacle/GFCI tester for $5.99.

At the same time I noticed a gadget to locate breakers... bought it
also ($29.95).

Went home and tested the GFCIs... both have failed :-( Tester was
verified on some indoor GFCIs... it would trip them.

Both bad units are outdoors, so maybe it was the heat (they both face
the western sun... it gets over 120°F here . Any other ideas
about why they fail?

The breaker locator is neat... plug a sender unit into an outlet,
then scan the breakers... works like a champ.

...Jim Thompson


That is why the electric company should install a GFCI up on the pole
at the transformer. That way, everyone and everything is protected in
the whole neighborhood.

It would be inconvenient to wait for the Poco to reset it. The best
thing would be a whole house GFCI, as is oftern used in most of the
rest of the world.

So something minor happens, and all the lights go off? THIS IS A VERY
STUPID IDEA. The code here requires separate lighting and receptacle
circuits so the room doesn't go dark if you trip a breaker. Also, most
areas of a home do not need GFCI protection. Wet areas, areas with bare
concrete floors, or outdoors make sense. Some circuits it is illegal to
use a GFCI breaker, like a refrigerator, or a freezer.


Really. If we have to ground-fault an entire house (because the occupants
are too stupid and keep getting electrocuted to death) then maybe they
should just go live in a hut somewhere in Afghanistan, where there is
little
risk of electrocution?

I believe most european contries have a GFI, certainly we have them in
Denmark where I live. I'm very happy we have those installed in the main
power inlet because it is a lifesafer. Many houses fail to have correct or
even installed ground/earth protection at all (before 1970 or thereabouts it
was not illegal to run appliances without earting). In these cases the GFI
serves a great purpose and which is why it was installed in the first place

I have only experience lightning strikes mistakenly triggering the GFI
two/three times over 30 years, so I see no reason to apply them only to
certain areas in the house. The only times I have been bothered by the GFI
is when I'm doing experiements in my lab, and in these cases I have been
surprised sometimes because I did something stupid (like connecting the
scope to the phone wire, tripping the GFI because the phoneline neutral is
grounded also)

Cheers

Klaus

 

[David Lesher]

"Steve Sousa" <etsteve@yahoo.com> writes:

We have that too. Different breakers for lighting and receptacles.

More info: country is Portugal, Here we have the meter, followed by a big
breaker that is also a GFI (which we call "differential breaker") outside
the house/apartment, the differential fault current is 500mA and overcurrent
is settable from 10 to 30 Amps, according to hired power.

Then, inside the house there is the main panel with a smaller breaker/gfi
that feeds all the circuit breakers. Mine is 30mA, way too high, in my
experience. Lights and receptacles have to be on different circuits. Power
is 3 phase at least for most houses, i'm not sure about apartments.

It's clear your codes are far stiffer than ours.

But part of it is we have a different approach. By making individual
GFI's near the load, we have a lower setpoint than you can have for
the whole house.

We do not, as far as I know, require separate circuits for residence
lighting & outlets; in many rooms, the only lamps plug into outlets.
Sometimes the outlets are switched. (Commercial building DO have
separate circuits.)

Virtually no residence in the US has 3-phase. Considering the US's
saturation of whole house air conditioning, we would do better if
we did. Does your home have AC/electric heat?

In general, the code required is the one in effect when the house
was wired, or last rewired. When the code changes, the house does
not; it is "grandfathered" in to the old standard. Is that true
there?
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

 

[Steve Sousa]

David Lesher wrote:

Hi:

"Steve Sousa" <etsteve@yahoo.com> writes:
It's clear your codes are far stiffer than ours.

But part of it is we have a different approach. By making individual
GFI's near the load, we have a lower setpoint than you can have for
the whole house.

I like the ideia of having more GFIs but this is not usually done as they
are expensive, i think they are putting one for the bathrooms now, but i'm
not sure. Only the whole house one is mandatory.

Virtually no residence in the US has 3-phase. Considering the US's
saturation of whole house air conditioning, we would do better if
we did. Does your home have AC/electric heat?

We use mostly electric space heaters, and the electrical water heater is as
common as the gas one. However about 5 years ago the country had a network
of natural gas installed and 99% of all houses build now come pre-equiped to
use gas for central-heating.

Regarding 3 phase, I believe that the main reason is that until some 15
years ago all houses had their own well(sp?) and the water-pump motor was
always 3 phase. The evolution was: people had their fields, then electricity
came and most people got a water-pump for the field, then houses were build
on those fields, etc. But it's also a "policy" because 3 phase is more
balanced, doesn't need so heavy wiring, specially if you consider that all
the old houses had fuses, not breakers. Now i have 3x15Ax230V=10350W. I
would need 45A breakers and wiring otherwise, quite a difference. However in
most other aspects the code is very poor, like inspections, what's not
allowed, etc. Yours is much more detailed.

In general, the code required is the one in effect when the house
was wired, or last rewired. When the code changes, the house does
not; it is "grandfathered" in to the old standard. Is that true
there?

Yes, i think you can still have a wiring box with just fuses! But hey, they
did update the meters to new models a few years ago... ;-)

--
Steve Sousa

 

[Chuck Harris]

David Lesher wrote:

"Steve Sousa" <etsteve@yahoo.com> writes:



We have that too. Different breakers for lighting and receptacles.


More info: country is Portugal, Here we have the meter, followed by a big
breaker that is also a GFI (which we call "differential breaker") outside
the house/apartment, the differential fault current is 500mA and overcurrent
is settable from 10 to 30 Amps, according to hired power.


Then, inside the house there is the main panel with a smaller breaker/gfi
that feeds all the circuit breakers. Mine is 30mA, way too high, in my
experience. Lights and receptacles have to be on different circuits. Power
is 3 phase at least for most houses, i'm not sure about apartments.


It's clear your codes are far stiffer than ours.

The european codes have to be much stiffer than the US, it makes up for
their stupid decision of bringing 240V into every socket in the house.

It is quite rare for anyone to die when they accidentally come into
contact with the US "max 120V to earth ground" residential electrical
system.

120V is low enough that dry skin resistance performs a protective
function, and limits how much current can get to the core of your
body... to a highly uncomfortable, but usually non fatal amount.

240V is high enough so that the dry skin resistance is never enough
to protect the core of the body from receiving a fatal amount of
current.

And yes, I know that the lethality of current passing through the core
of your body depends on what organs it does, or does not pass through.

-Chuck

 

[Mark Jones]

In news:3fba991f$0$9750$edfadb0f@dread14.news.tele.dk (Klaus Vestergaard
Kragelund):

"Mark Jones" <127.0.0.1> wrote in message
news:2uOdnSWlSJSd3CSiRVn-sA@buckeye-express.com...
In news:3FB93DBE.447E6494@earthlink.net (Michael A. Terrell):
Gary Tait wrote:

On Mon, 17 Nov 2003 02:47:00 -0600, mr-mr-mr@mister.com wrote:

On Sat, 15 Nov 2003 15:44:40 -0700, Jim Thompson
invalid@invalid.invalid> wrote:

Went outside to add another electrical circuit at the BBQ and
discovered that all of my nice wire-tagging had faded to
non-readable.

So I couldn't figure out which common went with which hot.

Then it dawned on me to simply trip the GFCIs which releases *both*
hots and commons so a simple ohm-meter check would do the trick.

NOT! Both GFCIs wouldn't trip when I pressed the test buttons :-(

Went to Radio Shack and bought a Receptacle/GFCI tester for $5.99.

At the same time I noticed a gadget to locate breakers... bought it
also ($29.95).

Went home and tested the GFCIs... both have failed :-( Tester was
verified on some indoor GFCIs... it would trip them.

Both bad units are outdoors, so maybe it was the heat (they both
face the western sun... it gets over 120°F here . Any other
ideas about why they fail?

The breaker locator is neat... plug a sender unit into an outlet,
then scan the breakers... works like a champ.

...Jim Thompson


That is why the electric company should install a GFCI up on the
pole at the transformer. That way, everyone and everything is
protected in the whole neighborhood.

It would be inconvenient to wait for the Poco to reset it. The best
thing would be a whole house GFCI, as is oftern used in most of the
rest of the world.

So something minor happens, and all the lights go off? THIS IS A
VERY STUPID IDEA. The code here requires separate lighting and
receptacle circuits so the room doesn't go dark if you trip a
breaker. Also, most areas of a home do not need GFCI protection. Wet
areas, areas with bare concrete floors, or outdoors make sense. Some
circuits it is illegal to use a GFCI breaker, like a refrigerator, or
a freezer.


Really. If we have to ground-fault an entire house (because the
occupants are too stupid and keep getting electrocuted to death) then
maybe they should just go live in a hut somewhere in Afghanistan,
where there is little risk of electrocution?


I believe most european contries have a GFI, certainly we have them in
Denmark where I live. I'm very happy we have those installed in the main
power inlet because it is a lifesafer. Many houses fail to have correct
or even installed ground/earth protection at all (before 1970 or
thereabouts it was not illegal to run appliances without earting). In
these cases the GFI serves a great purpose and which is why it was
installed in the first place

I have only experience lightning strikes mistakenly triggering the GFI
two/three times over 30 years, so I see no reason to apply them only to
certain areas in the house. The only times I have been bothered by the
GFI is when I'm doing experiements in my lab, and in these cases I have
been surprised sometimes because I did something stupid (like
connecting the scope to the phone wire, tripping the GFI because the
phoneline neutral is grounded also)

Cheers

Klaus

Interesting. All of the wiring in my house when it was built in the 60's
was all non-grounded. Uses the round branch fuses... Since then a lot of the
wiring has been upgraded, but even now some outlets are not grounded
properly, and there is no GFCI's in any room. In the garage, the outlets are
grounded to a metal rod in the ground, which barely passes as a ground,
especially when cutting steel with a 380v cutter...

A whole-house GFCI would be a nightmare for my residence. Some drills and
other power tools out in the garage are the old metal ones, which do leak
some parasitic conductance. I'm sure if my whole house was GFCI'd, I'd have
a remote-reset for it....

 

[modervador]

In sci.electronics.design Fred Abse <excretatauris@cerebrumconfus.it> wrote:
On Sat, 15 Nov 2003 20:18:15 -0500, Gary Tait wrote:

It will, the test button on a GFCI usually, through a resistor, connects
the GFCI protected hot to the unprotected neutral.

That's just the same as loading the circuit, it won't work. GFCIs monitor
current in *both* hot and neutral, which should be the same.

You need to create an imbalance current by introducing a resistance
between hot and *ground* 5mA might do it. 30mA _must_ do it, or the
protection is no damn good.

GFCIs monitor current in hot and neutral *after* the (unprotected)
line input. You can create an imbalance current by introducing a
*finite resistance[1]* between protected (load side) hot and
*unprotected (line side) neutral*. That's how the GFCI test button
works, with no connection to ground (witness the 2 prong GFCI in hair
dryer plugs). It is not the same as simply loading the circuit. A GFCI
tester that could not access the unprotected neutral would have to use
some other path, ground being the most convenient.

%mod%

[1] An open circuit is infinite resistance.

 

[Louis Bybee]

"modervador" <modervador@worldnet.att.net> wrote in message
news:842f31a0.0311191248.635f6c0a@posting.google.com...

In sci.electronics.design Fred Abse <excretatauris@cerebrumconfus.it
wrote:
On Sat, 15 Nov 2003 20:18:15 -0500, Gary Tait wrote:

It will, the test button on a GFCI usually, through a resistor,
connects
the GFCI protected hot to the unprotected neutral.

That's just the same as loading the circuit, it won't work. GFCIs
monitor
current in *both* hot and neutral, which should be the same.

You need to create an imbalance current by introducing a resistance
between hot and *ground* 5mA might do it. 30mA _must_ do it, or the
protection is no damn good.

GFCIs monitor current in hot and neutral *after* the (unprotected)
line input. You can create an imbalance current by introducing a
*finite resistance[1]* between protected (load side) hot and
*unprotected (line side) neutral*. That's how the GFCI test button
works, with no connection to ground (witness the 2 prong GFCI in hair
dryer plugs). It is not the same as simply loading the circuit. A GFCI
tester that could not access the unprotected neutral would have to use
some other path, ground being the most convenient.

%mod%

[1] An open circuit is infinite resistance.

There is no such thing as "infinite" resistance!

With the appropriate instrumentation any resistance could be quantified.
What you think of, or even measure, as an open circuit, is merely a circuit
which has exceeded your, or your instrument's, ability to measure. :-]

Louis--
*********************************************
Remove the two fish in address to respond

 

[John Woodgate]

I read in sci.electronics.design that Louis Bybee <louistroutbybee@comca
sttrout.net> wrote (in <MVQub.190487$275.636131@attbi_s53&gt about 'GFCI
Failures + Gadgets', on Wed, 19 Nov 2003:

There is no such thing as "infinite" resistance!

Quite right. I have a very old (well, around 50 years) Twenty Million
Megohmmeter. I don't suppose the EF37As still have low enough grid
current. (;-) I keep it for the huge meter, which I can't bear to throw
away.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

 

[Gary Tait]

On Wed, 19 Nov 2003 11:56:54 -0500, Chuck Harris <cfharris@erols.com>
wrote:

The european codes have to be much stiffer than the US, it makes up for
their stupid decision of bringing 240V into every socket in the house.

240V, IMO, is a good thing, needs less copper per watt delivered. That
way, you can have more than 1500W appliances, without a special outlet
installed.

 

[Tony Hwang]

Gary Tait wrote:

On Wed, 19 Nov 2003 11:56:54 -0500, Chuck Harris <cfharris@erols.com
wrote:


The european codes have to be much stiffer than the US, it makes up for
their stupid decision of bringing 240V into every socket in the house.


240V, IMO, is a good thing, needs less copper per watt delivered. That
way, you can have more than 1500W appliances, without a special outlet
installed.

Hi,
I agree. In Korea, they switched to higher voltage. More economical!
By law, they can't make and sell 120V stuffs for domestic use there.
EC spec. is more strict in many things. For an example, look at the
spec. for PC or laptop power supplies. Better spec. for frequency,
voltage, noise, etc. Their TV(PAL) is better too, at least until HDTV
takes over.
Tony

 

[Tim Auton]

Gary Tait <classicsat@yahoo.cominvalid> wrote:

On Wed, 19 Nov 2003 11:56:54 -0500, Chuck Harris <cfharris@erols.com
wrote:
The european codes have to be much stiffer than the US, it makes up for
their stupid decision of bringing 240V into every socket in the house.

240V, IMO, is a good thing, needs less copper per watt delivered. That
way, you can have more than 1500W appliances, without a special outlet
installed.

I don't know about the wire gauges used in household electrics, but
are you saying 110V kettles are no more than 1500W? Sheesh, no wonder
Americans don't drink tea


Tim
--
And the beast shall be made legion. Its numbers shall be increased a
thousand thousand fold. The din of a million keyboards like unto a great
storm shall cover the earth, and the followers of Mammon shall tremble.
- The Book of Mozilla, 3:31

 

[Dbowey]

re: >There is no such thing as "infinite" resistance!

----

picky, picky.

 

[Gary Tait]

On Thu, 20 Nov 2003 01:38:16 +0000, Tim Auton <tim.auton@uton.[group
sex without the y on the end]> wrote:

Gary Tait <classicsat@yahoo.cominvalid> wrote:
On Wed, 19 Nov 2003 11:56:54 -0500, Chuck Harris <cfharris@erols.com
wrote:
The european codes have to be much stiffer than the US, it makes up for
their stupid decision of bringing 240V into every socket in the house.

240V, IMO, is a good thing, needs less copper per watt delivered. That
way, you can have more than 1500W appliances, without a special outlet
installed.

I don't know about the wire gauges used in household electrics, but
are you saying 110V kettles are no more than 1500W? Sheesh, no wonder
Americans don't drink tea


Tim

Something like that, as domestic outlets supply 1800W or so, and can
only be loaded to 80% of it's ampacity.

 

Jeff wrote:

ehsjr@bellatlantic.net> wrote in message
news:3FB8763D.57766474@bellatlantic.net...


Jeff wrote:



Breakers are the best,

Why are breakers the best?

Because GFI breakers are at the panel, and all wiring, outlets, accessories,
etc are protected, not just the ones after the GFI outlet.

Ok, I see. It's not that the breaker is better, per se, it
is the position it occupies in the circuit.

GFI breakers
should be more reliable, especially since they are in a usually fairly
controlled environment.

Ok - that's a technical reason for breakers over receptacles
but only if it is true. Are GFCI breakers known to be more
reliable then GFCI receptacles, to your knowledge?

GFI breakers are also located in one spot - if a GFI
plug trips from an outlet later on in the circuit, then there may be some
difficulty in locating which GFI outlet tripped, or if a normal breaker
tripped from over current.

So that falls under "easier to use" (or whatever you
want to call it.)


Thanks! I don't necessarily agree that the points you
raised make a GFI breaker better than a GFCI receptacle,
but I can appreciate your rationale.

 

w_tom wrote:

Good idea if only using theoretical knowledge.

It is a horrible idea, even if using only theoretical
knowledge. I suspect that you have something different
in mind when you say theoretical knowledge. I'm using
it to mean the things below:

The pole feed will rarely, if ever, have equal
currents on the two hots and the neutral. If a different
design was used that did not depend on imbalance, there is
still the problem of tripping at 5 mA ground current to
protect people. One could easily have 5 mA current to
ground on one total service with no fault - and he's
talking about protecting multiple services. False trips
would be common. If the trip level was set higher, then
there could be a current at that higher level through a
person into ground. The size of the contacts would have
to be enormous to handle the current.

Bad in
reality. It is a classical example of why decisions based only
upon theory are not sufficient. It is why they teach in high
school science the concepts. Required is both the theoretical
concepts AND experiment confirmation. Why is the refrigerator,
specifically demanded by code, not on a GFCI? Because GFCIs
are good in some places and not desirable in others - as has
been proven by experience. A blown GFCI on a refrigerator can
create food poisoning - something learned by field
experiments.

mr-mr-mr@mister.com wrote:
That is why the electric company should install a GFCI up on the
pole at the transformer. That way, everyone and everything is
protected in the whole neighborhood.

 

[Tim Auton]

Gary Tait <classicsat@yahoo.cominvalid> wrote:

On Thu, 20 Nov 2003 01:38:16 +0000, Tim Auton <tim.auton@uton.[group
sex without the y on the end]> wrote:
[snip]
I don't know about the wire gauges used in household electrics, but
are you saying 110V kettles are no more than 1500W? Sheesh, no wonder
Americans don't drink tea

Something like that, as domestic outlets supply 1800W or so, and can
only be loaded to 80% of it's ampacity.

You can take my 3kW kettle from my cold, dead hand!


Tim
--
And the beast shall be made legion. Its numbers shall be increased a
thousand thousand fold. The din of a million keyboards like unto a great
storm shall cover the earth, and the followers of Mammon shall tremble.
- The Book of Mozilla, 3:31

 

Gary Tait wrote:

On Mon, 17 Nov 2003 22:03:14 GMT, "Jeff" <levy_jeff@hotmail.com
wrote:


It would be incpnvenient to wait for the Poco to reset it. The best
thing would be a whole house GFCI, as is oftern used in most of the
rest of the world.

Whole house GFI? Where is this "rest of the world"? GFI'ing a whole house
would be stupid.


In actuality, they are often set up to protect only recptacle
circuits.

What does the word "they" refer to - a "whole house GFCI" ??

In actuality, there is no such thing that could be set up
to protect only receptacle circuits. You can protect 1 branch
circuit at a time with a GFI breaker or a GFCI receptacle.
With a GFCI receptacle, you can also protect only a part of
the circuit. A GFCI receptacle can be installed such that it
protects all outlets wired downstream of it, or only itself.
There's no such thing as a "whole house GFCI" in any event.