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Message |
John Woodgate
Guest
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 Posted:
Sat Feb 12, 2005 3:45 am Post subject:
Re: 110V ac |
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I read in sci.electronics.design that John Larkin <jjlarkin@highSNIPland
THIStechPLEASEnology.com> wrote (in <gt6q0194pak21vuu69529hkk6pbd0de5sd@
4ax.com>) about '110V ac', on Fri, 11 Feb 2005:
| Quote: | Do fusebox GFD's false-trip a lot? We have them in outlets in the
kitchen, bathrooms, and garage, anywhere potentially wet, and certain
brush-motor-type appliances tend to trip them; slows me down grinding
coffee sometimes. Sometimes they just trip, probably from transients
somewhere.
I measured 5 megs leakage on my garbage disposal, and that was enough to
trip a GFD. I also had a sump pump (the lower level of my house is below
the street, so we have to pump stuff up from the lower bathroom) that
tripped its GFD from a tiny bit of leakage.
|
It sounds as though you have voltage-sensing devices. In Europe we now
have differential current-sensing devices - Residual Current Circuit
Breakers - with controlled operating currents, such as 10 mA and 30 mA.
The latter are normally used, ad protect very well against life-
endangering shock while minimising nuisance tripping.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
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Ken Taylor
Guest
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| Posted:
Sat Feb 12, 2005 6:07 am Post subject:
Re: 110V ac |
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"John Larkin" <jjlarkin@highSNIPlandTHIStechPLEASEnology.com> wrote in
message news:gt6q0194pak21vuu69529hkk6pbd0de5sd@4ax.com...
| Quote: | On Sat, 12 Feb 2005 09:21:03 +1300, "Ken Taylor" <ken@home.nz> wrote:
"John Larkin" <jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX> wrote in
message news:eplo01dhdo1oepvdpf1qk9tfqcoa9p2dp5@4ax.com...
On Fri, 11 Feb 2005 05:58:01 +0000, Pooh Bear
rabbitsfriendsandrelations@hotmail.com> wrote:
John Larkin wrote:
Here we have residential 120-0-120 power. In my old house, a 100+
year-old Victorian, we had an intermittent open neutral (that's the
0v
line in the middle) out on the pole outside. That caused interesting
effects, as about half the 120-volt devices in the house were then
operating in series with the other half, off 240 volts.
That sounds entertaining !
How common is 'power off the pole' in the US ?
We only see it here in the UK in remote rural areas.
Incidentally, your house must be around the same age as mine - 113 yrs
old here.
Whereabouts is that ?
Holly Park neighborhood of San Francisco. It was built in 1892 (we
think), mostly redwood, and originally had gas lighting, then horrible
knob-and-tube wiring, then conduit (that was mandatory for a time,
still is for commercial buildings), finally Romex. I cleaned it up a
lot.
We now live in a new house, built in 1992. It's amazing: everything
works, and there's 15 amps at every outlet. All I had to do was put in
some dimmers. The street wiring is underground, but much of the city
still has overhead wiring with the occasional "pole pig" (stepdown
transformer) up on the poles, too. They're gradually undergrounding
everything, but it's very expensive and may take decades to complete.
They are just now tearing up my street to replace all the old gas
lines with high-pressure (75 psi) plastic tubes, which they can push
inside of the old rusty low-pressure pipes.
Here in California, houses are almost always made of wood over a
concrete foundation. That combination handles earthquakes very well.
Where are you? What's the house made of? I've seen lots of stone in
the UK. Quaint, as long as the ground doesn't shake.
It's interesting to compare wiring in the US to the UK. We have
one-way runs of 120 volts, wire-nut junctions, push-in-wiring outlets,
plastic junction boxes, small plugs, GFDs only in wet areas. You have
(I think) ring-wired 240, screw terminal blocks, master GFDs, huge
plugs with fuses inside.
John
I've just bought and moved into a 100 (thereabouts) year old house in
Auckland, made of mainly kauri (local hardwood no longer readily
obtainable). Fortunate that - the crappy 'remedial' works done on
drainage
in this place over the years would have destroyed wood of lesser quality!
Anyway I've just about finished getting the old wiring out - mainly that
conduit-run insulated cabling which has insulation which falls apart long
before now, but also later wiring with PVC-like qualities (except for the
similar rodent-tasty, crumbly nature of it). Here it's all 240V off the
pole
(like yours, being undergrounded, but they haven't even started in this
older area yet) or 3-phase 415V if required. No fuses in plugs but GFD's
are
now mandatory in new installations at the fusebox - I've got several in
mine
so I won't lose everything at once.
Do fusebox GFD's false-trip a lot? We have them in outlets in the
kitchen, bathrooms, and garage, anywhere potentially wet, and certain
brush-motor-type appliances tend to trip them; slows me down grinding
coffee sometimes. Sometimes they just trip, probably from transients
somewhere.
I measured 5 megs leakage on my garbage disposal, and that was enough
to trip a GFD. I also had a sump pump (the lower level of my house is
below the street, so we have to pump stuff up from the lower bathroom)
that tripped its GFD from a tiny bit of leakage.
John
I've guessed that your expression 'GFD' is the same as whatever we use |
(can't recall name - brain's on holiday today) - false tripping is extremely
rare in my experience (with the more modern devices anyway). But it also
depends on what you're powering. My wife does glass casting and has a cute
mixture of power tools and water in her workshop. The only thing that's ever
tripped the protection device was a *very* wet multi-outlet power board.
Fair enough too, in my opinion! :-)
Ken |
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John Larkin
Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: 110V ac |
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On Sat, 12 Feb 2005 04:20:23 +0000, Pooh Bear
<rabbitsfriendsandrelations@hotmail.com> wrote:
| Quote: |
I don't know what 'knob and tube ' wiring is - do you have a link or something ?
|
Single once-upon-a-time-insulated wires, about a foot apart. They go
through studs and rafters through drilled holes with ceramic tubes
inserted, and can angle off a sort of stack of two ceramic cylinders
with a nail through the middle. Joints are twisted and taped; no
junction boxes. Fire waiting to happen.
http://www.oldhouseweb.com/stories/Detailed/10327.shtml
| Quote: | Here in California, houses are almost always made of wood over a
concrete foundation. That combination handles earthquakes very well.
Sensible move, although I seem to recall a number of Victorian style houses
collapsing during the San Francisco ? quake of when ? several decades back ?
Foundations in that area maybe not up to it ?
|
The Big One was 1906; 9.0 roughly. Half the city was destroyed, a few
thousand killed. There's a wonderful Irish pub near work that has a
clock stopped at 5:15 (AM) which they swear fell and broke in the 06
quake. Guiness, Harp, and Widmer on tap, free popcorn, so we accept
the story.
The Pretty Big One was 1989, 7.2, about 80 killed. A few apartment
buildings in the Marina neighborhood collapsed, a combination of weak
ground floors (garages) and soil liquefaction (built on bay fill from
an old World's Fair.) But the deaths were from a freeway collapse and
brick buildings. The 89 quake took out two brick chimneys in my old
Victorian, leaving holes in the ceiling, now skylights. Our new house
has a massive reinforced concrete foundation, shear walls galore, and
steel structures in the front and back where it's weakest from the
garage door and windows and stuff.
| Quote: |
Where are you?
St Albans - about 20 mi N of London. City history dates back to Roman times when it
was called Verulamium.
Just far enough out of London to get away from the mad city thing but conveniently
placed to visit when you want to indulge.
|
We love London, especially the north part, Hampstead Heath and all
that. But then, I don't know too much about the rest. Spent some time
in Oxford last spring... very nice. It did scare me, though,
earthquake-wise; it'll be a pile of Oxford-shaped rocks if anything
happens.
John
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Pooh Bear
Guest
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| Posted:
Sat Feb 12, 2005 6:11 am Post subject:
Re: 110V ac |
|
|
John Larkin wrote:
| Quote: | On Fri, 11 Feb 2005 05:58:01 +0000, Pooh Bear
rabbitsfriendsandrelations@hotmail.com> wrote:
John Larkin wrote:
Here we have residential 120-0-120 power. In my old house, a 100+
year-old Victorian, we had an intermittent open neutral (that's the 0v
line in the middle) out on the pole outside. That caused interesting
effects, as about half the 120-volt devices in the house were then
operating in series with the other half, off 240 volts.
That sounds entertaining !
How common is 'power off the pole' in the US ?
We only see it here in the UK in remote rural areas.
Incidentally, your house must be around the same age as mine - 113 yrs old here.
Whereabouts is that ?
Holly Park neighborhood of San Francisco. It was built in 1892 (we
think), mostly redwood, and originally had gas lighting, then horrible
knob-and-tube wiring, then conduit (that was mandatory for a time,
still is for commercial buildings), finally Romex. I cleaned it up a
lot.
|
Same build date here. Evidence of former gas lighting too.
I have no idea when electricity was added but there a few remnants of old rubber
insulated wiring if you look around under the floorboards. Amazingly, last time I
looked, the rubber was still unperished !
I don't know what 'knob and tube ' wiring is - do you have a link or something ?
| Quote: | We now live in a new house, built in 1992. It's amazing: everything
works, and there's 15 amps at every outlet. All I had to do was put in
some dimmers. The street wiring is underground, but much of the city
still has overhead wiring with the occasional "pole pig" (stepdown
transformer) up on the poles, too. They're gradually undergrounding
everything, but it's very expensive and may take decades to complete.
|
In towns / cities here - overhead mains wiring is unknown. I do still have an
overhead telephone line from a pole though and a second underground one from a cable
company - just for diversity :-).
| Quote: | They are just now tearing up my street to replace all the old gas
lines with high-pressure (75 psi) plastic tubes, which they can push
inside of the old rusty low-pressure pipes.
|
Ah yes - popular tactic is to push modern plastic pipes inside the old stuff here
too. I think they may be doing that with water now too. The infrastructure is getting
old.
| Quote: | Here in California, houses are almost always made of wood over a
concrete foundation. That combination handles earthquakes very well.
|
Sensible move, although I seem to recall a number of Victorian style houses
collapsing during the San Francisco ? quake of when ? several decades back ?
Foundations in that area maybe not up to it ?
St Albans - about 20 mi N of London. City history dates back to Roman times when it
was called Verulamium.
Just far enough out of London to get away from the mad city thing but conveniently
placed to visit when you want to indulge.
| Quote: | What's the house made of?
|
Classic brick built. Very typical of Victorian houses. One of the end houses of a
terrace of four.
| Quote: | I've seen lots of stone in the UK. Quaint, as long as the ground doesn't shake.
|
Not much stone round here generally. Aside from the cathedral. Even that is something
of a mixture of styles and build materials since it dates from Norman times.
| Quote: | It's interesting to compare wiring in the US to the UK. We have
one-way runs of 120 volts, wire-nut junctions, push-in-wiring outlets,
plastic junction boxes, small plugs, GFDs only in wet areas. You have
(I think) ring-wired 240, screw terminal blocks, master GFDs, huge
plugs with fuses inside.
|
Ring wiring is a neat idea, although for reasons related to its former role as a
rented accomadation, my property actually has 4 x 30 A spurs ( plus lighting circuits
of course ). The ancient 'panel' hasn't a breaker in sight but arrays of good old
fashioned fuses - some of which are replaceable wire link types !
That idea of fusing the plugs never caught on worldwide. And yes - they're pretty
robust too. From pics I've seen it looks like Iraq adopted our system, as a curious
sidenote.
Cheers, Graham |
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Dan Mills
Guest
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| Posted:
Sat Feb 12, 2005 7:43 am Post subject:
Re: 110V ac |
|
|
John Woodgate wrote:
| Quote: | It sounds as though you have voltage-sensing devices. In Europe we now
have differential current-sensing devices - Residual Current Circuit
Breakers - with controlled operating currents, such as 10 mA and 30 mA.
The latter are normally used, ad protect very well against life-
endangering shock while minimising nuisance tripping.
|
IIRC the American GFI is a 5mA sensitivity device! Talk about a world of
pain!
Modern UK practice is to use a 'split load' consumer unit with the lighting
circuits connected before the RCD (possibly also any dedicated circuit for
a fridge or freezer), with most of the sockets connected to the RCD
protected side.
However RCDs are only REQUIRED where circuits are likely to be used outdoors
or where other special hazards exist. Everywhere else they are optional
(but strongly recommended).
My setup uses combined RCD/overload trips (known as RCBOs) rather then a
split load system because I did not want all the sockets failing due to a
fault in one room. The incoming supply is also fed thru a 100mA time delay
RCD for fire protection.
Regards, Dan. |
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Ken Taylor
Guest
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| Posted:
Sat Feb 12, 2005 2:57 pm Post subject:
Re: 110V ac |
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"John Larkin" <jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX> wrote in
message news:dk2r015v4le8akn88bf025na1f9iko2far@4ax.com...
| Quote: | On Sat, 12 Feb 2005 04:20:23 +0000, Pooh Bear
rabbitsfriendsandrelations@hotmail.com> wrote:
I don't know what 'knob and tube ' wiring is - do you have a link or
something ?
Single once-upon-a-time-insulated wires, about a foot apart. They go
through studs and rafters through drilled holes with ceramic tubes
inserted, and can angle off a sort of stack of two ceramic cylinders
with a nail through the middle. Joints are twisted and taped; no
junction boxes. Fire waiting to happen.
http://www.oldhouseweb.com/stories/Detailed/10327.shtml
Here in California, houses are almost always made of wood over a
concrete foundation. That combination handles earthquakes very well.
Sensible move, although I seem to recall a number of Victorian style
houses
collapsing during the San Francisco ? quake of when ? several decades
back ?
Foundations in that area maybe not up to it ?
The Big One was 1906; 9.0 roughly. Half the city was destroyed, a few
thousand killed. There's a wonderful Irish pub near work that has a
clock stopped at 5:15 (AM) which they swear fell and broke in the 06
quake. Guiness, Harp, and Widmer on tap, free popcorn, so we accept
the story.
The Pretty Big One was 1989, 7.2, about 80 killed. A few apartment
buildings in the Marina neighborhood collapsed, a combination of weak
ground floors (garages) and soil liquefaction (built on bay fill from
an old World's Fair.) But the deaths were from a freeway collapse and
brick buildings. The 89 quake took out two brick chimneys in my old
Victorian, leaving holes in the ceiling, now skylights. Our new house
has a massive reinforced concrete foundation, shear walls galore, and
steel structures in the front and back where it's weakest from the
garage door and windows and stuff.
Where are you?
St Albans - about 20 mi N of London. City history dates back to Roman
times when it
was called Verulamium.
Just far enough out of London to get away from the mad city thing but
conveniently
placed to visit when you want to indulge.
We love London, especially the north part, Hampstead Heath and all
that. But then, I don't know too much about the rest. Spent some time
in Oxford last spring... very nice. It did scare me, though,
earthquake-wise; it'll be a pile of Oxford-shaped rocks if anything
happens.
John
New Zealand is known as the 'Shaky Isles' because it's so earthquake zone. |
Wellington (the capital) is on a fault line - you can see the fault line in
the hills as you drive along the motorway into the city. There are buildings
which straddle it too! Auckland (where I am) isn't so quake-prone, though it
is built within the confines of seven (mainly dormant) volcanoes.....
Ken |
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John Larkin
Guest
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| Posted:
Sun Feb 13, 2005 1:10 am Post subject:
Re: 110V ac |
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On Fri, 11 Feb 2005 21:45:42 +0000, John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:
| Quote: | I read in sci.electronics.design that John Larkin <jjlarkin@highSNIPland
THIStechPLEASEnology.com> wrote (in <gt6q0194pak21vuu69529hkk6pbd0de5sd@
4ax.com>) about '110V ac', on Fri, 11 Feb 2005:
Do fusebox GFD's false-trip a lot? We have them in outlets in the
kitchen, bathrooms, and garage, anywhere potentially wet, and certain
brush-motor-type appliances tend to trip them; slows me down grinding
coffee sometimes. Sometimes they just trip, probably from transients
somewhere.
I measured 5 megs leakage on my garbage disposal, and that was enough to
trip a GFD. I also had a sump pump (the lower level of my house is below
the street, so we have to pump stuff up from the lower bathroom) that
tripped its GFD from a tiny bit of leakage.
It sounds as though you have voltage-sensing devices. In Europe we now
have differential current-sensing devices - Residual Current Circuit
Breakers - with controlled operating currents, such as 10 mA and 30 mA.
The latter are normally used, ad protect very well against life-
endangering shock while minimising nuisance tripping.
|
How could a GFD be a voltage sensing device? What voltage would it
sense? Every one I ever heard of was a common-mode current
transformer.
John |
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Rich Grise
Guest
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| Posted:
Sun Feb 13, 2005 1:34 pm Post subject:
Re: 110V ac |
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On Thu, 10 Feb 2005 23:16:55 -0800, John Larkin wrote:
| Quote: | Here in California, houses are almost always made of wood over a
concrete foundation. That combination handles earthquakes very well.
|
Mudslides, however, sometimes not so well. )-;
http://news.google.com/news?q=%22anaheim+hills%22&btnG=Search+News
Cheers!
Rich |
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John Larkin
Guest
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| Posted:
Mon Feb 14, 2005 1:00 am Post subject:
Re: 110V ac |
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On Sun, 13 Feb 2005 07:34:49 GMT, Rich Grise <richgrise@example.net>
wrote:
No reasonable construction can stand up to a mudslide, any more than a
lava flow. Envision a million tons of nearly solid earth and rock
coming down a hill at 60 MPH. The sensible thing to do is not live in
a slide-prone place.
John |
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Rich Grise
Guest
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| Posted:
Mon Feb 14, 2005 6:10 am Post subject:
Re: 110V ac |
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On Sun, 13 Feb 2005 11:00:06 -0800, John Larkin wrote:
| Quote: | On Sun, 13 Feb 2005 07:34:49 GMT, Rich Grise <richgrise@example.net
wrote:
On Thu, 10 Feb 2005 23:16:55 -0800, John Larkin wrote:
Here in California, houses are almost always made of wood over a
concrete foundation. That combination handles earthquakes very well.
Mudslides, however, sometimes not so well. )-;
http://news.google.com/news?q=%22anaheim+hills%22&btnG=Search+News
Cheers!
Rich
No reasonable construction can stand up to a mudslide, any more than a
lava flow. Envision a million tons of nearly solid earth and rock
coming down a hill at 60 MPH. The sensible thing to do is not live in
a slide-prone place.
|
Makes me want to ask the Anaslime Hills denizens, "If you're so rich,
Howcome you're not smart?"
;-)
Cheers!
Rich |
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