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Default AFCI test rig and test design

I just received my AFCI 20A duplex outlet and downstream OBC protector:

Leviton AFTR2-GY SmartlockPro
Outlet Branch Circuit Arc-Fault Circuit Interrupter Receptacle,
20-Amp, 120-volt, Grey

At first I was miffed about not noticing it was grey-colored, but then I
decided it would be useful to know which outlet were AFCI "master" outlets
at a glance.

I took a 14AWG three-wire cord and plug from an old A/C unit and wired it to
the outlet which I installed into a plastic duplex outlet box. Now,
anything plugged into the outlet would be arc-fault protected. But I soon
realized that to test the protection of outlets that would be downstream, I
needed to connect outlets to the LOAD terminals of the AFCI. So I took an
outlet strip that had a broken plug, cut that off and attached the cord to
the LOAD terminals inside the plastic box. Now, anything that generated an
arc plugged into either the duplex outlet or the outlet strip (no surge
protection - just six outlets and a switch/circuit breaker).

The next phase is to figure out some testing parameters and arc-testing
situations. For the test item, I thought I'd use an old plastic hairdryer
that can pull 1500 watts and that has a pretty sparky motor. Same for a 70
year old Black and Decker 1/2" drill (I'll have to take pictures - they just
don't make things like they used to) that has a notorious spark.

I will also test those items and a 1500 watt space heater with old, corroded
extension cords and outlets that have been replaced for "cause" in the past.
(There *is* a reason to save dead stuff!). As Bud pointed out, the AFCI's
need a fairly large "base" current (5A) to respond to an arc fault. I
believe all three test items qualify. I am not sure I am going to create a
carbon arc - only because I can't seem to find my stash of carbon rods at
the moment. I might try to arc some pencil leads but that would have very
low SAF.

I also want to test the rig I've built with GFCI's. To that end, I will use
my push button GFCI tester both with the AFCI plugged into a GFCI outlet and
a GFCI outlet plugged into the AFCI test rig.

From looking around it seems that cost-wise, GFCI breakers with AFCI outlets
in the cheapest way to go. I can't figure out why the AFCI outlets are
cheaper than the breakers, but that seems to be the case. My best guess is
the size factor - they have to "shrink" the AFCI components to get them to
fit into a breaker slot.

The outlet itself is a little larger than a GFCI but seems much heavier -
will try to remember to weigh them. It has a bump on the back that would
make it a tight fit for passthrough use. The unit comes with double screw
clamps that are sort of like a back-stab outlet, but the wire is inserted
under a screw down brass clamp (no hook needs to be formed as with some
screw terminals so that's one less point of probable failure). The unit
ships with the reset button tripped as a precaution.

The outlet is quite stiff - it comes with a child-proof sliding shutter on
the hot slot and has a T-shaped neutral hole to accept 5-20P NEMA plugs
(IIRC). Not sure if that means the outlet's going to hold plugs more
securely or if the added force needed to insert the plug is going to result
in - you guessed it - partially inserted plugs and potential arcing.

Any ideas about what other tests I might perform are welcome. I'm just not
comfortable relying on an on board "Test Button" to determine whether the
AFCI is still protecting against arc faults. I'd like to be able to come up
with some test rig or procedure that will simulate real-world arcing
conditions.

--
Bobby G.


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Default AFCI test rig and test design

"Robert Green" wrote:
I just received my AFCI 20A duplex outlet and downstream OBC protector:

Leviton AFTR2-GY SmartlockPro
Outlet Branch Circuit Arc-Fault Circuit Interrupter Receptacle,
20-Amp, 120-volt, Grey

At first I was miffed about not noticing it was grey-colored, but then I
decided it would be useful to know which outlet were AFCI "master" outlets
at a glance.

I took a 14AWG three-wire cord and plug from an old A/C unit and wired it to
the outlet which I installed into a plastic duplex outlet box. Now,
anything plugged into the outlet would be arc-fault protected. But I soon
realized that to test the protection of outlets that would be downstream, I
needed to connect outlets to the LOAD terminals of the AFCI. So I took an
outlet strip that had a broken plug, cut that off and attached the cord to
the LOAD terminals inside the plastic box. Now, anything that generated an
arc plugged into either the duplex outlet or the outlet strip (no surge
protection - just six outlets and a switch/circuit breaker).

The next phase is to figure out some testing parameters and arc-testing
situations. For the test item, I thought I'd use an old plastic hairdryer
that can pull 1500 watts and that has a pretty sparky motor. Same for a 70
year old Black and Decker 1/2" drill (I'll have to take pictures - they just
don't make things like they used to) that has a notorious spark.

I will also test those items and a 1500 watt space heater with old, corroded
extension cords and outlets that have been replaced for "cause" in the past.
(There *is* a reason to save dead stuff!). As Bud pointed out, the AFCI's
need a fairly large "base" current (5A) to respond to an arc fault. I
believe all three test items qualify. I am not sure I am going to create a
carbon arc - only because I can't seem to find my stash of carbon rods at
the moment. I might try to arc some pencil leads but that would have very
low SAF.

I also want to test the rig I've built with GFCI's. To that end, I will use
my push button GFCI tester both with the AFCI plugged into a GFCI outlet and
a GFCI outlet plugged into the AFCI test rig.

From looking around it seems that cost-wise, GFCI breakers with AFCI outlets
in the cheapest way to go. I can't figure out why the AFCI outlets are
cheaper than the breakers, but that seems to be the case. My best guess is
the size factor - they have to "shrink" the AFCI components to get them to
fit into a breaker slot.

The outlet itself is a little larger than a GFCI but seems much heavier -
will try to remember to weigh them. It has a bump on the back that would
make it a tight fit for passthrough use. The unit comes with double screw
clamps that are sort of like a back-stab outlet, but the wire is inserted
under a screw down brass clamp (no hook needs to be formed as with some
screw terminals so that's one less point of probable failure). The unit
ships with the reset button tripped as a precaution.

The outlet is quite stiff - it comes with a child-proof sliding shutter on
the hot slot and has a T-shaped neutral hole to accept 5-20P NEMA plugs
(IIRC). Not sure if that means the outlet's going to hold plugs more
securely or if the added force needed to insert the plug is going to result
in - you guessed it - partially inserted plugs and potential arcing.

Any ideas about what other tests I might perform are welcome. I'm just not
comfortable relying on an on board "Test Button" to determine whether the
AFCI is still protecting against arc faults. I'd like to be able to come up
with some test rig or procedure that will simulate real-world arcing
conditions.

--
Bobby G.


For some reason, I always like to arc the light switches. You put a load
across a light switch, then very slowly make or break the connection. You
can usually hear the buzz. Everyone has done that, right ?

Greg
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"gregz" wrote in message
...
"Robert Green" wrote:


stuff snipped

Any ideas about what other tests I might perform are welcome. I'm just

not
comfortable relying on an on board "Test Button" to determine whether

the
AFCI is still protecting against arc faults.


For some reason, I always like to arc the light switches. You put a load
across a light switch, then very slowly make or break the connection. You
can usually hear the buzz. Everyone has done that, right ?


Not me! That's a good one. I hadn't thought about wiring in the lighting
circuits to protect against arc faults but you bring up a good point and
another item to add to my checklist. I probably should break the AFCI
outlet out of the single gang box and wire it into a duplex box test rig
with a light switch I can "jigger" to create an arc.

I seem to recall at least a few of the switches I have are "snap" switches
specifically designed to resist arcing. I'm sure I have something that will
work in the "box of the undead" electrical equipment. I even have some
switches going back to the to the two black cylinders stacked like
stoplights where when you push the lower one in, the upper one pops out. I
assume they're from 1940 or so because they were in the box I inherited from
my junk saving father. (-:

Thanks for your input, Greg.

--
Bobby G.


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On 7/16/2013 2:34 PM, Robert Green wrote:

I am not sure I am going to create a
carbon arc - only because I can't seem to find my stash of carbon rods at
the moment. I might try to arc some pencil leads but that would have very
low SAF.


If you use carbon rods or some similar arc I suggest you use something
like the 1500W space heater in series. That limits the current. Else you
can have a current that is the available fault current at the outlet,
which one of the articles said is 60A or higher (if I remember right).

Obviously this is a shock and fire hazard.


From looking around it seems that cost-wise, GFCI breakers with AFCI outlets
in the cheapest way to go.


But that does not necessarily protect the house wiring. The NEC allows
an AFCI receptacle to protect a branch circuit if it is the first
device, and the branch circuit is wired through it, and the wiring to
the panel is something like in metal conduit.

I can't figure out why the AFCI outlets are
cheaper than the breakers, but that seems to be the case. My best guess is
the size factor - they have to "shrink" the AFCI components to get them to
fit into a breaker slot.


If you need an AFCI breaker for a SquareD panel it comes from SquareD
and they can charge more. Receptacles can be made by anyone (although I
don't know of anyone but Leviton that make them now).


The unit
ships with the reset button tripped as a precaution.


You used to be able to reverse-wire (line-load) a GFCI receptacle and
the receptacle would seem to work as expected, but the receptacle is not
GFCI protected (downstream is) and a GFCI trip did not disconnect the
receptacle (but did disconnect downstream).

The UL standard was changed. Now if reverse-wired the receptacle is
still not GFCI protected. But a trip now disconnects the receptacle and
it can't be reset. To protect from reverse- wired installation, the
GFCIs are shipped tripped (and can not be reset).

The AFCI receptacle includes ground fault protection, and I suspect the
same applies.


The outlet is quite stiff - it comes with a child-proof sliding shutter on
the hot slot ...


Child-proof receptacles are generally required for new construction and
replacement in a residence.

----------------------------------------
A "snap" switch likely has an AC-DC rating. The silent switches are an
AC only rating.
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Default AFCI test rig and test design

On Tuesday, July 16, 2013 4:34:17 PM UTC-4, Robert Green wrote:
I am not sure I am going to create a

carbon arc - only because I can't seem to find my stash of carbon rods at

the moment. I might try to arc some pencil leads but that would have very

low SAF.


I haven't opened one since I was a kid, but a D cell used to have a carbon rod as the positive terminal, about 3/8 inch in diameter, and the lantern battery had one almost an inch across.


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if you want to get a carbon rod out of a cell (a "battery" is multiple cells... yeah I know I'm being a pedant) you want a "heavy duty" cell not an alkaline one.
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Still true, in the case of carbon zinc cells.

Opening carbon zinc batteries makes my
Mom yell at me. The managanese dioxide
makes a mess.
..
Christopher A. Young
Learn more about Jesus
www.lds.org
..
..
"TimR" wrote in message ...

I haven't opened one since I was a kid, but a D cell used to have a carbon rod as the positive terminal, about 3/8 inch in diameter, and the lantern battery had one almost an inch across.

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On Wednesday, July 17, 2013 11:41:37 AM UTC-4, N8N wrote:
if you want to get a carbon rod out of a cell (a "battery" is multiple cells... yeah I know I'm being a pedant) you want a "heavy duty" cell not an alkaline one.


So what's inside an alkaline one?

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"bud--" wrote in message
b.com...
On 7/16/2013 2:34 PM, Robert Green wrote:

I am not sure I am going to create a
carbon arc - only because I can't seem to find my stash of carbon rods

at
the moment. I might try to arc some pencil leads but that would have

very
low SAF.


If you use carbon rods or some similar arc I suggest you use something
like the 1500W space heater in series. That limits the current. Else you
can have a current that is the available fault current at the outlet,
which one of the articles said is 60A or higher (if I remember right).


Thanks. That sounds like an excellent idea. I recall reading that as well.

Obviously this is a shock and fire hazard.


I'm souring on the carbon-arc testing based on what you've pointed out and
how far away it is from real-world faults that are likely to set off the
AFCI.

From looking around it seems that cost-wise, GFCI breakers with AFCI

outlets
in the cheapest way to go.


But that does not necessarily protect the house wiring. The NEC allows
an AFCI receptacle to protect a branch circuit if it is the first
device, and the branch circuit is wired through it, and the wiring to
the panel is something like in metal conduit.


I've only got the NEC updates guide so I am not sure what the codes are. I
assume the reason the feed to the first AFCI receptacle should be in conduit
is so that if an arc does form before reaching the protection device, it's
safely enclosed and not like to spark a fire. The circuits I want to
protect are all new ones I installed to power devices that I didn't want to
run through old, cloth covered wiring runs rated (when new) at 15A. They
are circuits for window ACs, toasters, microwaves, space heaters and the
workbench outlets powering the RAS and other power hungry tools.

I can't figure out why the AFCI outlets are
cheaper than the breakers, but that seems to be the case. My best guess

is
the size factor - they have to "shrink" the AFCI components to get them

to
fit into a breaker slot.


If you need an AFCI breaker for a SquareD panel it comes from SquareD
and they can charge more. Receptacles can be made by anyone (although I
don't know of anyone but Leviton that make them now).


That sort of makes sense. (-: I am reluctant to use AFCI breakers because
of the pigtail issues (the circuit box is crowded enough) and with outlet
AFCIs I can quietly remove them (yes, I know they are fixtures and that's
technically a no-no) and replace them with standard outlets when I move.

Here's another question. What does "Spec Grade" mean on the Leviton AFCI?
Is it just marketing hype?

The unit
ships with the reset button tripped as a precaution.


You used to be able to reverse-wire (line-load) a GFCI receptacle and
the receptacle would seem to work as expected, but the receptacle is not
GFCI protected (downstream is) and a GFCI trip did not disconnect the
receptacle (but did disconnect downstream).

The UL standard was changed. Now if reverse-wired the receptacle is
still not GFCI protected. But a trip now disconnects the receptacle and
it can't be reset. To protect from reverse- wired installation, the
GFCIs are shipped tripped (and can not be reset).


Yes. After I posted that message I did some more reading and Leviton says
what you just did. It's shipped tripped to make sure it's not installed
incorrectly. Good idea but confusing if you expect it to work out of the
box.

The AFCI receptacle includes ground fault protection, and I suspect the
same applies.


Do you know how the plug-in GFCI testers with the pushbutton work? Are they
creating a current mismatch between the two conductors?

The outlet is quite stiff - it comes with a child-proof sliding shutter

on
the hot slot ...


Child-proof receptacles are generally required for new construction and
replacement in a residence.


So it seems. I wasn't kidding when I wrote that ironically, making a plug
tough to insert completely could lead to arcing. Perhaps it's because it's
so new but it's a real chore to insert a three-wire plug into the outlet.
While I have a spring scale that can tell me how much force it takes to
remove a plug from the outlet, I don't know of any way to measure the
insertion force. Perhaps placing the outlet on a bathroom scale and then
noting what the scale reads when the plug is fully inserted would give me a
ballpark figure.

----------------------------------------
A "snap" switch likely has an AC-DC rating. The silent switches are an
AC only rating.


Hmm. Do you know why that is? Is it related to arcing or some other issue?

Thanks for your input, Bud, it's been very helpful. I am sure my wife will
appreciate your "talking" me out of carbon rod arcing tests.

--
Bobby G.


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"TimR" wrote in message news:3a4168e6-a2e1-4eff-8bb0-

stuff snipped

I haven't opened one since I was a kid, but a D cell used to have a carbon

rod as the
positive terminal, about 3/8 inch in diameter, and the lantern battery had

one almost an inch
across.


Oh yes, now that you mention it, that's probably a good source for the
carbon rods. Time to get out the hacksaw just to check. (-: I think I
will skip the carbon arc test for the reasons previously stated but knowing
whether there's still a carbon rod in a D cell is worth investigating.

--
Bobby G.




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"N8N" wrote in message
...
if you want to get a carbon rod out of a cell (a "battery" is multiple

cells... yeah I know I'm being a pedant) you want a "heavy duty" cell not
an alkaline one.

Got both. Didn't realize they had different internals. Thanks!

--
Bobby G.


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On the subject of trhe over and under push-button light switches, those date back to the early 1930's, probably even earlier. My grandparents had them in their 1901-built house in Woodside, Queens, NYC, in the 1940's, and they were old and worn looking even then (both my grandparents and the light switches). The house had been converted from gas lighting to electric by running the electric wires in the old gas pipes in many of the rooms. The house is still there as far as I know, 39-27 56th street.
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On 7/17/2013 2:02 PM, Robert Green wrote:
wrote in message
b.com...
On 7/16/2013 2:34 PM, Robert Green wrote:

I am not sure I am going to create a
carbon arc - only because I can't seem to find my stash of carbon rods

at
the moment. I might try to arc some pencil leads but that would have

very
low SAF.


If you use carbon rods or some similar arc I suggest you use something
like the 1500W space heater in series. That limits the current. Else you
can have a current that is the available fault current at the outlet,
which one of the articles said is 60A or higher (if I remember right).


Thanks. That sounds like an excellent idea. I recall reading that as well.

Obviously this is a shock and fire hazard.


I'm souring on the carbon-arc testing based on what you've pointed out and
how far away it is from real-world faults that are likely to set off the
AFCI.


But think of the fun....


From looking around it seems that cost-wise, GFCI breakers with AFCI

outlets
in the cheapest way to go.


But that does not necessarily protect the house wiring. The NEC allows
an AFCI receptacle to protect a branch circuit if it is the first
device, and the branch circuit is wired through it, and the wiring to
the panel is something like in metal conduit.


I've only got the NEC updates guide so I am not sure what the codes are. I
assume the reason the feed to the first AFCI receptacle should be in conduit
is so that if an arc does form before reaching the protection device, it's
safely enclosed and not like to spark a fire.


Correct. (It is a little broader than just metal conduit, but I am too
lazy to look it up.)

The circuits I want to
protect are all new ones I installed to power devices that I didn't want to
run through old, cloth covered wiring runs rated (when new) at 15A. They
are circuits for window ACs, toasters, microwaves, space heaters and the
workbench outlets powering the RAS and other power hungry tools.


The current NEC generally requires AFCI protection in a house for new
circuits that don't have to be GFCI protected. (And gfretwell recently
wrote that the 2014 NEC adds laundry and [another one] that will have to
be AFCI protected.

I can't figure out why the AFCI outlets are
cheaper than the breakers, but that seems to be the case. My best guess

is
the size factor - they have to "shrink" the AFCI components to get them

to
fit into a breaker slot.


If you need an AFCI breaker for a SquareD panel it comes from SquareD
and they can charge more. Receptacles can be made by anyone (although I
don't know of anyone but Leviton that make them now).


That sort of makes sense. (-: I am reluctant to use AFCI breakers because
of the pigtail issues (the circuit box is crowded enough) and with outlet
AFCIs I can quietly remove them (yes, I know they are fixtures and that's
technically a no-no) and replace them with standard outlets when I move.


They kinda become non-code compliant.

I think my post in a recent thread got into use of AFCI receptacles.

The NEC now wants AFCI protection on most new house circuits and
extensions of existing circuits where the extension is in an area that
requires AFCI protection.


Here's another question. What does "Spec Grade" mean on the Leviton AFCI?
Is it just marketing hype?


You can also get regular receptacles and switches that are "spec grade".
It is a higher quality and should last longer. Might be particularly
good in a kitchen.

The other grade is "consumer" or "builder" (and there may be an
intermediate grade).


Do you know how the plug-in GFCI testers with the pushbutton work? Are they
creating a current mismatch between the two conductors?


The connect a resistor from the hot wire to the ground wire. The
resistor is sized for about 5mA. The current on the hot wire is 5mA
higher than on the neutral. They do not work if there is no ground.

GFCI receptacles and breakers have the same resistor but connected from
the downstream hot to the upstream neutral (or vice versa). The current
on the hot and neutral are about 5mA different. The ground wire is not
used and the test will work on a receptacle without a ground.

A "snap" switch likely has an AC-DC rating. The silent switches are an
AC only rating.


Hmm. Do you know why that is? Is it related to arcing or some other issue?


When switching AC, the zero-crossings help extinguish the arc of the
opening contacts. DC can arc much farther and you want a fast acting
(snap) switch. If a switch has both AC and DC ratings, the DC voltage
rating should be considerably lower than the AC rating.

AC only switches have a motor rating at something like 80% of the normal
rating. Not likely AC-DC switches do.




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"bud--" wrote in message
eb.com...
On 7/17/2013 2:02 PM, Robert Green wrote:
wrote in message
b.com...
On 7/16/2013 2:34 PM, Robert Green wrote:

I am not sure I am going to create a
carbon arc - only because I can't seem to find my stash of carbon rods

at
the moment. I might try to arc some pencil leads but that would have

very
low SAF.

If you use carbon rods or some similar arc I suggest you use something
like the 1500W space heater in series. That limits the current. Else

you
can have a current that is the available fault current at the outlet,
which one of the articles said is 60A or higher (if I remember right).


Thanks. That sounds like an excellent idea. I recall reading that as

well.

Obviously this is a shock and fire hazard.


I'm souring on the carbon-arc testing based on what you've pointed out

and
how far away it is from real-world faults that are likely to set off the
AFCI.


But think of the fun....


(-:

From looking around it seems that cost-wise, GFCI breakers with

AFCI
outlets
in the cheapest way to go.

But that does not necessarily protect the house wiring. The NEC allows
an AFCI receptacle to protect a branch circuit if it is the first
device, and the branch circuit is wired through it, and the wiring to
the panel is something like in metal conduit.


I've only got the NEC updates guide so I am not sure what the codes are.

I
assume the reason the feed to the first AFCI receptacle should be in

conduit
is so that if an arc does form before reaching the protection device,

it's
safely enclosed and not like to spark a fire.


Correct. (It is a little broader than just metal conduit, but I am too
lazy to look it up.)


I'm going to have to content myself with making things marginally safer but
not as safe as they could be. I'd like to have GFCI/AFCI protection on
every circuit but for now only the ones that pose the greatest threat will
get upgraded.

The circuits I want to
protect are all new ones I installed to power devices that I didn't want

to
run through old, cloth covered wiring runs rated (when new) at 15A.

They
are circuits for window ACs, toasters, microwaves, space heaters and the
workbench outlets powering the RAS and other power hungry tools.


The current NEC generally requires AFCI protection in a house for new
circuits that don't have to be GFCI protected. (And gfretwell recently
wrote that the 2014 NEC adds laundry and [another one] that will have to
be AFCI protected.

I can't figure out why the AFCI outlets are
cheaper than the breakers, but that seems to be the case. My best

guess
is
the size factor - they have to "shrink" the AFCI components to get

them
to
fit into a breaker slot.

If you need an AFCI breaker for a SquareD panel it comes from SquareD
and they can charge more. Receptacles can be made by anyone (although I
don't know of anyone but Leviton that make them now).


That sort of makes sense. (-: I am reluctant to use AFCI breakers

because
of the pigtail issues (the circuit box is crowded enough) and with

outlet
AFCIs I can quietly remove them (yes, I know they are fixtures and

that's
technically a no-no) and replace them with standard outlets when I move.


They kinda become non-code compliant.

I think my post in a recent thread got into use of AFCI receptacles.

The NEC now wants AFCI protection on most new house circuits and
extensions of existing circuits where the extension is in an area that
requires AFCI protection.


It makes sense. I just wish a complete upgrade wasn't a job of titanic
proportions.


Here's another question. What does "Spec Grade" mean on the Leviton

AFCI?
Is it just marketing hype?


You can also get regular receptacles and switches that are "spec grade".
It is a higher quality and should last longer. Might be particularly
good in a kitchen.

The other grade is "consumer" or "builder" (and there may be an
intermediate grade).


Do you know how the plug-in GFCI testers with the pushbutton work? Are

they
creating a current mismatch between the two conductors?


The connect a resistor from the hot wire to the ground wire. The
resistor is sized for about 5mA. The current on the hot wire is 5mA
higher than on the neutral. They do not work if there is no ground.


I didn't realize they need a ground to operate correctly. I should have
saved the manual.

GFCI receptacles and breakers have the same resistor but connected from
the downstream hot to the upstream neutral (or vice versa). The current
on the hot and neutral are about 5mA different. The ground wire is not
used and the test will work on a receptacle without a ground.


You answered my next question before I asked it!

A "snap" switch likely has an AC-DC rating. The silent switches are an
AC only rating.


Hmm. Do you know why that is? Is it related to arcing or some other

issue?

When switching AC, the zero-crossings help extinguish the arc of the
opening contacts. DC can arc much farther and you want a fast acting
(snap) switch. If a switch has both AC and DC ratings, the DC voltage
rating should be considerably lower than the AC rating.

AC only switches have a motor rating at something like 80% of the normal
rating. Not likely AC-DC switches do.


I see. I had noticed the disparity in switch ratings before but had no idea
until now why they should be rated differently. Thanks for the edumacashun.

--
Bobby G.



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On the subject of trhe over and under push-button light switches, those
date back to the early 1930's, probably even earlier. My grandparents had
them in their 1901-built house in Woodside, Queens, NYC, in the 1940's, and
they were old and worn looking even then (both my grandparents and the light
switches). The house had been converted from gas lighting to electric by
running the electric wires in the old gas pipes in many of the rooms. The
house is still there as far as I know, 39-27 56th street.

These switches came from a house in Brooklyn, NY of about the same vintage.
One button is white (for on) the other is black (for off). They still work,
too.

Same deal for gas lights converted to electrical lights. Heated by coal
until the 40's, IIRC.

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Bobby G.




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I'd bet those old switches would arc, as I don't think they had a snap-action mechanism, more like a knife-switch opening and closing.
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I'd bet those old switches would arc, as I don't think they had a

snap-action mechanism, more like a knife-switch opening and closing.

That's a good idea - I have some old porcelain-base knife switches that I
can use to create an arc.

--
Bobby G.


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