On Tue, 10 Dec 2013 19:12:05 -0500, wrote:

The timer uses the line through the load to operate it's clock because it has no neutral. If the load is missing or not enough the clock doesn't work properly. 5 watts is plenty of load for a scr or triac.

Hmm,
So, I = P/E 5/120~~ 42 mA. Not much of a current.

That's a lot of current for some simple electronics.

If there is no neutral Is it open circuit?

No, the return is through the light bulb.

I don't get it. (switch)(load) where does this line end up?

(hot)black wire(switch)blackwire(load)whitewire(r eturn)

No neutral?

It's on the other side of the load. There is always current through
the load. When changing light bulbs, be careful with these because
the lamp is still energized with it turned off.

The Honeywell PLS550A has a little "safety switch" just under the main
button that can be pulled out with a fingernail to cut power to the
switch (and load) when changing a light bulb. See this image:

http://www.honeywellstore.com/store/...imer-white.htm

This page has the spec sheet / instruction manual / user guide:

http://www.aubetech.com/products/pro...166&noLangue=2

The text under the safety switch says:

"Safety Switch: Before replacing a light bulb, pull out to disconnect
power to the switch. This prevents, while the bulb is out, any possible
short circuit which will damage the switch. Push back in after the light
bulb is replaced."

I'm not sure whether the "safety" is for the switch or for the user.
What would happen if I inadvertantly touched the two leads in the light
socket with the switch in the "off" position? Could I feel the current?

I had the predecessor (Ti034), which did not have the safety switch. I
changed the bulb a few times and never had a problem.

Jennifer Murphy wrote:
On Tue, 10 Dec 2013 19:12:05 -0500, wrote:

The timer uses the line through the load to operate it's clock because it has no neutral. If the load is missing or not enough the clock doesn't work properly. 5 watts is plenty of load for a scr or triac.

Hmm,
So, I = P/E 5/120~~ 42 mA. Not much of a current.

That's a lot of current for some simple electronics.

If there is no neutral Is it open circuit?

No, the return is through the light bulb.

I don't get it. (switch)(load) where does this line end up?

(hot)black wire(switch)blackwire(load)whitewire(r eturn)

No neutral?

It's on the other side of the load. There is always current through
the load. When changing light bulbs, be careful with these because
the lamp is still energized with it turned off.

Why and who said there is no return, Eh? Yes, it is hot when turned off.

The Honeywell PLS550A has a little "safety switch" just under the main
button that can be pulled out with a fingernail to cut power to the
switch (and load) when changing a light bulb. See this image:

http://www.honeywellstore.com/store/...imer-white.htm



This page has the spec sheet / instruction manual / user guide:

http://www.aubetech.com/products/pro...166&noLangue=2

The text under the safety switch says:

"Safety Switch: Before replacing a light bulb, pull out to disconnect
power to the switch. This prevents, while the bulb is out, any possible
short circuit which will damage the switch. Push back in after the light
bulb is replaced."

I'm not sure whether the "safety" is for the switch or for the user.
What would happen if I inadvertantly touched the two leads in the light
socket with the switch in the "off" position? Could I feel the current?

I had the predecessor (Ti034), which did not have the safety switch. I
changed the bulb a few times and never had a problem.

The safety switch is to totaly disconnect the load from the switch. It is
for the person doing work on the wiring after the switch. It is not for the
protection of the switch, but could protect the switch if the wires were
shorted to each other on the load side.

As mentioned before the operation of the switch depends on a small ammount
of current passing through the switch. Not enough to ammount to anything
cost wise, but enough to give you a shock.

For just replacing a light bulb, that is not a problem, just don't sick your
finger in the socket.


"Jennifer Murphy"
wrote in message
news
On Tue, 10 Dec 2013 19:12:05 -0500, wrote:

The timer uses the line through the load to operate it's clock because
it has no neutral. If the load is missing or not enough the clock
doesn't work properly. 5 watts is plenty of load for a scr or triac.

Hmm,
So, I = P/E 5/120~~ 42 mA. Not much of a current.

That's a lot of current for some simple electronics.

If there is no neutral Is it open circuit?

No, the return is through the light bulb.

I don't get it. (switch)(load) where does this line end up?

(hot)black wire(switch)blackwire(load)whitewire(r eturn)

No neutral?

It's on the other side of the load. There is always current through
the load. When changing light bulbs, be careful with these because
the lamp is still energized with it turned off.

The Honeywell PLS550A has a little "safety switch" just under the main
button that can be pulled out with a fingernail to cut power to the
switch (and load) when changing a light bulb. See this image:

http://www.honeywellstore.com/store/...imer-white.htm

This page has the spec sheet / instruction manual / user guide:

http://www.aubetech.com/products/pro...166&noLangue=2

The text under the safety switch says:

"Safety Switch: Before replacing a light bulb, pull out to disconnect
power to the switch. This prevents, while the bulb is out, any possible
short circuit which will damage the switch. Push back in after the light
bulb is replaced."

I'm not sure whether the "safety" is for the switch or for the user.
What would happen if I inadvertantly touched the two leads in the light
socket with the switch in the "off" position? Could I feel the current?

I had the predecessor (Ti034), which did not have the safety switch. I
changed the bulb a few times and never had a problem.

On Wed, 11 Dec 2013 05:13:50 -0800, Jennifer Murphy
wrote:

On Tue, 10 Dec 2013 19:12:05 -0500, wrote:

The timer uses the line through the load to operate it's clock because it has no neutral. If the load is missing or not enough the clock doesn't work properly. 5 watts is plenty of load for a scr or triac.

Hmm,
So, I = P/E 5/120~~ 42 mA. Not much of a current.

That's a lot of current for some simple electronics.

If there is no neutral Is it open circuit?

No, the return is through the light bulb.

I don't get it. (switch)(load) where does this line end up?

(hot)black wire(switch)blackwire(load)whitewire(r eturn)

No neutral?

It's on the other side of the load. There is always current through
the load. When changing light bulbs, be careful with these because
the lamp is still energized with it turned off.

The Honeywell PLS550A has a little "safety switch" just under the main
button that can be pulled out with a fingernail to cut power to the
switch (and load) when changing a light bulb. See this image:

http://www.honeywellstore.com/store/...imer-white.htm

This page has the spec sheet / instruction manual / user guide:

http://www.aubetech.com/products/pro...166&noLangue=2

The text under the safety switch says:

"Safety Switch: Before replacing a light bulb, pull out to disconnect
power to the switch. This prevents, while the bulb is out, any possible
short circuit which will damage the switch. Push back in after the light
bulb is replaced."

I'm not sure whether the "safety" is for the switch or for the user.
What would happen if I inadvertantly touched the two leads in the light
socket with the switch in the "off" position? Could I feel the current?

I had the predecessor (Ti034), which did not have the safety switch. I
changed the bulb a few times and never had a problem.

Yep. "Be careful".

X10 switches have a slide switch under the button for this.

wrote:
On Wed, 11 Dec 2013 05:13:50 -0800, Jennifer Murphy
wrote:

On Tue, 10 Dec 2013 19:12:05 -0500, wrote:

The timer uses the line through the load to operate it's clock because it has no neutral. If the load is missing or not enough the clock doesn't work properly. 5 watts is plenty of load for a scr or triac.

Hmm,
So, I = P/E 5/120~~ 42 mA. Not much of a current.

That's a lot of current for some simple electronics.

Really on a discrete legacy component in 120V AC circuit?
Yes if we're talking about IC type component.

If there is no neutral Is it open circuit?

No, the return is through the light bulb.

I don't get it. (switch)(load) where does this line end up?

(hot)black wire(switch)blackwire(load)whitewire(r eturn)

No neutral?

It's on the other side of the load. There is always current through
the load. When changing light bulbs, be careful with these because
the lamp is still energized with it turned off.

The Honeywell PLS550A has a little "safety switch" just under the main
button that can be pulled out with a fingernail to cut power to the
switch (and load) when changing a light bulb. See this image:

http://www.honeywellstore.com/store/...imer-white.htm

This page has the spec sheet / instruction manual / user guide:

http://www.aubetech.com/products/pro...166&noLangue=2

The text under the safety switch says:

"Safety Switch: Before replacing a light bulb, pull out to disconnect
power to the switch. This prevents, while the bulb is out, any possible
short circuit which will damage the switch. Push back in after the light
bulb is replaced."

I'm not sure whether the "safety" is for the switch or for the user.
What would happen if I inadvertantly touched the two leads in the light
socket with the switch in the "off" position? Could I feel the current?

I had the predecessor (Ti034), which did not have the safety switch. I
changed the bulb a few times and never had a problem.

Yep. "Be careful".

X10 switches have a slide switch under the button for this.

On Wed, 11 Dec 2013 19:50:46 -0700, Tony Hwang
wrote:

wrote:
On Wed, 11 Dec 2013 05:13:50 -0800, Jennifer Murphy
wrote:

On Tue, 10 Dec 2013 19:12:05 -0500, wrote:

The timer uses the line through the load to operate it's clock because it has no neutral. If the load is missing or not enough the clock doesn't work properly. 5 watts is plenty of load for a scr or triac.

Hmm,
So, I = P/E 5/120~~ 42 mA. Not much of a current.

That's a lot of current for some simple electronics.

Really on a discrete legacy component in 120V AC circuit?

Yes.

Yes if we're talking about IC type component.

What do you think the switch is?

If there is no neutral Is it open circuit?

No, the return is through the light bulb.

I don't get it. (switch)(load) where does this line end up?

(hot)black wire(switch)blackwire(load)whitewire(r eturn)

No neutral?

It's on the other side of the load. There is always current through
the load. When changing light bulbs, be careful with these because
the lamp is still energized with it turned off.

The Honeywell PLS550A has a little "safety switch" just under the main
button that can be pulled out with a fingernail to cut power to the
switch (and load) when changing a light bulb. See this image:

http://www.honeywellstore.com/store/...imer-white.htm

This page has the spec sheet / instruction manual / user guide:

http://www.aubetech.com/products/pro...166&noLangue=2

The text under the safety switch says:

"Safety Switch: Before replacing a light bulb, pull out to disconnect
power to the switch. This prevents, while the bulb is out, any possible
short circuit which will damage the switch. Push back in after the light
bulb is replaced."

I'm not sure whether the "safety" is for the switch or for the user.
What would happen if I inadvertantly touched the two leads in the light
socket with the switch in the "off" position? Could I feel the current?

I had the predecessor (Ti034), which did not have the safety switch. I
changed the bulb a few times and never had a problem.

Yep. "Be careful".

X10 switches have a slide switch under the button for this.

On Tue, 10 Dec 2013 09:54:20 -0800 (PST), "
wrote:

On Tuesday, December 10, 2013 11:30:17 AM UTC-5, Jennifer Murphy wrote:
On Tue, 10 Dec 2013 05:45:31 -0800 (PST), "

wrote:



If the box has no neutral, then there is no code compliant
way to make the switch that requires it work. The issue is
that a programmable switch needs to be powered somehow. That
could be by a battery, through the hot and neutral, or by
using the load circuit. The latter is why the other switch
has a minimum load of 25W. Without some kind of minimal load
for a small current to flow through and power the switch even
when it's off, it would have no power. That small current flows
through the bulb when off and it's enough for thw switch, but
so tiny it won't light the bulb at all.

The minimum it said it needed was actually 40W.

Does the switch really draw 40W for its own use?


No, it draws negligible amount of power. If it drew
40W the box would over heat. It's just that with no
neutral, the switch winds up getting it's power in
series with whatever the load is. With too small of a
load, the switch can't get the necessary voltage/current
that it needs.

I found an old Radio Shack (Microndata) Autoranging DMM. The
programmable switch controls the porch lights, the yard light, and an
outside outlet.

With the switch turned OFF, the DMM shows about .035 volts across the
contacts in the outlet. With the switch ON, it shows about 117 volts.

Then I unplugged the Christmas lights and unscrewed all of the porch
lights. When I unscrewed the last one, the switch went dark. It cannot
operate with an open circuit. It needs at least a small load to work.

What I didn't think to try, was screwing in just one bulb of less than
40 watts to see if it could still work. If I remember, I'll do that when
I take the Christmas light down.

So, it looks like you were right. But then you already knew that. :-)

And, I guess they can continue to teach E=IR in high school physics.

Jennifer Murphy wrote:
On Tue, 10 Dec 2013 09:54:20 -0800 (PST), "
wrote:

On Tuesday, December 10, 2013 11:30:17 AM UTC-5, Jennifer Murphy wrote:
On Tue, 10 Dec 2013 05:45:31 -0800 (PST), "

wrote:



If the box has no neutral, then there is no code compliant
way to make the switch that requires it work. The issue is
that a programmable switch needs to be powered somehow. That
could be by a battery, through the hot and neutral, or by
using the load circuit. The latter is why the other switch
has a minimum load of 25W. Without some kind of minimal load
for a small current to flow through and power the switch even
when it's off, it would have no power. That small current flows
through the bulb when off and it's enough for thw switch, but
so tiny it won't light the bulb at all.

The minimum it said it needed was actually 40W.

Does the switch really draw 40W for its own use?


No, it draws negligible amount of power. If it drew
40W the box would over heat. It's just that with no
neutral, the switch winds up getting it's power in
series with whatever the load is. With too small of a
load, the switch can't get the necessary voltage/current
that it needs.

I found an old Radio Shack (Microndata) Autoranging DMM. The
programmable switch controls the porch lights, the yard light, and an
outside outlet.

With the switch turned OFF, the DMM shows about .035 volts across the
contacts in the outlet. With the switch ON, it shows about 117 volts.

Then I unplugged the Christmas lights and unscrewed all of the porch
lights. When I unscrewed the last one, the switch went dark. It cannot
operate with an open circuit. It needs at least a small load to work.

What I didn't think to try, was screwing in just one bulb of less than
40 watts to see if it could still work. If I remember, I'll do that when
I take the Christmas light down.

So, it looks like you were right. But then you already knew that. :-)

And, I guess they can continue to teach E=IR in high school physics.

Hi,
Nothing wrong with E=IR. You have to expand it to accommodate solid
state devices, Also DMM is highly sensitive due to high input impedance.
If you measure the voltage with analog meter, reading probably is
negligible. Lot of modern devices have phanotom current flowing all the
time. TV, stereos, desk top PCs, etc. what have you are on stand-by. TV
won't come on if you unplug the set when you push remote button.....