Energy Saving Bulbs & Time Switches.
 

I read on the back of a box of Energy Saving Bulbs, that they are not
suitable for use with 'timing devices'.

I've got a couple of table lamps that are on for about five hours a
day, triggered by time switches.

What would be the consequence of using Energy Saving Bulbs in these
table lamps?

Thanks...!

What would be the consequence of using Energy Saving Bulbs in these
table lamps?

It depends on the timing device. These usually work in two different ways.

The more expensive types and those with higher ratings use an
electromechanical switch called a relay. These can switch most types of
load, although whilst switching slightly reactive loads such as energy
saving bulbs, the contact ratings are lower. This is rarely a problem, as
lighting is low power and the contacts are usually rated for 13A to control
heaters and the like. This design requires a neutral connection. And gets
power between the unswitched live input and the neutral.

The other type of switch doesn't require a neutral connection. They run
entirely inline on the live connection. This enables them to be a direct
replacement for a light switch where no neutral is available. When they want
to switch on, they go almost a complete dead short, and extract the energy
required to run by having a tiny voltage drop. When off, they get energy by
simply taking it between the two terminals. This means that a tiny current
will flow through the load. As this is usually a filament lightbulb, this is
no problem and the current is too tiny to be noticed. However, an energy
saving bulb is a discharge tube that will not pass any current until a high
voltage is presented. This means that the switch doesn't get the tiny flow
of current required to power the electronics and will not work. Sometimes,
the problem is even worse and the small current passed by the electronics
builds up voltage in the bulb's starting capacitor meaning that the bulb
will flash every minute or so. This depends on the design of the bulb's
electronics.

So, whether it will work or not depends entirely upon the design of the
timer switch.

Christian.

In article ,
Mr Lawes wrote:
I read on the back of a box of Energy Saving Bulbs, that they are not
suitable for use with 'timing devices'.

That should have read 'with some timing devices'

I've got a couple of table lamps that are on for about five hours a
day, triggered by time switches.

What would be the consequence of using Energy Saving Bulbs in these
table lamps?

If they work, none. The problem can arise with the sort of time switch
that replaces a wall switch so has no dedicated neutral - relying on the
one passing through the load.

Or some with an electronic 'relay' - this may not like the inductive load.

So you need the instructions for the timer - if it places no restrictions
you should be ok.

If you've got the timers but lost the instructions, a guide would be
whether you can hear a relay click when they switch - these should be fine.

--
*No radio - Already stolen.

Dave Plowman London SW
To e-mail, change noise into sound.

"Christian McArdle" wrote in message
. net...
What would be the consequence of using Energy Saving Bulbs in these
table lamps?

It depends on the timing device. These usually work in two different ways.

The more expensive types and those with higher ratings use an
electromechanical switch called a relay. These can switch most types of
load, although whilst switching slightly reactive loads such as energy
saving bulbs, the contact ratings are lower. This is rarely a problem, as
lighting is low power and the contacts are usually rated for 13A to
control
heaters and the like. This design requires a neutral connection. And gets
power between the unswitched live input and the neutral.

The other type of switch doesn't require a neutral connection. They run
entirely inline on the live connection. This enables them to be a direct
replacement for a light switch where no neutral is available. When they
want
to switch on, they go almost a complete dead short, and extract the energy
required to run by having a tiny voltage drop. When off, they get energy
by
simply taking it between the two terminals. This means that a tiny current
will flow through the load. As this is usually a filament lightbulb, this
is
no problem and the current is too tiny to be noticed. However, an energy
saving bulb is a discharge tube that will not pass any current until a
high
voltage is presented. This means that the switch doesn't get the tiny flow
of current required to power the electronics and will not work. Sometimes,
the problem is even worse and the small current passed by the electronics
builds up voltage in the bulb's starting capacitor meaning that the bulb
will flash every minute or so. This depends on the design of the bulb's
electronics.

But if you do have one of these, wiring a low wattage pygmy bulb in parallel
with the energy saver will overcome the problem.

"Christian McArdle" wrote in message
. net...
What would be the consequence of using Energy Saving Bulbs in these
table lamps?

It depends on the timing device. These usually work in two different ways.

The more expensive types and those with higher ratings use an
electromechanical switch called a relay. These can switch most types of
load, although whilst switching slightly reactive loads such as energy
saving bulbs, the contact ratings are lower. This is rarely a problem, as
lighting is low power and the contacts are usually rated for 13A to
control
heaters and the like. This design requires a neutral connection. And gets
power between the unswitched live input and the neutral.

The other type of switch doesn't require a neutral connection. They run
entirely inline on the live connection. This enables them to be a direct
replacement for a light switch where no neutral is available. When they
want
to switch on, they go almost a complete dead short, and extract the energy
required to run by having a tiny voltage drop. When off, they get energy
by
simply taking it between the two terminals. This means that a tiny current
will flow through the load. As this is usually a filament lightbulb, this
is
no problem and the current is too tiny to be noticed. However, an energy
saving bulb is a discharge tube that will not pass any current until a
high
voltage is presented. This means that the switch doesn't get the tiny flow
of current required to power the electronics and will not work. Sometimes,
the problem is even worse and the small current passed by the electronics
builds up voltage in the bulb's starting capacitor meaning that the bulb
will flash every minute or so. This depends on the design of the bulb's
electronics.

So, whether it will work or not depends entirely upon the design of the
timer switch.

So following on from our earlier discussion about using one
of these "switch replacement" timers to control a relay which
in turn controls a lighting circuit, will the relay pass a small
current without actuating the switch, therefore allowing the
timer switch to continue operating when the lights are off?

TIA,
Al

In article ,
Al Reynolds wrote:
So following on from our earlier discussion about using one
of these "switch replacement" timers to control a relay which
in turn controls a lighting circuit, will the relay pass a small
current without actuating the switch, therefore allowing the
timer switch to continue operating when the lights are off?

It would depend on the relay. It might just stay on, as they need little
current. If it did, you'd have to increase the current it draws by either
wiring a small bulb or suitable power resistor in parallel with it.

--
*It's lonely at the top, but you eat better.

Dave Plowman London SW
To e-mail, change noise into sound.