We have been in this house quit a while, and I recall always having
We go through light bulbs like water. It is not uncommon for a light
bulb to last two or three weeks before I have to replace it again.
The bulbs always burn out right when the light switch is turned on. I
turn on the light switch, the light goes on for an instant, then burns
out. The bulbs don't ever burn out when the light has been on for a
So, I really feel like there is something not right about the
electricity in the house, as strange as that sounds.
I had this happening in the Condominium that I used to live in until about
a year ago. It happens to some extent in my new house as well. I didn't
have it quite that bad, but we did go through a lot of bulbs. I remember
once saying something like that about "electrical system probaby not quite
right" and he asked if the lights that burned out were on a ceiling that
had a floor above it. I said yes. He said it's likely that the vibrations
from walking above might be jarring the filaments in the bulb, causing
them to fail prematurely. Sounds reasonable, but is it the problem? I
can't say. Hope this helps some.
I had the same problem with a house I purchased a couple of years ago.
Turned out that there was a problem with the transformer at the street, and
I was getting serious over-voltage.
Check your outlets with a multi-meter. I think I was getting 135-140v on
110 v circuits.
Once this was discovered, the utility company jumped through hoops to
correct the problem.
On 13 Feb 2005 20:27:12 -0800, email@example.com wrote:
I had the same problems a few years ago. Had power company to come
out and put a recording volt meter on line. Found no problems.
Changed to higher quality bulbs.. problem solved. Some charities used
to sell great "lifetime" bulbs as a fund raiser.. They weren't
lifetime.. but lasted longer than what you get in grocery store.
note.. Having power company record incoming voltage won't show a
problem you may be having with your wiring inside of house .. such as
broken neutral line..
On 13 Feb 2005 20:27:12 -0800, firstname.lastname@example.org wrote:
That's very possible. The most likely cause is that the voltage is
too high in your house and that has given you shortened life on the
The question is what is causing this? The first thing you need to do
is get an accurate voltmeter. If you don't own one see if you can
borrow one from a neighbor. Measure the voltage at a few outlets
around your house. Repeat the measurements at various times of day.
You should be measuring no more than 125 volts (Assuming you are in
North America). Two quick possibilities...
1. If you get really weird High and Low readlings, such as 130+ volts
on some outlets and perhaps 100 or less volts on others, you most
likely have a loose or broken neutral problem. This is something that
a professional electrician will need to fix. This is a serious
problem and a fire hazard so you don't want to delay calling for
2. If every outlet reads a high voltage, say >130 volts, then most
likely the problem is with your power company, specifically, with the
power company's transformer serving your house. They should fix this
Perhaps the quickest way to determine the cause of the problem is to
call the power company first. They should send out a technician to
determine if the problem is yours or theirs and most will not charge
you for the visit.
After all other solutions fail - if they do - replace your light switches
with dimmer switches. "Turning up" the light may provide enough time for the
device to handle the surge. Also, running at 90% should lengthen the bulb's
If after investigating you find that everything is up to snuff with the
home's wiring, but the incoming voltage is on the high side, but not so
high that your utility will do anything about it, there are a few things
you can do:
1. Buy 130 volt bulbs. They are available through electrical supply
houses. You'll find they will last a LOT longer. They cost quite a bit
more than commonly available bulbs, and you won't get as many lumens of
light per watt consumed, but every convenience has its price.
2. You can buy thermistor "soft start" devices which go in the socket
under the bulb base and effectively eliminate the turn on current surge.
3. As others have suggested you can install solid state lamp dimmers and
remember to turn the lights on by bringing the dimmer up from zero.
That'll eliminate the turn on surge too.
4. I got annoyed at the frequency with which I'd notice one of the eight
"vanity" bulbs in our master bath burned out. Ten years ago I installed
a dimmer in that circuit and hid it in a box above the top of a medicine
cabinet. I set it slightly down from full on, and I don't think I've had
to replace more than a couple of those vanity bulbs since I did that.
Plus, the light is just a bit softer and redder, which helps us to
accept our morning mugs in the mirror. <G>
HD and Lowes also sell them,as "contractor" bulbs,in large packs,24 or more
bulbs.One of those two -used- to sell them in smaller,more practical
packs(for me),but I haven't been able to find them lately.
I prefer to use the 130v bulbs.
I had a 130V 100W bulb last for 14 years in the globe in my dining room,and
it was on a dimmer,but I turned it on and off normally but not dimming to
'out',but at about a 85 % level.
Ordinary incandescent bulb filaments gradually erode and become thinner,and
finally,the turn out surge is what kills them.
Yeah, and sometimes when they burn out you'll get a "tungsten arc"
effect where an arc starts burning between the broken filament ends and
keeps melting back along the two filament pieces until it is arcing
directly between the filament connecting leads. That arc can be a low
enough resistance to cause a fuse to pop or a breaker to snap.
When you get a "tungsten arc" it usually occurs just as you switch on
the bulb and you may notice a brief brighter than normal flash of light,
it's all over in a moment.
Some light bulbs are/were made with a "fuse link" built into one of the
leads intended to blow under those arcing conditions to avoid your
having to reset a breaker or replace a fuse.
I don't thing the long life I'm getting is from a "soft start", which to
my understanding is a slow increase in voltage/current which takes maybe
a second or so and never lets the current get to the high levels it will
reach when a cold bulb filament is suddenly connected to full power. I
suspect the thermal lag in a good sized bulb's filament may be enough so
that not much is gained just by having the first half cycle of power to
the bulb start at a zero crossing, though that can't hurt either, can it?
I'd rather go with the theory that running the bulbs a bit down from
their rated power is akin to using 130 volt bulbs, and the evaporation
rate of the filament is down by whatever exponential ratio fits the
reduced power, and thus they "last longer".
And yes, I do have the original wall toggle switch ahead the dimmer.
Don Klipstein should check in here about now, he's my acknowledged light
bulb guru. There's more than you probably ever wanted to know at his
Your point is taken, that "soft start" does not *necessarily* consist of
zero-crossing start. Your point is also taken that the low resistance of a
light bulb changes to a much higher resistance, once the filament heats up.
For a brief time, a hugh inrush of current is possible due to the initial
low resistance of the light. That is indeed more likely the culprit in lamp
mortality, than mere lack of starting at zero-crossing.
I recall from years ago that triac implies start at zero crossing. Lutron
website says all of its dimmers have triacs as the essential elements. So
any Lutron dimmer would seemingly assure startup at zero crossing.
Your recollection may be inaccurate. Triac light dimmers actually work
by assuring AGAINST zero crossing startup. Except when full-on or off,
the dimmer operates by delaying the current with respect to the voltage
zero crossing, 120 times per second. When at 50% duty cycle (about 1/2
power), the current starts 1/4 cycle behind the voltage, i.e. at the
PEAK of the voltage sinewave, and stops when the voltage passes through
zero, so only the last half of each positive and negative half-cycle is
Some heater controls modulate power by energizing the element for a
certain number of full cycles, deenergizing for some number of full
cycles, and so on. Here, zero crossing can be employed. This scheme is
not so good for lighting because the "blink rate" is well below 60 Hz
and would be quite noticable.
The question to be answered is how much of a difference does it make
using the last half of the sine "bump" vs. the first half, in terms of
energy imparted to the filament per cycle, taking into account the mass
and heat capacity of the filament, etc. etc.
I suspect that during rapid warmup, one segment of the filament gets
hotter than the rest, which makes its resistance go up higher, which
means it receives more power than than its neighboring segments which
still have lower resistance. Since it receives more power, it heats up
even faster and resistance increases even more. The hotter segment also
expands more rapidly and suffers greater mechanical stress and fatigue
as a result, becoming a likely point of failure.
Bringing the current up slowly, over the course of a second or so,
allows time for all segments to heat at closer to the same rate, as
well as time for heat to diffuse from one segment to another, allowing
more uniform heating and greatly reducing the chance of a local hotspot
Some of these ideas can be demonstrated by experimenting with bulbs in
series, which is effectively a single filament divided into segments.
Say you have a car battery (12V) and 5 to 10 identical automotive bulbs
in series. When you complete the circuit, you'll see that one gets
initially brighter than the others, then it may even get dimmer as the
others "catch up" to finally achieve uniform brightness. That's because
even though they are "identical," there are slight differences in the
bulbs and the one with the highest initial resistance and/or the
quickest heating filament will absorb most of the power till the others
heat up. I noticed this effect when I was about 6 years old, though I
had no idea what was causing it; I just knew I could rearrange the
order of the bulbs in series till they lit up from left to right and it
was pretty cool.
I've never noticed that effect, but it seems possible.
I'm guessing it was holiday lighting (Xmas tree strings) you were
experimenting with when you were around age 6, right?
I'm having a hard time visualizing what ten 12 volt bulbs across a 12
volt battery would end up doing. Wouldn't seem like there'd be enough
voltage available to produce anything other than infrared "uniform
brightness" with just 1.2 volts across each bulb, or did you misspeak
about the battery's voltage?
Oh, and my face is red for geting lured into agreeing that triacs
"switch on" at zero crossings. I know better, but it's been so long
since I built anything with triacs that I forgot that they "latch on"
once triggered and have to wait for a current zero crossing to drop out.
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