Porch Light Bulbs Failing

Is the light next to a door? Maybe the door is slamming closed harder and jarring the bulbs. Some of those motion sensor lights are soft start. Maybe it's coming on full bright to start now.
 
Makes no sense but try this.

Take bulb from other light and try it.

If it lasts then bad batches of bulbs.

WAIT...Check voltages it both fixtures and maybe a few outlets.

We had squirrels eat the neutral on the pole and all 240 vac things were fine but everything else was wonky and flipping on a light made everything different.

If you have a poor neutral L1 could be spiking while L2 dipping.

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in a word, RESISTANCE!
if the resistance rises, either amperage and /or voltage must increase to do the same work

i'd check the Neutral to the light .
you could have a faulty SSR or receptor

there is di-electric grease that you can put on a bulb tip to reduce resistance and prevent oxidation of the contact surfaces

Thanks, Mike. That is one of the answers I've seen on a couple of my searches, but not explained as well. I've seen several mentions of the problem being at the neutral.
I have used WD-40 on my light bulb connections for years, and it seems to help. If nothing else, the bulb screws in and out easier, as they tend to dry out after extended use and get stuck. I've seen WD-40 pull off what seemed to be electrical miracles many times.

I had surgery a couple weeks ago and haven't been very mobile. I think I'm up to pulling the fixture off and checking the connections tomorrow.
 
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Since you've had failures with three different technologies, I would think that would rule out the bulbs.
I think TQ is on to something. A bad neutral connection somewhere in the circuit would shift the balance depending on the relative load on each half of the circuit.

I had a problem like that years ago. Whoever had done the wiring from the meter at the barn to the house didn't bother to run a neutral wire. They depended on the connection to a water pipe from the barn to the house. At some point before I moved in, the original steel pipe was replaced with polyethylene which in effect broke the electrical connection. Current through the neutral was maintained by conductivity of the water and the ground. Depending upon what the loads were on either leg, I had seen voltage swings as much as 40 volts. I ran new service wiring and it ended the problem.
 
Well, I opened it up this afternoon and think I found the problem. Both the common and hot wire were stranded and connected to solid copper with old ceramic connectors. I re-stripped the insulation for fresh stranded and cleaned the solid, applied a little WD-40 and reattached them with newer connectors that use the little wire spiral to screw on. Those connectors should dig in to make contact with both the stranded and solid wires.

I put a new bulb in it and I guess I'll have to wait to see what happens. It won't come on until dark, anyway. If that doesn't work, the next place to look is at the connections at the wall switch.
 
Franko, I guess the question that I didn't ask is..." when the lamp burned out, did you take it to another socket to verify that it was indeed open. If you did then I am still not sure why a bad connection would cause the lamp to fail open. However if you didn't then an intermittent joint surely could have been the issue.

David
 
Yes, I checked the bulbs in a different fixture. They were dead.
 
in a word, RESISTANCE!
if the resistance rises, either amperage and /or voltage must increase to do the same work...
WRONG!
In a totally series resistive circuit (wire and light bulbs) and a constant power source(120VAC), as the resistance goes up the current goes down. A bad contact (R2) will only add the resistance of the lamp(R1) and reduce the current. Do the math: I=E/R
Normal connection: I(current)= E(120V)/R1(lamp)
Bad connection= I (current)= E(120V)/R1 (lamp)+R2(contact)

I would look at neutral connections in the box or at the pole. Had this happen at my parents farm house. Lamps in some rooms lasted forever and in others, blew at short random times. Loose neutral at the pole.

Ken
 
WRONG!
In a totally series resistive circuit (wire and light bulbs) and a constant power source(120VAC), as the resistance goes up the current goes down. A bad contact (R2) will only add the resistance of the lamp(R1) and reduce the current. Do the math: I=E/R
Normal connection: I(current)= E(120V)/R1(lamp)
Bad connection= I (current)= E(120V)/R1 (lamp)+R2(contact)

I would look at neutral connections in the box or at the pole. Had this happen at my parents farm house. Lamps in some rooms lasted forever and in others, blew at short random times. Loose neutral at the pole.

Ken


I'm not wrong, you missed my point

TO DO THE SAME WORK the amps and/or voltage must increase if the resistance raises

resistance adds heat to a circuit, the heat increases the resistance further. if there is no spare voltage, the amps must raise to do the same work
 
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A light bulb can't do the same work, unless you can find a way to suck the light out of it, so it will only get dimmer. Imagine two bulbs in series - they just dim due to the voltage drop because of the resistance. Think old school rheostat dimmer. A motor driving a machine, however, would over heat due to the load placed on the motor to try to do the same amount of work.
I could see a poor connection causing a flicker in the lamp which would increase the thermal shock to the lamp.
If this is a multi-wire branch circuit then the current could increase through the lamp because of the two sides of the circuit trying to balance out without a neutral to carry the unbalanced load to the panel.
 
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