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Red Squirrel 09-25-2009 02:57 PM

light bulbs keep burning
 
I've heard of this issue before and it's usually related to overvoltage. In my new house I've already had like 3 bulbs burn out, they are the "spot light" type bulbs. The voltage hovers at 120-121v on one leg and around 119-120 on the other, it drops maybe 1-2 volts if I turn all the rounds on the stove on, so seems pretty normal to me. Could there be spikes that my volt meter is just not catching?

I'm scared that this may affect my PC equipment.

jbfan 09-25-2009 04:15 PM

Loose connectios at the switch can also cause a spike that takes out the bulbs.

Yoyizit 09-25-2009 04:26 PM

Quote:

Originally Posted by Red Squirrel (Post 332462)
I've heard of this issue before and it's usually related to overvoltage. In my new house I've already had like 3 bulbs burn out, they are the "spot light" type bulbs. The voltage hovers at 120-121v on one leg and around 119-120 on the other, it drops maybe 1-2 volts if I turn all the rounds on the stove on, so seems pretty normal to me. Could there be spikes that my volt meter is just not catching?

I'm scared that this may affect my PC equipment.

You'd need a storage oscilloscope to find those spikes. It could be a bad batch of bulbs or it could be mechanical vibration.

With your PC having a switchmode power supply I doubt that these kinds of spikes could get through.

With a 1-2 volt drop in the 240v under the heavy 240v load of your stove, are you very far from your pole 'former?

You might want to check your neutral connection.
Put a 10A 120v load on one side of the neutral with all other outlet breakers on both sides off.
You shouldn't notice any voltage increase on the other side of your neutral.

Red Squirrel 09-25-2009 11:37 PM

Quote:

Originally Posted by Yoyizit (Post 332507)
You'd need a storage oscilloscope to find those spikes. It could be a bad batch of bulbs or it could be mechanical vibration.

With your PC having a switchmode power supply I doubt that these kinds of spikes could get through.

With a 1-2 volt drop in the 240v under the heavy 240v load of your stove, are you very far from your pole 'former?

You might want to check your neutral connection.
Put a 10A 120v load on one side of the neutral with all other outlet breakers on both sides off.
You shouldn't notice any voltage increase on the other side of your neutral.

It's funny as I am pretty sure I hear the transformer, but I can't see it. It's on a pole and the lines pass behind my house. I am pretty sure there are several houses on the same transformer. There's a very thick lower cable that passes so I'm guessing that is 240 ~1kamp service and the houses are branching off of it and mostly all have 100amp service. So maybe 10 houses per transformer? Just guessing here mind you. I definably don't have my own dedicated one.

The bulbs are cheaper brand, so maybe it could be a bad batch, but just odd as they were all different types. One was a shower bulb. Burnt the day it was installed, another was a track light spot bulb (similar to the shower one) and the other was a 3 way bulb.

Though, the voltage changes with high load are not normal? I figured it would be.

Also what would be a good 120v load to test with? Would the microwave or toaster work (maybe both at once if on same leg)? I don't have a blow dryer or curling iron being a single guy. :p

Yoyizit 09-26-2009 10:28 AM

Quote:

Originally Posted by Red Squirrel (Post 332660)
It's funny as I am pretty sure I hear the transformer, but I can't see it. It's on a pole and the lines pass behind my house. I am pretty sure there are several houses on the same transformer. There's a very thick lower cable that passes so I'm guessing that is 240 ~1kamp service and the houses are branching off of it and mostly all have 100amp service. So maybe 10 houses per transformer? Just guessing here mind you. I definably don't have my own dedicated one.

The bulbs are cheaper brand, so maybe it could be a bad batch, but just odd as they were all different types. One was a shower bulb. Burnt the day it was installed, another was a track light spot bulb (similar to the shower one) and the other was a 3 way bulb.

Though, the voltage changes with high load are not normal? I figured it would be.

Also what would be a good 120v load to test with? Would the microwave or toaster work (maybe both at once if on same leg)? I don't have a blow dryer or curling iron being a single guy. :p

The voltage change with load depends on the wire resistance and length. A single 100' conductor of #14 AWG copper should come in at about 0.26 ohm or slightly higher, so 10A through it should give you a drop of 2.6v across that length of wire.
I think an NEC design req'mt is a 5% drop from the load center to the farthest outlet.

Use a toaster oven. You get better readings if you watch for the voltage rise when you turn it off.
Use the heaviest load you can conveniently hook up without the breaker tripping.

These bulbs probably have a rated lifetime on the carton which means half should last that long. If you tested a batch of randomly selected bulbs at rated voltage I doubt that this rated lifetime would be achieved. I don't know what to think about this but a lot of houses could probably use a buck transformer to drop the voltage slightly. All their stuff would last longer.
It is in PoCos interest to raise the voltage because it raises your bill. There is no incentive for them to lower your voltage that I know of.

Billy_Bob 09-27-2009 10:22 AM

If it was a problem with the power voltage, then all the bulbs in your house would be going out!

The problem as I see it is greed and large corporations. Replace the bulbs more frequently and they make more money!

It used to be that light bulbs lasted for years. Then suddenly they stopped lasting so long. And they seem to be getting worse and worse.

In the past I have switched to a different brand and suddenly had lightbulbs which lasted longer.

Then I switched to compact fluorescents and same problem again. Some bulbs did not last very long. I tried another brand and those last longer.

In my car I replaced a dome bulb 3 times in one month! They kept burning out! I got disgusted and switched to an LED light which has been working fine.

Yoyizit 09-27-2009 10:32 AM

Quote:

Originally Posted by Billy_Bob (Post 333153)
In my car I replaced a dome bulb 3 times in one month! They kept burning out! I got disgusted and switched to an LED light which has been working fine.

The voltage across your battery at fast idle should be
between 13.3v (summer) and 15.5v (winter). If it's higher your voltage regulator could be defective, which means you are overstressing your car's entire elec. system.

Scuba_Dave 09-27-2009 10:41 AM

I hope you are keeping the recipts & bringing the bulbs back
I would

Gigs 09-27-2009 06:51 PM

Quote:

Originally Posted by Red Squirrel (Post 332660)
It's funny as I am pretty sure I hear the transformer, but I can't see it. It's on a pole and the lines pass behind my house. I am pretty sure there are several houses on the same transformer. There's a very thick lower cable that passes so I'm guessing that is 240 ~1kamp service and the houses are branching off of it and mostly all have 100amp service. So maybe 10 houses per transformer? Just guessing here mind you. I definably don't have my own dedicated one.

That's very unlikely. The thick lowest wire is almost always cable or phone, not power.

Don't count on this for safety purposes, but it's a pretty good bet.

AllanJ 09-27-2009 07:25 PM

The 120/240 volt wires and the ground wire often form a threesome on the utility poles separated by a few inches from one another. Another common arrangement is for the two hots to be wrapped around the ground in a long spiral.

kbsparky 09-27-2009 08:34 PM

Quote:

Originally Posted by Red Squirrel (Post 332462)
....I'm scared that this may affect my PC equipment.

What is the input voltage value listed on your computer equipment?

Most computers' power supplies these days are rated for anything from 100-240 Volts. Variances of a couple volts on a 120 Volt supply won't do diddly-squat to such power supplies.

Scuba_Dave 09-27-2009 08:43 PM

Quote:

Originally Posted by Red Squirrel (Post 332462)
I'm scared that this may affect my PC equipment.

My LCD & my Computer are both plugged into UPS
Cheap insurance VS the cost of either

Red Squirrel 09-27-2009 08:55 PM

yeah I use UPS for mostly everything, so that should protect it fine from these spikes? I've always wondered if the "AVR" they advertise really works or not.

Billy_Bob 09-28-2009 09:57 AM

Quote:

Originally Posted by Yoyizit (Post 333156)
The voltage across your battery at fast idle should be
between 13.3v (winter) and 15.5v (summer). If it's higher your voltage regulator could be defective, which means you are overstressing your car's entire elec. system.

The voltage in my car is as it should be (testing with multimeter). Most of the other light bulbs in the car have never been replaced and are working fine.

The problem was with the new replacement bulbs being junk. I've read of other people having similar problems lately on the internet (some automotive replacement bulbs)...


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