blowing lightbulbs

this really isnt industry or plc related,,but heres my problem for those familiar with single phase,,

i have a 1973 mobile home and go through lighbulbs monthly,,its not just on one circuit,,its every circuit,,ive checked current draw with my ampprobe,,and see no fluctuations,,same with voltage,,but my meter might not be able to keep up with the spikes(if thats the problem),,could i have common problem?im more familiar with 3 phase,,so this is kind of new to me,,i doubt it could be a ground problem,,but i could be wrong,,how would i go about troubleshooting this aside from looking for the obvious,,(corroded terminals,,etc),,

the home is fed from a 200amp breaker and we are prone to power outages for brief seconds up to many hours being we are out in the boonies,,

Fred Raud

I used to blow a lot of light bulbs at my house, cause was high voltage, I'm getting 125 volts, instead of 120 (may peak higheer some times). Called power company and they said 125 was within tolerance. So...I switched to 130 volt bulbs, and bought some of the new flouresent (sp) replacements also. Problem solved.

What's you're voltage reading?

Fred,

How much is your mobile home insured for?

elevmike,,missed you in chat,,

no insurance on the place yet,,but im guessing your implying i should get some,,lol,,and some smoke detectors,,

and 122.4v

Fred Raud

Neutral Connection

You may have lost your neutral, or it might not be real tight. I have seen this but it was obvious. Part of the lights were brighter than others. If you could perfectly balance your loads, you wouldn't need it, but that is a theoretical. If you verify it to the panel, the power company would check it for you from the service lateral out. I have heard the 120 v/s 130 arguments, but as far as I know that is how they achieve the 40Watt ect ratings. I am no bulb expert though. Hope this helps.

One possibility is this. If you have 2 phases coming in, each being 120 VAC to ground and one of the phases gets grounded but yet there is a resistence to the earth ground 0V potential, you now have your
bulbs connected across two phases and instead of 120 VAC your voltage is now double, that would blow your bulbs.
You could get a bulb that is designed to operate at 240 VAC and
connect it to one of the phases and a ground ( at 120 VAC).
Normally the bulb would be dim but if you do experience the
problem I have described the bulb would light up and that would be
the proof positive of the above scenario.

I would also tend to believe that the neutral is loose in the panel also. I worked at a jobsite where that was happening while we used the old panel. Found that the neutral was loose and every time someone turned on the table saw the lights would get really bright.

im heading to the panel now,!

Fred Raud

Sounds like a neutral problem. The 125v wont hurt anything but can cause regular incandescent bulbs to have a shorter life span but normally not that noticeable.

Loss of or a poorly connected neutral at the source can cause voltages that far exceed the bulbs or any 120vac devices rating....TV's, radios etc. This is due to the neutral becoming a power leg from connections thru other circuits.

I have an old house and started using the fluorescent light bulbs that were mentioned. They cost more but last longer and the power bill decreased significantly immediately after I started using them.

A fluorescent bulb can produce 5x the light (lumens) with the same power used by an incandescent bulb....ie a fluorescent bulb may create the same light as a 100 watt incandescent bulb but use 20 watts of power.

This may help understand them better: http://home.howstuffworks.com/question236.htm

Of course the cost may be greater than 5x but many offer a 7 year or greater warranty.

i went out to check the panel,,and found alot of 'nests' in it,,wasp nests,,etc,,needs a good cleaning,,im going to blow it out soon,,

as far as fluorescents,,we are looking at it,,our biggest expence has been with our a/c,,but every bit does count,,ill let you know,,

i was only at the box for our supply for a minute or so before getting attacked by fire ants,,so i cut off that investigation soon,,tomorrow im going out with poison,,lol


Fred Raud

Many (most) mobile homes in that era used Federal Pacific breaker panels.

If so, MOVE OUT until it is replaced!

The bustabs would heat up and lose contact, then heat up more, etc until they were very loose, then really heat up and cause a fire.

They were eventually outlawed for use in the US.

They sent the manufacturing equipment to Mexico, and are still being produced down there.

regards.....casey

PS They were mentioning loosing neutral. Wouldn't urt to check all connections in the panel.

When I swap out an old panel, I typically find over half the screws loose.

I use to replace 5-8 bulbs in the house every month: our voltage is relatively stable at 122V, but had no luck.
I used all possible brands, including "loger life" and 130V - nothing helped.
2 years ago I decided to try new flouresent and bought set of 4 - all probems gone!
Much less power consumption with very bright light.
I am using mostly 14W bulbs now almost in every possibe place.
The best thing - none of them is dead yet.
They claim 7 years - will see how it goes.
Try it - you will love it.
Home Depot sells large contractor packs for less than $2 per bulb.

If you haven't considered it yet you might want to think about vibration, the real life mechanical kind. It doesn't take long before enough of the tungsten in a filament is gone to produce a mechanical weak spot. Add a little shaking and you have a broken filament. I don't have any bright ideas on how to isolate this. But I would suspect a compact flourescent would tend to be less touchy this way.

Keith

back when I was just a kid, I remember my father’s appliance repair shop filling up (literally) with TV sets all of a sudden ... I can remember one customer after another raising Cain because they wouldn’t be able to get their set back in time for “Wagon Train” on Wednesday night ...

the problem was that the filaments in all of the TV tubes were burning out ... this was happening all over town ... when the dust finally settled, it turned out that the real root of the problem was a recent political revolution way down in South America that had disrupted all of the copper shipments ... the global price of copper had gone sky high ...

and so ...

the local winos were going around from one power pole to the next and cutting the power company’s neutral conductors off and selling the copper for scrap ... naturally the money was being used to buy cheap wine ... with enough conductors missing, the neutral in all of the neighborhood houses starting “floating” ... and the TV tube filaments and assorted light bulbs were blowing out like crazy all over town ...

basic idea: consider a 240/120 VAC household circuit where 10 amps happens to be flowing through “L1” to supply a certain number of 120 volt lamps ... and suppose that there are also 10 amps flowing through “L2” to supply an equal number of 120 volt lamps on that circuit ... question: how many amps are flowing through the neutral conductor? ... answer: zero amps ... and incidentally, that’s why the neutral conductor doesn’t have to be twice as big as the “line” conductors ... specifically, if everything is working correctly, then the amount of current that the neutral will ever have to carry is the “imbalance” between the two “line” conductors ...

now ... suppose that the “L1” and “L2” loads remain perfectly balanced as described above ... in that case we could totally disconnect the neutral conductor and all of the bulbs would continue to function perfectly ... but ... suppose that once the neutral is disconnected, we start tuning off all of the bulbs on the “L2” circuit one-by-one ... each time we turn off another “L2” bulb, the remaining “L2” bulbs must carry more and more of the current which is still flowing through all of the “L1” bulbs ... oops! ... a voltage divider circuit is produced ... the “L1” bulbs get dimmer and dimmer ... but the remaining “L2” bulbs get brighter and brighter ... finally the “L2” bulbs start to blow out ...

things to watch for while testing for this type of problem ... a “weak neutral” might not show up at all if the loads on “L1” and “L2” happen to be approximately balanced while the test is being made ... often you have to turn on a heavier load like a toaster or iron, etc. to make the situation more evident ... you usually stand the best chance of finding the problem if you closely watch the voltage on one “line” while someone else cycles “off-and-on” some type of heavy (high amps) 120 volt loads on the other “line” ...

hope this helps ...

One problem with that sceneario is losing a source neutral with balanced loads is there is no way the load will be exactly balanced.

If in the real world it was "exactly" balanced then all 120vac devices would lose power because of no connection, the balance would negate the other legs being used as a neutral type connection.

Another issue is when ground is bonded to neutral but is not sufficient to act as a neutral, this can create issues with balance of currents when the neutral is loose or lost.

Another thing is that the neutral does carry current, the idea is to minimize how much when possible.

Connections are the first thing to look at.
Older housing etc the wire is another...rats chewing, oxidation etc can increase the resistive nature and cause voltage drops or other problems.

The idea of using toasters, heaters or any high wattage resistive load to see if lights flicker etc is a good one. It can be a strong indication of wiring issues.