light bulbs keep blowing

[shoemaker40]

the customer complained of light bulbs constantly blowing.( brand new home)i found multiple circuit neutrals tied together in a four gang switch box and three gang. i seperated the neutrals per circuit. Could this be the problem or am i missing something.

[peter d]

It's possible that the original contractor used really cheap, low quality light bulbs.

[Dennis Alwon]

the customer complained of light bulbs constantly blowing.( brand new home)i found multiple circuit neutrals tied together in a four gang switch box and three gang. i seperated the neutrals per circuit. Could this be the problem or am i missing something.

You did the right thing but I don't believe that was the problem. Try installing 130volt bulbs and make sure the wattage is correct.

[cowboyjwc]

I agree with Peter and Dennis, but I also think that you could be on the right track or you could have an open neutral somewhere.

[ohm]

the customer complained of light bulbs constantly blowing.( brand new home)i found multiple circuit neutrals tied together in a four gang switch box and three gang. i seperated the neutrals per circuit. Could this be the problem or am i missing something.

We found the same thing in a doctor's clinic and a neighbors house. I Measured the voltages with two different digitals. Read 250V called POCO, they said they were within limits but raced off to a substation. Problem on that street never happened again.

BTW 130V bulbs are worth their weight in gold. Had two electricians in a plant that did nothing but change bulbs. Replaced them w/ 130V and we didn't have to relamp for 5 years.

[Rick Christopherson]

You should also consider where these bulbs are located, especially if this new house has kids to go with it. I kept losing the stair lights leading to my workshop, but then I realized that my young son (back then) was sliding down the stairs. The vibration kills the bulbs pretty quick. The same can be true for large rooms where the floor and/or ceiling are generally unsupported. The more open space a house has, the more it will bounce.

[vinster888]

now, say you have the original problem, with 1 recessed can in a series of six. the one bulb that keeps getting replaced is in the middle of the line. im down to thinking it must be the socket itself, all the joints have been remade, voltage is consistent

[mivey]

now, say you have the original problem, with 1 recessed can in a series of six. the one bulb that keeps getting replaced is in the middle of the line. im down to thinking it must be the socket itself, all the joints have been remade, voltage is consistentProbably. I have two of sixteen cans like that at home but haven't felt like fixing them. Also, consider insulation laying over a non-IC can.

[LarryFine]

If you believe vibration is the culprit, try heavy-duty or fan-light bulbs. They contain extra filament support wires.

[quogueelectric]

If you believe vibration is the culprit, try heavy-duty or fan-light bulbs. They contain extra filament support wires.
100% agree it is usually mechanical vibration that leads to the early demise of lights. Many times due to improper building construction such as a door cut in without a header /jack stud /king stud so every time the door is shut the light burns out.

[ohm]

100% agree it is usually mechanical vibration that leads to the early demise of lights. Many times due to improper building construction such as a door cut in without a header /jack stud /king stud so every time the door is shut the light burns out.

Sounds like a good place for a CFL

[TOOL_5150]

Sounds like a good place for a CFL

Or a rough service bulb

~Matt

[mikeames]

or you could have an open neutral somewhere.

How would this impact bulb life of only one?

[Ohmy]

How would this impact bulb life of only one?

Lot of times its the lead coming from the socket to the j-box on the side of the can housing. 9 times out of 10 the two white solid wires are twisted nicely but the little white stranded wire from the can pulls right out of the wire nut.

[Rick Christopherson]

Lot of times its the lead coming from the socket to the j-box on the side of the can housing. 9 times out of 10 the two white solid wires are twisted nicely but the little white stranded wire from the can pulls right out of the wire nut.That is not a floating neutral, it is a simple open circuit. A floating neutral requires both phases be present and share a common neutral which is disconnected from the source. It is a series connection of two (or more) 120 volt loads across a 240 volt supply, and the voltage of the floating neutral is dependent on the voltage division of the two loads.

[ohm]

That is not a floating neutral, it is a simple open circuit. A floating neutral requires both phases be present and share a common neutral which is disconnected from the source. It is a series connection of two (or more) 120 volt loads across a 240 volt supply, and the voltage of the floating neutral is dependent on the voltage division of the two loads.

True and if the lights in question are on a MWBC an open neutral could very well be the culprit, depending on where the open occurs in the branch circuits.

[Ohmy]

That is not a floating neutral, it is a simple open circuit. A floating neutral requires both phases be present and share a common neutral which is disconnected from the source. It is a series connection of two (or more) 120 volt loads across a 240 volt supply, and the voltage of the floating neutral is dependent on the voltage division of the two loads.

I agree with that. In that case, just get your lamps from Europe.

[LarryFine]

9 times out of 10 the two white solid wires are twisted nicely but the little white stranded wire from the can pulls right out of the wire nut.
A. It doesn't matter whether it's the white or the black that's loose. Current is the same everywhere in a simple circuit or loop.

2. The stranded wire wouldn't pull out if the installer was diligent enough to strip the wire long enough to go over the tips of the solids.

D. There's no reason undervoltage should shorten an incandescent filament's lifespan.

[Electron_Sam78]

A. It doesn't matter whether it's the white or the black that's loose. Current is the same everywhere in a simple circuit or loop.

2. The stranded wire wouldn't pull out if the installer was diligent enough to strip the wire long enough to go over the tips of the solids.

D. There's no reason undervoltage should shorten an incandescent filament's lifespan.

A, 2, & D? Home Alone? :grin:

[Ohmy]

A. It doesn't matter whether it's the white or the black that's loose. Current is the same everywhere in a simple circuit or loop.

2. The stranded wire wouldn't pull out if the installer was diligent enough to strip the wire long enough to go over the tips of the solids.

D. There's no reason undervoltage should shorten an incandescent filament's lifespan.

I agree with that. Its just that in my experience, while anecdodal in nature, is those problems are generally on the white, and generally caused by poor installation from the installer (who is obviously not as cleaver as you), and generally causes the arcing in the wirenut, which I find reduces the life on incandescent lamps. Just trying to contribute :)

[specgrade]

My mother-in-law asked me to figure out why she was replacing light bulbs ever other week. When I took a voltage reading I got 127.8 volts. I told her to start using 130 volt bulbs and she hasn't had a problem since.

[LarryFine]

A, 2, & D? Home Alone? :grin:Nope, Rocky 5.

[LarryFine]

I agree with that. Its just that in my experience, while anecdodal in nature, is those problems are generally on the white, and generally caused by poor installation from the installer (who is obviously not as cleaver as you), and generally causes the arcing in the wirenut, which I find reduces the life on incandescent lamps. Just trying to contribute :)I'm certainly not arguing or picking on you, just joining in on the discussion. :smile:

Is the suggestion that the wire conducts heat from the loose connection to the socket, or that arcing causes current spikes in the filament? :confused:

[mikeames]

I took the OP to mean that the bulb was working but burning out in a relativly short period of time ie: a week or a few days. If this one light was on a MWBC and the neutral was out is would never work for more than a few seconds. If it was a normal circuit and the neutral was not connected it would have no ill affect on the bulb any more than the switch being turned off.

[ohm]

I took the OP to mean that the bulb was working but burning out in a relativly short period of time ie: a week or a few days. If this one light was on a MWBC and the neutral was out is would never work for more than a few seconds. If it was a normal circuit and the neutral was not connected it would have no ill affect on the bulb any more than the switch being turned off.

Actually if it's a MWBC and the load on each phase is pefectly balanced the neutral does not carry current. If one side of the MWBC has more load than the other and the neutral is loose one set of lights may have 135V across them and the other side will have 105V.

[mikeames]

Ok but still not likely that this one fixture and one other device allowing the 135v is the only 2 loads on the circuit. My point with out going over everything is base on the post the neutral is likely not the problem. If it were a MWBC and it had a 135v accross it due to the open neutral there would be other issues in the house thus exposing the issue.

[cadpoint]

Ok but still not likely that this one fixture and one other device allowing the 135v is the only 2 loads on the circuit. My point with out going over everything is base on the post the neutral is likely not the problem. If it were a MWBC and it had a 135v across it due to the open neutral there would be other issues in the house thus exposing the issue.

But how could you not seperate it to the neutral in this situation...??? I ask!!! :grin:

[ohm]

Ok but still not likely that this one fixture and one other device allowing the 135v is the only 2 loads on the circuit. My point with out going over everything is base on the post the neutral is likely not the problem. If it were a MWBC and it had a 135v accross it due to the open neutral there would be other issues in the house thus exposing the issue.

If a MWBC that had lights and receptacles on it and a loose neutral screw in the SE panel or loose wirenut in a JB the problem may never show itself until the poor connection started to heat during a heavy load, like a portable heater

Then, the 240V would divide across the various resistances that happened to be turned on at the time.

If one phase only had one 100W lamp turned on and the other phase had a 10 A heater turned on, the lamp would have about 221.5V across it and the balance (18.5V) would be felt across the heater.

Again, the problem may never show itself until the heater and that one light was turned on.

[K8MHZ]

We live a stone's throw from an airport that was used for C-130 training. They would do touch and goes over our house for hours on end.

If we were lucky, we would get 2 or 3 weeks bulb life out of our front door light.

The county lost the 27,000 dollar a year contract for airport use and we haven't had a Herc fly over in nearly a year now. Same bulb in the front door light since.

I figure we will save about 25 bucks a year on bulbs, as will many of our neighbors.

A C-130 at less than 200 feet over your house gives off some pretty good vibes. Once every 11 minutes or so.....

[Teaspoon]

When Installing multiple lights,Controlled by the same switch .
I pig tail the black & white wires. This way the smaller fixture wire is one on one with the larger switch leg wire & neutral. i think making a better connection.

[mivey]

When Installing multiple lights,Controlled by the same switch .
I pig tail the black & white wires. This way the smaller fixture wire is one on one with the larger switch leg wire & neutral. i think making a better connection.You may be violating code because the pigtail is part of the branch wiring and must be sized according to the breaker on that branch circuit.

[mikeames]

If a MWBC that had lights and receptacles on it and a loose neutral screw in the SE panel or loose wirenut in a JB the problem may never show itself until the poor connection started to heat during a heavy load, like a portable heater

Then, the 240V would divide across the various resistances that happened to be turned on at the time.

If one phase only had one 100W lamp turned on and the other phase had a 10 A heater turned on, the lamp would have about 221.5V across it and the balance (18.5V) would be felt across the heater.

Again, the problem may never show itself until the heater and that one light was turned on.


I understand MWBC its not new, I don't need it explained. My point is this incident was described as having an impact on just one light, and nothing else. If it were a MWBC gone bad it would show itself in more than one place. If there are six lights on the same circuit they would all have the same problem. If there were electronic equipment on that circuit they may be damaged. Since the OP only mentioned one light and did not mention anything else I ruled out the MWBC. In addition to this if it were a MWBC circuit the brightness of the bulb/bulbs would vary depending on the load of the bad MWBC. This was no mentioned by the OP.

[mikeames]

But how could you not seperate it to the neutral in this situation...??? I ask!!! :grin:


Not sure what you mean there Cadpoint.

[ohm]

I understand MWBC its not new, I don't need it explained. My point is this incident was described as having an impact on just one light, and nothing else. If it were a MWBC gone bad it would show itself in more than one place. If there are six lights on the same circuit they would all have the same problem. If there were electronic equipment on that circuit they may be damaged. Since the OP only mentioned one light and did not mention anything else I ruled out the MWBC. In addition to this if it were a MWBC circuit the brightness of the bulb/bulbs would vary depending on the load of the bad MWBC. This was no mentioned by the OP.

As I stated in my last sentence, if only one light was turned on it would probably work OK with a loose neutral, since it's a light load. But if a heavy load on the opposite phase was turned on it may heat the connection and burn out the light....or it could just be vibration.

[cowboyjwc]

Lot of times its the lead coming from the socket to the j-box on the side of the can housing. 9 times out of 10 the two white solid wires are twisted nicely but the little white stranded wire from the can pulls right out of the wire nut.

Thanks Ohmy. :smile:

[short circuit faulted]

Has anyone used resistors in 120V lighting ciruits? I have not but recall early in my career reading competitors quote stating he would install resistors on OH lighting to increase lamp life. I am speaking about 25 years ago - back when vinyl was still king as a recording method but quickly being killed by CD.

Have a good day all!

Steve