unusual equipment failures in residence

[philhanna@comcast.net]

Resident of a new house with a 400A, 240/120 service complains of short lamp lives (replaced some 4 times in 3 years), sump pump failure after 3 weeks, repeated blown fuses on well pump, motor in bathroom fan failed, air conditioner motor failed,garage door opener failed, TV took long time to come on and eventually power supply failed, computer printer failed and telephones failed. Utility checked their incoming voltage with 3 day meter and says that it is 242v and steady. Does anyone have any ideas on what could be causing all these failures?

 

[Sierrasparky]

poor nuetral or ground.

Measure for ground current.

check telephone ground.

 

[gar]

110615-1607 EDT

philhanna@comcast.net:

Mount two lamp sockets on a board close together, but with about 1/2" between 100 W bulbs if they were installed. Three inches center to center should be good.

Attach two cords with plugs to the sockets. No connection between sockets. Install two 15 or 25 W incandescent lamps, both of the same wattage. 100s are way too bright to look at. 15s are probably optimum.

Find two receptacles near the main panel, but on opposite phases. You can verify that you are on different phases by measuring the voltage between the two hot wires. Should be around your 240. If both are on the same phase the difference is near zero, but so is the difference between neutrals.

Watch the relative brightness as different loads come on. You can use a 1500 W heater as a test load.

Assuming the air conditioner motor is 240, then both bulbs should quickly dim a little when it starts. Should not be too much difference between a bulb and itself when the air conditioner motor turns off. You can also monitor the voltage with a good DVM at the same time.

Next when nothing else is cycling on and off plug the 1500 W heater in to some circuit, but not the ones to which the bulbs are connected. If one bulb gets bright and the other dims, then there is a neutral problem. Also you could be monitoring one 120 V phase with a DVM at the same time.

A three volt change on a 120 incandescent should be noticeable to you.

See if you can learn anything from these tests.

.

 

[Dennis Alwon]

Are you in a high lightning strike area. I have seen this in certain areas where lightning seems to repeatedly strike. I would change the bulbs to 130v bulbs and maybe install a surge suppression system on the house.

 

[cadpoint]

If it's that new ask if they got construction pictures?

QA all the things that seem to be the problem!

Isolate and QA the same with a meggar if possible!

Just from reading it, sounds like a lot of nails in the wires! JMO...

Welcome to the forum!

 

[kwired]

Just from reading it, sounds like a lot of nails in the wires! JMO...

You want to help me understand why this would cause the problems mentioned?

As far as I know a nail in a wire will either:

A: contact only one conductor and no other conductive material and cause no noticeable problem.

B: contact an ungrounded conductor and another grounded object and cause overcurrent device to trip.

C: contact two or more conductors of different voltage potential and cause overcurrent device to trip.

D: If hits conductor just right may separate conductor causing open circuit and nothing on circuit will work.

E: If it separates conductor as mentioned in D could bridge between the two sections of what was once one conductor. This could result in intermittent problems but will still be one of the situations in A through D.

 

[cadpoint]

...You want to help me understand why this would cause the problems mentioned?

Cause the nail doesn't have to touch the other circuit but break some of the insulation of the circuit it serves to cause problems.

The general problem failures are basic all resistive heating problems and or failures due on the draw of amps.

All your summaries are ideal conditional answers of a problem, seems they might have already gone there.

 

[kwired]

Cause the nail doesn't have to touch the other circuit but break some of the insulation of the circuit it serves to cause problems.

If the nail contacts a circuit conductor but is insulated from other potential it simply becomes an extension of the conductor. If it is not in contact with any other conductive material it will carry no load - will not be a problem until something conductive does contact it.

The general problem failures are basic all resistive heating problems and or failures due on the draw of amps.

Where is the resistive heating going to come from unless the conductor is completely severed and the nail bridges the gap? If that is the case there will likely be other signs of power quality problems and it certainly will not shorten lamp life. This particular situation will likely have periods when the circuit is open and nothing will operate. If it is new construction with AFCI protection the AFCI is supposed to protect from a series fault like this. OP has not mentioned any breaker tripping problems at all just equipment failures.

All your summaries are ideal conditional answers of a problem, seems they might have already gone there

I would not call them ideal. I see them as the basic possible problems that will occur in the event of a nail penetrating a conductor. Any time this happens one of those five situations should be true. Only the situation with the nail in series should be a problem for the equipment failures mentioned in OP but it likely will have additional symptoms that indicate there is a problem. Other situations either cause no problem to the load or result in tripping overcurrent device, this was not mentioned in OP.

 

[Sierrasparky]

I doubt this is because of a nail in a wire, If this is a new home there are AFC breakers and they should trip in the nail scenario.

 

[cadpoint]

Hopefully the OP will come back and state exactly what all the problems were.
It seems it been well presented as to what it might be!

To bad they did not state the nature of usuage for AFCI's, they didn't state their location for a time line reference and some circuits didn't require it anyway.

All that has been said doesn't make me wrong, the breaker is still working.

I'm glad that everyone that has read this now understands more of the why a breaker works and what exactly they might be looking weither they knew it or not.

Or just consider it an Ideal problem, let me pick this answer for it, yeah right!

 

[K8MHZ]

Utility checked their incoming voltage with 3 day meter and says that it is 242v and steady.

That does nothing to verify the integrity of the neutral. You could get the exact same results with the neutral removed entirely.

As I read the OP's complaint, it seems that most or all of the failures involve 120 volt devices. It should have been the 120 supply that was monitored. Have them come back and run a three day test on both the 120 legs and see what comes up.

 

[brian john]

poor nuetral or ground.

Measure for ground current.

check telephone ground.

You could operate for years without a ground, poor ground NAH! Without a neutral well that is a different thing.