PetrosA
Senior Member
- Location
- Lancaster, Pennsylvania
I'm generally a pretty good basic level troubleshooter, so when I make a mistake, it's embarrassing, especially when I sit and think about it 
. I figured I'd analyze it here so others can learn from it too.
Service call to check an apartment losing power intermittently. The property manager had had someone (unclear who...) check the meter and main breaker and claimed that it was all okay, so the problem must be in the apartment. I was called in to check inside the apartment by a real estate manager who is generally a pretty astute guy. He explained that the problems started a few weeks back when there were some repeated issues with HV lines feeding the complex - a car hit a pole bringing lines down, then a branch came down taking another section of lines down, with the POCO making several repairs in a few days/weeks time. Since then lights and receptacles would go off together at various times in multiple rooms. Tenant claimed that turning on the central AC would sometimes cause this, but it would also happen with AC off in the middle of the night. He seemed to think it happened more often in the evening when people were getting home from work. He had also noticed that the lights were dimming pretty often, but since he only has incandescent lamps in a few places (the rest are CFLs), he couldn't say whether it was throughout the apartment.
About three or four minutes into the interview with the tenant, the lights went out for maybe five seconds, then came back on. I went and got a few meters to check both legs, checked the breakers, they were cool, wiggled them around and tapped on them, which didn't cause any flickering or outage. There were no sizzling or crackling sounds from the panel. Voltage read steady on the main lugs although the lights did flicker very slightly from time to time. My setup only samples once per second for data logging, so it's possible I wouldn't see those dips.
I made arrangements to come back the next day when I could get to his main (in the electrical room) to check that out.
When the real estate guy called to make the arrangements the next day, the property manager took it upon himself to bring in another electrician to check the panel in the apartment. That guy claimed that multiple breakers and the bus bar were arc damaged and a panel change was in order. I returned at the end of the day to check out his claim.
I did find one breaker with signs of arcing on the stab behind it, but it was a pretty small spot - certainly not the entire bus bar. Someone had replaced one of the original Murrays with a Challenger brand breaker that had a different shape to the spring tabs which didn't grab the bus bar properly. The damage was slight enough that I actually had a pretty hard time seeing it with my LED flashlight. This breaker fed most of the lights, so it could definitely have given the tenant the impression that the whole apartment was going out. Nonetheless, it means I missed it. I allowed my troubleshooting and diagnosis to be lead by the suggestion of the real estate manager that the problem coincided with the POCO issues from a few weeks ago. I should have checked the breakers and bus for signs of problems but didn't. That's my bad and I own up to it.
What that diagnosis doesn't explain (and we're still waiting to hear back from the tenant) is that some of the lights he said were out were not on that breaker. We'll see how it goes from here.
I used to do a lot more troubleshooting than I do now. I see that I'm not as "in the groove" anymore and I made a stupid mistake. One of the good things about this forum is that it allows me to vicariously take part in jobs or problem solving that I don't normally face, so I figured I'd give something back with the example. I hope it helps someone
One last thing I'll mention - I'm a huge fan of my LED flashlight (Fenix TK35), but I wondered about not being able to see the discoloration on the bus bar with it. I could just barely see the pitting, but no discoloration. I know it's a cooler temp than an incandescent flashlight (probably about 6000K, so slightly blue, but not totally blue like the cheap LED flashlights), but I wonder if the color rendering is bad enough that it made the damage harder to see in spite of good, bright light. Anybody have any thoughts on this?
. I figured I'd analyze it here so others can learn from it too.Service call to check an apartment losing power intermittently. The property manager had had someone (unclear who...) check the meter and main breaker and claimed that it was all okay, so the problem must be in the apartment. I was called in to check inside the apartment by a real estate manager who is generally a pretty astute guy. He explained that the problems started a few weeks back when there were some repeated issues with HV lines feeding the complex - a car hit a pole bringing lines down, then a branch came down taking another section of lines down, with the POCO making several repairs in a few days/weeks time. Since then lights and receptacles would go off together at various times in multiple rooms. Tenant claimed that turning on the central AC would sometimes cause this, but it would also happen with AC off in the middle of the night. He seemed to think it happened more often in the evening when people were getting home from work. He had also noticed that the lights were dimming pretty often, but since he only has incandescent lamps in a few places (the rest are CFLs), he couldn't say whether it was throughout the apartment.
About three or four minutes into the interview with the tenant, the lights went out for maybe five seconds, then came back on. I went and got a few meters to check both legs, checked the breakers, they were cool, wiggled them around and tapped on them, which didn't cause any flickering or outage. There were no sizzling or crackling sounds from the panel. Voltage read steady on the main lugs although the lights did flicker very slightly from time to time. My setup only samples once per second for data logging, so it's possible I wouldn't see those dips.
I made arrangements to come back the next day when I could get to his main (in the electrical room) to check that out.
When the real estate guy called to make the arrangements the next day, the property manager took it upon himself to bring in another electrician to check the panel in the apartment. That guy claimed that multiple breakers and the bus bar were arc damaged and a panel change was in order. I returned at the end of the day to check out his claim.
I did find one breaker with signs of arcing on the stab behind it, but it was a pretty small spot - certainly not the entire bus bar. Someone had replaced one of the original Murrays with a Challenger brand breaker that had a different shape to the spring tabs which didn't grab the bus bar properly. The damage was slight enough that I actually had a pretty hard time seeing it with my LED flashlight. This breaker fed most of the lights, so it could definitely have given the tenant the impression that the whole apartment was going out. Nonetheless, it means I missed it. I allowed my troubleshooting and diagnosis to be lead by the suggestion of the real estate manager that the problem coincided with the POCO issues from a few weeks ago. I should have checked the breakers and bus for signs of problems but didn't. That's my bad and I own up to it.
What that diagnosis doesn't explain (and we're still waiting to hear back from the tenant) is that some of the lights he said were out were not on that breaker. We'll see how it goes from here.
I used to do a lot more troubleshooting than I do now. I see that I'm not as "in the groove" anymore and I made a stupid mistake. One of the good things about this forum is that it allows me to vicariously take part in jobs or problem solving that I don't normally face, so I figured I'd give something back with the example. I hope it helps someone
One last thing I'll mention - I'm a huge fan of my LED flashlight (Fenix TK35), but I wondered about not being able to see the discoloration on the bus bar with it. I could just barely see the pitting, but no discoloration. I know it's a cooler temp than an incandescent flashlight (probably about 6000K, so slightly blue, but not totally blue like the cheap LED flashlights), but I wonder if the color rendering is bad enough that it made the damage harder to see in spite of good, bright light. Anybody have any thoughts on this?
