"You need a new 10k breaker panel" - Me: maybe not.

[cashnocredit]

The electricity shut off at mid-day when it was about 100F outside. So I went out to check the breakers. They appeared OK. We have a "smart meter" since we have PV's installed. No way to turn off the power going to the breaker panel which I found weird. The smart meter is behind a second panel that has a SDGE tie on it to prevent anyone from opening it except SDGE personnel. So called SDGE about the power outage. Service person showed up and found the main breaker had tripped (which I'd missed) and suggested we should replace the whole panel. My wife had been talking to a neighbor that had recently gotten a panel upgrade to fast charge her EVs so she got a reference.

 

Called the reference who came out and suggested a new panel. Cost about 10k.

 

I looked up the breaker (225 amp) part number and bought a replacement for just under $200. 

 

I had to change the breaker "hot" since there was no way to turn off the power w/o calling SDGE back and scheduling a turn-off that would take a 3 week delay. Fairly simple and safe even though the incoming wires are hot. Checked the current and voltage drop across the new breaker and it was just a few mVs with about 60 amps load. No reason I could see to change the panel. We aren't planning to get EVs let alone fast chargers.

[greendeh]

@cashnocredit

Thumbs up for an inexpensive repair. Fun game of Operation with the "buzzer" being a tad more real.

 

Question though is "What makes a 225 amp main breaker trip without tripping any of the smaller breakers?"

Not looking for a reply, just giving you that question to keep in mind.

 

[cashnocredit]

2 hours ago, greendeh said:

@cashnocredit

Thumbs up for an inexpensive repair. Fun game of Operation with the "buzzer" being a tad more real.

 

Question though is "What makes a 225 amp main breaker trip without tripping any of the smaller breakers?"

Not looking for a reply, just giving you that question to keep in mind.

 

After I swapped it out I examined the old breaker. The problem turned out to be a poor contact on one side of the leaf sliders internal to the breaker. This produced a high resistivity contact that, over time, caused the breaker to heat up enough that it tripped at low current (about 25% of rating). It was one of the very hot days (99F) where the ACs were running. My current probe indicated that it was tripping with only about 50 Amps. Breakers operate by a combination of heat and current sense.

[StarkRaven$]

I’m impressed that you can do that.

[greendeh]

On 9/19/2024 at 11:15 AM, cashnocredit said:

After I swapped it out I examined the old breaker. The problem turned out to be a poor contact on one side of the leaf sliders internal to the breaker. This produced a high resistivity contact that, over time, caused the breaker to heat up enough that it tripped at low current (about 25% of rating). It was one of the very hot days (99F) where the ACs were running. My current probe indicated that it was tripping with only about 50 Amps. Breakers operate by a combination of heat and current sense.

 

I am glad you were able to diagnosis the "why"