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Discussion Starter · #3 ·
GEORGE D said:
Ok just got home from [email protected]&$ing warranty run. Replaced a panel this afternoon and got a call at 10:00pm, " whole house is out"...what do you mean I say...."everything is off". So long story short the main 100 tripped, I explained to shut off all breakers and reset main, then bring up all others. I stayed On the phone with him for several minutes, explaining that he MUST turn breaker off first to get it on. After several attempts he says it won't turn off, so I'm thinking great, f)$&&cking main took a dump. Soon as I arrive (45 min drive), I do exactly what I told him to do, breaker turns off and on no problem. Anyhow, I discovered that the 40 amp AC disconnect breaker was also tripped after realizing the ac never came on when I reenergized panel. With that said, I went ahead and measured amps on ac which running was around 19, start up exceeded 100, is that an expected lock-rotor draw? It seemed to hold for at least 1-1.5 seconds at 100. My thoughts are that the older breaker in disconnect may have a close trip setting as newer 100 amp (completely guessing), or is it possible that when the over current caused the disconnect breaker to open that as the contacts pulled apart the inrush current possibly triggered main? What are y'all's thoughts, oh and by the way the before I changed this panel an HVAC tech had come because ac didn't work, he discovered burned up breaker as well as other breakers. He replaced his and got it up and running. I found multiple burned breakers which recommended replacement.
 

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Sorry, that's the only way to see what I'm typing, having to quote something first. How annoying, why hasn't that been fixed by the way.

Have you tried to hit post preview.?


Also if you are on an iPhone / iPad you cane post from the full site.

Here is the link ,,,,,give it a shot..

I'm posting from my iPad and the regular site is much better..:thumbup:
 

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check ac compressor. seems really high for it draw that many amps on start up. I would be leary of the ac unit. since it all ready had a burnt breaker in the old panel
 

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Ok just got home from [email protected]&$ing warranty run. Replaced a panel this afternoon and got a call at 10:00pm, " whole house is out"...what do you mean I say...."everything is off". So long story short the main 100 tripped, I explained to shut off all breakers and reset main, then bring up all others. I stayed On the phone with him for several minutes, explaining that he MUST turn breaker off first to get it on. After several attempts he says it won't turn off, so I'm thinking great, f)$&&cking main took a dump. Soon as I arrive (45 min drive), I do exactly what I told him to do, breaker turns off and on no problem. Anyhow, I discovered that the 40 amp AC disconnect breaker was also tripped after realizing the ac never came on when I reenergized panel. With that said, I went ahead and measured amps on ac which running was around 19, start up exceeded 100, is that an expected lock-rotor draw? It seemed to hold for at least 1-1.5 seconds at 100. My thoughts are that the older breaker in disconnect may have a close trip setting as newer 100 amp (completely guessing), or is it possible that when the over current caused the disconnect breaker to open that as the contacts pulled apart the inrush current possibly triggered main? What are y'all's thoughts, oh and by the way the before I changed this panel an HVAC tech had come because ac didn't work, he discovered burned up breaker as well as other breakers. He replaced his and got it up and running. I found multiple burned breakers which recommended replacement.
With just a 100 amp service and over 100 amp inrush current that can blow the main IMO.

They should have upgraded with the AC...
 

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But harry the ac guy probably threw his gauges on it. Added gas til it was beer can cold and said there you go its fine :thumbup:
 

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If that A/C unit run 19 amps normally but start at 100 amp that is pretty high IMO but it will be wise to get the HVAC contractor to come out and check the unit ( if this unit is older one it pretty much done for it ) some case starting capaitour is done for it.

Merci,
Marc
 

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What's the available fault current on this project?

I've seen instances where the main trips out before the branch circuit breaker due to high available fault current ....

:blink:
 

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The 100 amp main should handle somewhere between 400-1000 amps inrush for instantaneous trips.
 

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100 amp LRA(inrush current) seems reasonable to me. 1-1.5 seconds at LRA seems a little long. Have the HVAC guy check or install a hard start kit if everything else is working properly.
 

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I think that new uncoordinated main saved the whole system.

Lock rotor should be printed on the units label. 300% of RLA should be about right.
or,
Just keep resetting the breaker until the compressor blows a hole out of the side if itself.
Instant vindication.
 

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Discussion Starter · #15 ·
Yeah I advised to have an HVAC guy come evaluate the unit better, and if I know HVAC contractors they will definitely push for a new system, especially considering this one is old.
 
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