Phantom Trips

[tortuga]

Good questions, I'm sure. But given that L&I [state AHJ] has been out and not red-tagged anything, I assume the best. There are Series labels on the cabinets; I don't if L&I required them. I know the SqD fused disconnect was purchased to fulfill the series coordination requirement.

Your putting too much faith in the inspector.
They glance over the calcs the EOR or master (Administrator? they call it in WA?) signed and submitted for plan review (probably required a plan review on a 600 amp ) and see that someone calculated it, but they dont necessarily do more than that.

I know Square D QO breakrs have lots of documentation on the series rating combinations, but if the transformer numbers are correct, I seriously doubt any of that is needed as there is no way the fault current is very high at the disconnect.
The 600A disco could be for some other code purpose like the required outside main, or just so they could use 4 200A panels and call it a 600A service.

 

[tortuga]

Are the devices actually listed as rated as a Series Combination? What are the actual device model numbers? Has a time current coordination curve been developed to help understand problem? BTW: you cannot use series breakers if the the rated motor load on the panel exceeds 1% of the panel AIC rating.

https://download.schneider-electric.com/files?p_enDocType=Catalog&p_File_Name=0730CT9801.pdf&p_Doc_Ref=0730CT9801

 

[tortuga]

Sorry that might be a bad link here is another one

https://stevenengineering.com/Tech_Support/PDFs/45CBMCC.pdf

the 200A mains appear to be standard residential QOM2200VH

 

[Open Neutral]

The EC and PSE thought a serial rating was needed. We needed the main regardless. Just as on the previous house, I encouraged having a labeled EPO outside.

But I have an update. Last night I spoke with the owner. He reported that the 3 GSHP's in the Mech Room have disconnects, but surprising to me, they are not unfused "one-armed bandit" switches but rather a disconnect block you pull out. I always thought they were of poorer quality than the switch style.

He found the block on the one heat pump arcing. He pulled it out and reinstalled it but it fell halfway out again. So I suppose that might explain the panel and upstairs 200A mains tripping. We shall see.

The EC is due there today to replace it.