dorky impossible situation

good day experts…looking for some emergency info. my daughter is selling her house and has to be out in two days , suddenly sewer quit working so now amongst other things the electrical inspector (since we did some electric work was there) said that there has to be an arc fault on the hard wired smoke/co alarms which by bad fortune is also wired to the lift station and when every it starts up it trips the arc fault. electrician (surprisingly) said you can remove the arc fault and reinstall regular breaker and hope the inspector (coming at 4:30 today) doesnt see it…or find where the alarms are connected and run a new circuit for them. thats pretty tough, would include cutting into walls. this seems unreasonable, im wondering if its one of those deals where if its there, ok…but new construction requires the arc fault. i have considered disconnecting the hard wired alarms and just putting battery operated in, but that would tick off the buyer. really!!? we have to do this?
mike, frustrated in mn

Whatever the AHJ says is what you have to do. At the end of the day he is the one that signs off on the work.

IMO, hardwired are preferred due to them being interconnected to sound off when triggered. Downside is… when the power goes out, they are dead in the water. Many do not have battery backup. My recommendation is to replace them with the new Bluetooth enabled, interconnected, 10yr lithium battery powered units. Solves all problems and a lot cheaper and faster than the alternative. (AHJ pending approval, of course).

https://dps.mn.gov/divisions/sfm/document-library/Documents/Fire%20Code%20Information%20Sheets/SmokeAlarmsResidentialReqInfoSheet.pdf

https://www.revisor.mn.gov/statutes/?id=299F.362

Correct, but quite often the AHJ needs to be made aware of alternative methods to the same end result… done politely of course.

but the problem is, the sewer system was working find before without an arc fault, now there is a nonworking lift pump two days before move out. and a situation which appears to include cutting into walls to run separate circuits for pump and for alarms. just seems like something that would be grand fathered but required on new construction

If the house was built prior to 2002 AND your electrical work did not involve these circuits, you wouldn’t typically be required to upgrade the circuit to AFCI (i.e., it would typically be grandfathered). If it was later than 2002 and / or your work did involve those circuits, I would expect them to require the upgrade. Of course each municipality can make up their own rules, provided they are not superseded by state law.