Hot take: a brownout during a 4-zone panel swap in Tucson fried my tester and taught me to check voltage first | Alarm System Installers - Opinions Matter
Ever think about how many guys skip that step because the meter says 240 and they figure it's fine? That drop from a brownout is sneaky, it'll read normal one second and tank the next. I check at the panel and at the outlet now, not just one spot.