2 years after I quit fire equipt and started driving truck got a call from last employer. Had a new install fire alarm system that his tech could not clear the faults from the circuits on a new paint booth. Since he was a good boss and I had a week off before getting back in the truck I drove up to jax to give him a hand....No talk of compensation or anything ( knew him as a fair guy). Met him and his tech there, looked at the parts list, confirmed my assessment with a walk around. Sent him to home depot for 20 bucks worth of 4 gang, 1/2 inch extensions while went to grab breakfast bisquits.....30 min. after he got back was calling fire marshal for final inspection........that particular manufacturer changed parts suppliers and all the new sensors and audible/visual alarms were 2/3 of an inch longer and as a result when you screwed them into the box they would ground to the back of a regular 4 gang box.....tech had been there every day for 2 weeks trying to get it to work for inspection....saved the tech's job as I explained it took me and my suspervisor a week to figure it out 5 years before and it had been long enough that any service bulletins were basically non existant about it. Got breakfast and 500 for half a days work.