Getting different answers from different inspectors. On a new commercial DWV system (4" PVC schedule 40, horizontal runs, no pressure application — gravity drain system), one AHJ wants 10 PSI hydrosta...
School question (sorry if this is basic). We're covering braking systems this week and the instructor talked about brake fade on descending grades. He said drum brakes are more prone to fade than disc...
Running into intermittent startup failures on a commercial install. 40x Meanwell HLG-240H-C700B LED drivers on a single 20A circuit at 277V. Panel schedule shows Circuit 14 — all drivers wired parall...
Posting this because it took me longer than it should have and the technique is worth sharing. 2017 Transit, intermittent loss of communication with the ABS and instrument cluster, U0121 and U0155 st...
University lecture hall, twenty years of accumulated AV in one rack. Rebuilt it over a semester break. What I changed structurally, not just cosmetically: **Horizontal lacing bars instead of D-rings...
Recurring conversation and I want to compare approaches. Customer wants whole home backup. House has a 5 ton single stage AC with an LRA of 88A, an electric range, an electric dryer and a well pump. ...
Still learning refrigeration theory in school. We've been taught that TXV systems should be charged by subcooling, not superheat. But my instructor also said superheat tells you about evaporator perfo...
This is a real question, not a gotcha. I was POCO for 30 years and I watched every utility meter tech torque their connections religiously. Now as a contractor I see JWs who never touch a torque screw...
24kW ground mount, driven pier foundation, installed two years ago on a site with expansive clay that I did not adequately account for. What happened: seasonal movement of roughly an inch and a half ...
Not testing yet myself but my school is teaching to the 2026 and there are a fair number of changes I am struggling to keep straight, particularly around GFCI expansion and the energy storage articles...
Pricing out an AV upgrade for a university, 12 conference rooms, existing Cat6A infrastructure. Currently they have HDMI over HDBaseT in each room (3rd party, failing). Option A: Crestron DM-NVX enco...
Trying to get better at giving customers a clear decision framework for transmission work. Right now I kind of wing it based on symptoms and mileage, which isn't great for customer communication. Wha...
Installed a Tesla Powerwall 2 with Backup Gateway 2 last month. Works great during normal grid operation — charges from solar and discharges per the set schedule. During a grid outage test, the Power...