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- Chris fills in the rest of the story told as a “Puzzler” in the last episode. Unfortunately none of the submissions won this week, possibly because the clues given were too obscure. The long and the short of the story is: my house isn’t haunted
The culprit (top) and the victim (bottom)
- Capacitive coupling lighting up LED lamps
- Phases in US vs Australia
- Reality tv producer setups
- Paul Zawada episode
- Buzzing components
- Predicting penny
- Enough about houses not blowing up, a Starship blew up! (on purpose, it seems)
- Chris read two books about space mining that he loved (2 part series…so far).
- Emerson Electric is buying National Instruments for 8.2B
- NI makes Labview, a popular test stand and automation software
- Dave has been choosing microcontrollers and did a recent PIC24 vs STM32 comparison
- Nordic just announced the nRF54H20, which is the successor to nRF52, nRF53…but also has a bunch of RISC V coprocessing cores.
Another fun image generated by Midjourney for show art this week…
Regarding your home electrical fault: Voltergeist! 🙂
(Technically, it’s called a sneak path. I actually diagnosed one of those years ago.)
I should add that in my case, the fault was one of the two 60-amp main fuses that had opened. The fuses were probably 50 years old, and I could find no evidence of a short circuit, so probably it was just fuse fatigue.
As for the device to monitor the power in your home. Not sure if there is a split phase residential version, but there is a 3 phase version called a phase monitor that will trigger a shunt trip if you lose a phase to prevent single phasing motors and other sensitive equipment.
So funny. While listening to you show I was at my friends house where we are trying to work the same problem.
Over here in Europe we have 3 Phase 380V (not split “in the middle”) but rather connected via a neutral STAR in the middle. So the outlet have each 220V towards the Neutral.
https://en.wikipedia.org/wiki/Three-phase_electric_power
Same problem: Stone in the Supply Wire cut the Neutral Phase. Every time a high current was drawn the voltage on that phase dropped and the lights went dim, while on the other phases the voltage went close to 380V (and very bright lights) since the current couldn’t run through the Neutral Supply, but went via Neutral to the next Phase.
That can happen on the North American split-phase system.
Without the neutral, the two ‘phases’ are in series and form a voltage divider across the 240 V. With a poor or missing neutral the voltages will ‘drift’ depending on the loading.
I found out about a loose connection when my UPS alarmed on a 140 V overvoltage when the kettle was turned on.
Guessed you had a phase down ! In Straya we generally only allow an appliance to use all threee phases, eg motors. However backin the day a two phase heater was a trap for young players!
Measuring your phases indvidually to ground at your mains supply point can let you know whats up.
Sometimes the supply distributor may have lost the phase, eg weather or event. IF one phase is down on the High Voltage the neutral point may move and then each LV mains supply phase can drift, One will go higher than 230VAC and one very low and the third will be in between, as the starpoint and phases and only being fed by two phases of HV in delta..
While there are GFCI breakers here in the US, what you more likely have in your load center are AFCI breakers. Since 2011 the NEC has required AFCI in family rooms, dining rooms, bedrooms, etc… and more recently even laundry rooms and kitchens.
Can confirm in Australia not all houses will necessarily go out. We had a tree take out a single phase in the street a few years back during a massive rainstorm. Took Ausgrid four days to get to it due to the volume of calls. We powered our fridge from the back neighbours with a long extension lead.
At least Chris probably saved a few dollars on his electric bill that month. 😉 Pretty neat how Dave zoomed in on the phase situation right at the start of this ghoulish tale.
If my father had known that the meter was only one phase he’d have tried to load as much of the house as possible onto the other. (50/50 that it would have ended very badly though.) He was just that much of a cheapskate.
Dave,
Older places in Oz can have 3 phase – Used to be used for the stove.
Typically 1 or 3 phases these days and most areas every 3 house will be on the same phase.
Yes it is possible and often happens that 1 or 2 phases will drop so some houses will be on and some will be off.