About half a year ago I bought a used UPS. It didn’t have enough output to power my main PC, but it’s perfect for my home server and network.
Starting on Christmas eve and continuing even today, my neighbourhood has been getting intermittent brownouts. It’s only affecting one phase (house is on a three-phase 240V connection), which happens to be the one powering my network (also all of the light fixtures, stupid Soviet house), and the UPS works beautifully. I didn’t lose any of my services even once. Without it, I would probably be reinstalling Proxmox and praying to the RAID gods to restore my hard drives.
“It pays for itself as soon as it is needed” is proven true once again.
It’s more common than you think. Most European households use split three-phase power. The grid provides three live wires (50Hz AC phase-shifted by 120°) and a neutral. The voltage between any live wire and the neutral is around 230V, and between any two lives is ~380-400V. Residential power circuits are connected to a live and neutral wire, each of the circuits being fed by a different phase, with separate safety devices (ground fault interruptors and such).
North American residential power is different, but also uses split phases. The transformer that connects the residence to the grid steps the voltage down to 240V, but has a center tap that is used as the neutral wire, resulting in two 120V phases 180° apart from each other. 120V goes to small appliance circuits, and 240V feeds large appliances like HVAC and electric stoves. You can listen to Brown Jacket Man explain it in detail.
Another important note is that transformers supply entire neighbourhoods (dozens or hundreds of households) instead of individual residences.
Oh shit, thats super cool, I know a bit about the US power grid since that’s where I live, but all I knew about the European power grid is that like most of the world they have 240V AC instead of 120 like most outlets provide here in the US (even though we technically also have 240v and just use it for like ovens and electric dryer machines)
Thank you for teaching me stuff, I had no idea three phase power is so common elsewhere!
(Also fuck yeah, technology connections, I love that guy!)
Except Norway, where 3-phase IT is still dominant. TN is only being built in newly established buildings/areas.
IT being phase/phase = 230V, with no neutral wire.
Upside is it being more robust to ground faults, but you lose 11/22 kW possibility on EV chargers. 7,2 kW is max (32A @ 230V).
Looking forward to it being gone, tbh…
In Belgium it’s still widely deployed. Two other downsides are the risk of electrocution with monopolar switches (can’t rely on a light switch, not that you ever should but lots of people think “no light = no zappy zappies” then get a nasty surprise), and compatibility issues with some 3-phase appliances that aren’t designed to be hooked up without a neutral because they were not sold in an area where 3x230 is common.