Homestead · built first
The hub
The first building, whose wood plant heats every other: three shipping containers under one timber roof, holding the boilers and the tank, the water and the power, a bathroom and a small kitchen, with a covered works between them and the woodshed under the roof carried down on the south.
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The plant, the south container: a gasification wood boiler loaded through a door from the woodshed, one 1,000-gallon storage tank, a propane boiler, the headers and the pumps. The lines to every building leave it in one buried trench. Water, power and people, the north container: two stainless reservoirs, the panels, the inverter and the battery, a small kitchen and a bathroom. The stores close the west end against the winter wind and the afternoon sun, their side doors opening into the court.
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One roof over all of it at 6/12, the ties at +14'-6", so a truck or a tractor fits under them. The court is left cold, open to the east and closed to the west. The south slope carries on down over the woodshed, where the wood dries in the sun, and carries the solar array east of the chimney, on rails clamped to the roof's standing seams.
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A Wood Gun SE210, 155,800 Btu/h in its EPA certification, loaded from its east face with the woodshed's door in front of it, about a million Btu a load. One 1,000-gallon ASME tank in 4 in of mineral wool holds ~810,000 Btu between 190 and 100 °F. Two Lochinvar Knights on propane, each vented in stainless steel, heat only the tank's top third. The tank and the boiler stand on piers of their own through the container's floor: the containers carry nothing heavy.
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Two 1,000-gallon stainless cisterns filled from the well through an air gap, a booster, the treatment and the hub's own hot-water tank; the panels, a hybrid inverter and the battery; a kitchen and a bath, each opening from the court. Radiators keep the water room from ever freezing.
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Wood leads, propane follows, then the element, each below a lower setpoint. On a −25 °F day the site wants ~7.4 million Btu, about 7 loads of wood; the two propane boilers together carry ~288,000 Btu/h, the whole design night. If the power fails mid-burn, the pumps run on the battery and a gravity dump over the boiler takes 10 % of its output, as its manual asks.
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The reservoirs are piped in series so the water keeps moving through them; the hydrant and a fire hose draw before the treatment, 2,000 gallons at 25 gpm for about 80 minutes. The well stands well clear of the septic tank and its field, as the well code asks.
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About 12 kW of panels on the south slope and a 32 kWh battery, under the fire code's limit for a utility room, behind a hybrid inverter that starts the well pump. The battery carries the heat plant, the water and the house's critical circuits for about 36 hours of a winter outage; the panels and a generator inlet carry it longer.
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One trench from the plant to the workshop: the water below frost, the heat line above it, the power and fibre conduits above that. The heat line is the one plastic kept here: PEX inside its jacket, with no warranted alternative.
The hub's power in three places: the meter and main disconnect outside the north wall; the main panel in the power room, on the grid's side, with the feeders and the loads that wait out an outage; and the hub panel behind the Sol-Ark, which the battery carries. The 2023 NEC, Wisconsin's since 1 September 2026. Copper THHN in EMT inside the boxes, 12 AWG the least; the feeders aluminium XHHW-2 in the trench's conduits. VA is the load calculation's figure, not a meter reading; the makers' figures are from their manuals, the rest marked est.
Hub panel, behind the inverter: 200 A bus, 40 spaces
| Ckt | Load | Where | Breaker | Wire | VA | Leg |
|---|---|---|---|---|---|---|
| 1, 3 | Well pump, 1 hp, 240 V: its controller on the reservoirs' level switches | water | 20 A 2P | 12 Cu | 1,920 | A, B |
| 2, 4 | Booster, ¾ hp, 240 V (est.) | water | 20 A 2P | 12 Cu | 1,656 | A, B |
| 5 | The works: receptacles on the posts, GFCI (est. 6) | court | 20 A 1P | 12 Cu | 1,080 | A |
| 6 | Water and power rooms: lights, receptacles | water, power | 20 A 1P | 12 Cu | 760 | A |
| 7 | Wood Gun SE210: draft fan, controls, the loading unit's pump, the dump valve | plant | 20 A 1P | 12 Cu | 900 | B |
| 8 | The plant's lights and receptacles | plant | 20 A 1P | 12 Cu | 760 | B |
| 9 | Counter receptacles, east, GFCI | kitchen | 20 A 1P | 12 Cu | 720 | A |
| 10 | The works: lights under the trusses (est. 6 × 100 W LED) | court | 20 A 1P | 12 Cu | 600 | A |
| 11 | Counter receptacles, west, GFCI | kitchen | 20 A 1P | 12 Cu | 720 | B |
| 12 | Refrigerator | kitchen | 20 A 1P | 12 Cu | 600 | B |
| 13 | TL-1044 at its pad: blower, controls; a disconnect at the unit | outdoors, the pad | 15 A 1P | 12 Cu | 1,150 | A |
| 14 | The loop's pump: the yard's line to the garage, the starter, the workshop and the house (est.) | plant | 15 A 1P | 12 Cu | 400 | A |
| 15 | Bath receptacles, GFCI | bath | 20 A 1P | 12 Cu | 360 | B |
| 16 | Knight WHB155, the first, and its boiler pump | plant | 15 A 1P | 12 Cu | 500 | B |
| 17 | Hyprotherm tie: glycol pump, tank-side pump, its differential control | plant | 15 A 1P | 12 Cu | 400 | A |
| 18 | The woodshed's and the doors' lights | outside | 15 A 1P | 12 Cu | 300 | A |
| 19 | Knight WHB155, the second, and its boiler pump | plant | 15 A 1P | 12 Cu | 500 | B |
| 20 | The farm's and the north garage's pumps (est.) | plant | 15 A 1P | 12 Cu | 400 | B |
| 21 | Treatment: UV, the softener's head | water | 15 A 1P | 12 Cu | 150 | A |
| 22 | Heat cable on the well line's riser through the skirt, GFPE (NEC 427) | water | 15 A 1P | 12 Cu | 60 | A |
| 23 | Kitchen and bath: lights, the hood, the bath fan | kitchen, bath | 15 A 1P | 12 Cu | 400 | B |
| 24 | The hub loop's pump; the works' floor pump later | plant | 15 A 1P | 12 Cu | 250 | B |
| 27 | The plant's controls: the tank's controller, the Knights' sequencer, contactor coils | plant | 15 A 1P | 12 Cu | 150 | B |
| 28 | Network: the fibre's terminal, the router, the switch | power | 15 A 1P | 12 Cu | 150 | B |
Legs: A 7,408 VA, B 7,478 VA. Calculated load (NEC 220; a hub is not a dwelling): 16,681 VA, 70 A at 240 V. It is fed from the Sol-Ark's load terminals through the inverter's own 200-A breaker, so the bus and the 3/0 Cu to it are rated 200 A; the grid reaches it through a 100-A breaker in the main panel (3 Cu). The grid's 100 A and the inverter's 62.5 A × 1.25 make 178 A against the bus's 240 A (705.12(B)(3)(2)). 6 spaces are left empty.
Main panel, the grid's side: 400 A bus, 20 spaces
| Ckt | Load | Where | Breaker | Wire | VA | Leg |
|---|---|---|---|---|---|---|
| 1, 3 | Farm feeder, ~193 ft | feeder | 200 A 2P | the feeders | pending | A, B |
| 2, 4 | The Sol-Ark 15K's grid port: the hub panel through it | power | 100 A 2P | 3 Cu | 16,681 | A, B |
| 5, 7 | The tank's element, 9 kW, on its controller's contactor | plant | 50 A 2P | 8 Cu | 9,000 | A, B |
| 6, 8 | The works' 240-V receptacle, NEMA 6-50: the welder, the compressor (est.) | court | 50 A 2P | 8 Cu | 6,000 | A, B |
| 9, 11 | Cooktop, 30-in induction (est. 7.4 kW; NEC 220.55 counts 8 kW) | kitchen | 40 A 2P | 8 Cu | 8,000 | A, B |
The cooktop, the element and the welder are on this side on purpose. In an outage they are off, so they can never trip the inverter while it carries the boilers' pumps; on the generator the same holds, since the generator feeds the hub panel only. The cost: no cooking in the hub on the battery or the generator.
The feeders
| To | Breaker | Run | Conductors | Drop |
|---|---|---|---|---|
| Farm | 200 A 2P | ~193 ft | 250 Al | 2.2 % at 160 A |
Sized by Table 310.16 at 75 °C, then up until the drop is 3 % or less at 80 % of the breaker (est.: the farm has no load calculation yet). The run: the power room along the hub's west wall and out with the farm's lines to its panel, 25 ft inside (est.). A conductor upsized for the drop takes a larger equipment ground in proportion (250.122(B)). The house and the workshop have a service of their own off the road, so the hub feeds only the farm; their own panels and their backup in an outage are still to draw.
The checks
| A cold night, the grid down: all of the hub panel's loads that would run | 5,140 W; the Sol-Ark gives 12,000 W on the battery alone |
| The well pump starting on top of that (48.7 A locked rotor) | 15,618 VA; it gives 24,000 VA for 10 s |
| The Sol-Ark feeding back into the main panel's 400-A bus, at the end away from its feed (705.12(B)(3)(2)) | 478 A against 480 A: just |
The well pump and the booster are interlocked so they never start together. The dump valve shares the wood boiler's circuit, so a tripped breaker opens it as a power failure does. The two Knights each have a circuit of their own, so one breaker can stop only one boiler. The service's size waits on the farm's own load calculation (U7).
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Three places for the power: the meter and main disconnect outside, the main panel on the grid's side with the feeders and the loads that wait out an outage, and the hub panel behind the inverter, which the battery carries. The cooktop, the tank's element and the welder's outlet stay on the grid's side, so an outage can never overload the inverter while it runs the boilers' pumps. Each feeder is sized for its voltage drop over its run.
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Copper for the water, cast iron for every drain and vent. The containers stand on piers over a skirted, unheated gap, so every trap and every water line stays inside the warm box: the shower sits on a raised base, and each fixture drains straight down through the floor to a buried drain that runs on to the septic tank, bent clear of the piers.
Why it comes first
- Boilers are noisy and don't belong in a house. Everything that burns lives here, beside the tank, away from where people live and work; no propane ever enters the house or the workshop.
- It serves the build. With the well, the septic and the power, it gives the crew heat, water, a bathroom and a kitchen on the site from the first day, and a covered works to outfit the bunkers' containers in.
- It serves every building after. Each takes its own buried branch and keeps a small hot-water tank of its own, so its taps run hot at once.
- To settle with the installers: the storage tank's stamp at its working pressure; the propane tank to its supplier's setbacks; the treatment, from the water test.