Sugarhouse power, from the woods to the canning floor.

What a sugarhouse needs, electrically

A working sugarhouse moves sap from the bush to the syrup pan through a chain of motors and sensors that all need to start, run, and shut down in roughly the same four-week window. The list, from the woods inward:

1. Tubing-vacuum pump in the sugarhouse, drawing sap on negative pressure from miles of plastic line. Typically 5–15 HP three-phase. The single largest electrical load in the building.
2. Sap transfer pump from the holding tank to the RO unit. Typically 1–3 HP single-phase, intermittent.
3. RO unit (reverse osmosis): a high-pressure feed pump (5–15 HP) plus auxiliary booster pumps and a control panel. Concentrates raw sap from ~2% sugar to 8–18% before the evaporator.
4. Concentrate transfer pump from RO to head tank. 1–2 HP single-phase, intermittent.
5. Head tank float — Class 2 wiring controlling the upstream feed pump. Failure mode: flood the evaporator or starve it.
6. Evaporator hood fans, two or four, drawing steam off the boil. 1/2 to 1.5 HP single-phase each.
7. Bake-out / draw-off on automated rigs: a small pump and PLC controller for syrup draw at 7.0° above water-boil.
8. Lighting — bright over the canning area, dimmable over the boil so the sugarmaker can read the surface.
9. Heat trace on the perimeter sap line for late-March mornings below freezing.
10. Sap-line monitoring if the bush has electronic vacuum sensors. Class 2 home-runs back to a control panel.

What's included on a J-03

• 240V three-phase or 240V single-phase feeders to all motors, properly fused per NEC Article 430.
• Soft-start on every motor > 5 HP. See the March almanac on why this matters across the rural feeder.
• GFCI on all 120V receptacles in the sugarhouse, milkhouse, and washroom areas (NEC 547).
• Type-1 SPD at the service entrance; Type-2 at the equipment panel.
• Class 2 wiring for head-tank floats, RO panel I/O, and bake-out controllers.
• Bonding of all stainless equipment frames to a #4 copper bus tied to the building grounding electrode system.
• Lighting: typically LED high-bay over the boil, LED panels with dimming over canning.
• Heat trace control and contactors for the sap-line perimeter.
• Permit at VT DFS.

What's not included

• The evaporator, the RO unit, and the vacuum pump themselves. We coordinate with Leader Evaporator, CDL, and Lapierre; they ship the manufacturer's panel; we wire the building.
• The plumbing of the sap and concentrate transfers.
• The wood-shed or oil-fuel side of the evaporator. Electrical to the burner control panel only.
• Bottling-line equipment. Quoted separately as J-08 with its own NEC 422 review.

The four-week problem

A 5,000-tap sugarbush draws 28 to 42 kWh per day during the run. The same sugarhouse draws less than 4 kWh per day for the other 47 weeks of the year — about as much as a freezer and the lights. So the conductor sizing, transformer sizing, and panel sizing are all controlled by a four-week peak that only happens if the weather cooperates.

Two implications. First, we don't size for "average" — we size for the day when every motor is running and the boil is going hard. Second, we set the heat-trace contactor to drop out at 35°F so the perimeter trace doesn't keep running all summer. Sugarhouses where the previous electrician left the heat trace on a thermostat have, on average, run 700 unnecessary kWh per year for the last fifteen years before someone notices.

Price band

Project	Typical low	Typical median	Typical high
Hood & lighting refresh on existing rig	$1,200	$2,400	$4,500
RO unit retrofit (new RO, existing 240V available)	$3,800	$6,200	$10,500
New evaporator wiring (4×12 or 4×14)	$5,800	$8,400	$13,200
New sugarhouse build (full electrical)	$18,500	$28,000	$42,000

Sugarhouse jobs nearly always pair with a J-01 service upgrade if the existing service is < 200A. The realistic minimum for a working 1,000-tap sugarhouse with RO is 200A residential single-phase; for 5,000 taps with vacuum and RO, plan on 400A or three-phase 600A.

Related

For a worked example, see East Craftsbury sugarhouse evaporator wiring (November 2025). For why your sugarhouse vacuum pump trips when the next farm down the line starts theirs, see March: Sap-run power quality on the rural feeder.