What electrical and rough-in requirements apply to hardwired dispensers?
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Hardwired Dispenser Electrical Rough-In
Hardwired dispensers usually receive low voltage from an approved transformer. Rough-in must coordinate power, countertop openings, undercounter equipment, plumbing, accessibility and service.
Branch Power
Common North American input.
Dispenser Side
Often 6, 9 or 12 VDC.
Protection
As required by code or manufacturer.
Power Arrangement
“Hardwired” may mean a plug-in adapter, remote transformer or permanent power unit. Identify the exact method.
Key Rules
- Never connect line voltage to a low-voltage sensor.
- Use listed transformers and connectors.
- Keep receptacles serviceable but hidden from users.
- Protect wiring from leaks and damage.
Typical Rough-In Data
| Item | Coordinate |
|---|---|
| Deck opening | Model-specific size |
| Counter | Maximum thickness |
| Power | Voltage and GFCI |
| Clearance | Reservoir and controls |
| Access | Repair and removal |
Countertop and Undercounter Coordination
Confirm the model before drilling. Many deck units use openings near 1⅜ inches, while top-fill ports can be larger. Verify faucet spacing, sensor clearance, deck thickness and underside layout.
Accessibility: Transformers, reservoirs and wiring must not intrude into required knee and toe clearance.
Service Space
Keep boxes and reservoirs clear of traps and leak points. Provide access for replacement without dismantling the lavatory.
Specification
Provide dispensers with approved AC or hardwired assemblies. Supply branch power, GFCI protection, boxes, transformers and low-voltage wiring per code, listing and manufacturer instructions. Coordinate deck holes, counter thickness, spacing, reservoirs, tubing, wiring, plumbing and accessibility before fabrication.
Commissioning
Verify voltage, GFCI, transformer, connections, priming, sensor response, dose consistency and leak-free operation.
FAQ
Does the dispenser receive 120 volts directly?
Usually not. Line voltage normally feeds a low-voltage transformer.
Can one transformer power several units?
Only through an approved distribution system.
