Do I need temporary power to build my ADU?

Usually, yes, and there are two common ways to get it: a temporary service from the utility on a meter pole or post, or a permitted temporary circuit from the existing house. Article 590 of the California Electrical Code allows temporary wiring during construction, requires GFCI protection for the receptacles workers use, and requires the temporary wiring to come out when the work is done.

Option 1: Temporary service from the utility

PG&E notes that construction projects may need temporary electric service to poles or posts. The typical steps are:

1. Apply to your utility for temporary service.
2. Your contractor installs the temporary meter panel and pole or post in a spot protected from hazards and vehicle traffic.
3. Your local building department inspects it.
4. The utility energizes it. PG&E states that only its employees or authorized contractors may connect or disconnect service.

SCE, SDG&E, LADWP and SMUD have their own temporary service procedures, so check with the utility serving your property.

Option 2: Power from the existing house

On a backyard ADU, construction power can come from the main house. That can mean a temporary circuit from the house panel, or installing the permanent ADU feeder early and using a temporary panel or outlets at the ADU end. Either way it needs to be permitted and inspected, and it draws on the same service the house is using, so saws, heaters and compressors running alongside normal household use can trip the main breaker.

Rules for temporary wiring

• Time limits. Section 590.3 permits temporary power during construction, remodeling, repair or demolition, and requires it to be removed immediately once construction is complete.
• GFCI. Section 590.6 requires GFCI protection for 125-volt, single-phase, 15-, 20- and 30-amp receptacles that aren't part of the permanent wiring and are used by workers, and for permanent receptacles that are being used for construction power.
• Still real wiring. Temporary wiring has to be properly grounded and protected, just like permanent wiring.

Plan the temporary setup around the permanent one

Put the temporary pole where it won't block the permanent trench, the meter location or the ADU foundation. If the ADU will get its own service, coordinate the temporary and permanent requests with your utility at the same time.

What this means for your electrical plan

Temporary power is often arranged by your contractor rather than drawn on the permit plans, but the plan's site layout, feeder route and meter location show where a temporary setup won't get in the way. Ask your building department how it permits temporary power. See utility coordination for ADU electrical, how the ADU permit process works and our ADU electrical guide.

Sources: pge.com, dgs.ca.gov, ecmweb.com.