What do I need to know about utility company coordination for ADU electrical?

Utility coordination is a separate process from your building permit, it's frequently underestimated, and on many ADU projects it ends up being the longest single item on the schedule. The key takeaway: start it when you start permitting, never when construction is wrapping up.

The typical sequence

1. Service request submission. You submit to the serving utility (PG&E, SCE, LADWP, SDG&E, or your local provider) with a site plan, electrical plans, and a load letter from a licensed electrician stating the calculated demand.
2. Utility engineering review. The utility evaluates whether existing infrastructure — transformer, service drop, meter — can carry the added load, or whether upgrades are needed.
3. Work order vs. service order determination. This is the pivotal step. A simple service order moves quickly; a work order requiring transformer or distribution upgrades can take much longer. Timelines vary widely by provider and scope, ranging from several weeks to many months.
4. Meter socket installation. A licensed electrician installs the meter equipment, which the building department then inspects.
5. Final connection and energization. The utility makes the final connection and turns the power on.

What drives the timeline

• Whether a new/separate meter is involved — separate service is far more involved than a shared subpanel.
• Whether a main service upgrade is needed — the utility must de-energize at the meter to perform it, which adds scheduling.
• Transformer capacity — if the neighborhood transformer can't carry the new load, the utility may need to upgrade it.
• Provider workload and regional policy — timelines differ significantly between PG&E, SCE, LADWP, and SDG&E.

Practical advice

Treat utility coordination as a critical-path activity. Submit your service request in parallel with your permit application so the two timelines overlap instead of stacking. A panel upgrade alone often runs 6–12 weeks of utility lead time, and separate-service work can stretch much longer.

A complete, professional electrical plan set with a clear load letter speeds utility review by giving their engineers exactly what they need. Our electrical plans include the panel schedule and Article 220 load calculation that support your service request. Requirements and timelines vary by utility — confirm specifics with your serving provider early.