I stopped by the site a few hours after WNB took pics. The curbs around the transformer pads were formed up and
Utility lateral ducts (conduit from SDGE to transformer locations) are in, so it doesn't seem that any more major trenching will be necessary.
Crew very friendly, laughed and told me they'd never worked on such a highly anticipated project.
They predicted completion in mid-May.
A quick note on what may seem glacial construction progress: the work crews do not set the overall pace.
They are not on site every day. Their managers will mostly only send them to the site when there is enough work to justify sending a crew for a day or more. In between, it may seem that nothing is happening - the contractor and crews have probably gone as far as they can and will not return until some additional element has been completed by another player in the process - an inspection or permit that must be approved/completed by Tesla, a lender, the city, the county, state or utility before the next phase may proceed. The State and Federal governments are involved in these projects (rebates, subsidies etc), so there is a complicated process of control and approvals happening off-site that largely dictates the project's pace.
The crews and their bosses would probably like nothing better than to crank through the job with a few weeks of constant activity.