Engineers from the various agencies wanted to see for themselves the equipment at Candlestick, for instance a switcher that controls the current into the stadium. There are also seven or eight substations they wanted to see.
"We've done infrastructure upgrades throughout the years out there, so we really won't know till we finish our walkthrough and checking all the equipment," Rec and Park Operations Director Dennis Kern said.
Also Wednesday, city crews were out repairing the collateral damage from the outages. Some of the fire alarm boxes near the stadium were fried. Other crews fixed the wiring of street lamps around Candlestick which were no longer working.
There were two outages Monday night during the nationally televised game between the 49ers and the Pittsburgh Steelers.
The first happened at 5:18 p.m. The downed power line could be seen on TV arcing northwest of Candlestick. Tens of thousands of fans sat in the dark for 20 minutes before the lights came back on. The stadium went black again in the second quarter at 6:43 p.m. It took 16 minutes to bring back the lights.
PG&E traced the cause of the first blackout to a downed power line which fell from a utility pole. A splice in that line which connects two electrical wires failed, shutting power off to the stadium.
"We all have a clear understanding of what happened with the first outage, PG&E's line failed; the second outage is less clear," SFPUC Asst. General Manager Barbara Hale said.
In fact, the second power failure is still a total mystery. It appears now that it was a partial outage.
"It appears there may have been some pockets in the park that did not get grid power right away and were still on backup power," Hale said.
After dark, city crews and engineers will test the lights. They want to ensure they are repaired as soon as possible, certainly before any playoff game.