Crews were out in force Wednesday, working to restore power to the more than 2.5 million New Jersey homes and businesses where electric service was knocked out by Hurricane Sandy.

It's proving to be a slow process.

About 900,000 of the 1.5 million Public Service Electric and Gas Company customers who lost power were still without electricity Wednesday afternoon. A Jersey Central Power and Light representative says the power is back on for about 150,000 of its 1 million customers who lost service.

The transmission system and substations need to be repaired before crews get to the power lines in neighborhoods, according to Ron Marano, a JCP&L spokesman.

"One of the most common things we get from people, they're frustrated, they may have a pole-top transformer on their street that needs to be replaced or repaired," he said. "But if we replace that or repair that and we didn't have the problem corrected at the feeder line or the substation, they'd have no power."

Morano says helicopters are surveying damage to substations and 1,200 forestry crews are clearing trees so the company can get access to its facilities. He's not sure when all customers will have their power restored.