The affected neighborhoods include St. George, Tompkinsville, Park Hill, Stapleton, Grant City, Fox Hills, New Dorp, Dongan Hills, Midland Beach and Rosebank.
Con Ed says the voltage was reduced to protect equipment and maintain service as crews work to repair the equipment.
The utility is asking customers in the affected areas not to use energy-intensive appliances like washers, dryers and air conditioners. Customers are asked to turn off lights and televisions when they are not needed.
The affected area includes over 61,000 metered customers and is bounded by Kill Van Kull on the north, Bard Avenue and Manor Road on the west, Raritan Bay on the south and The Narrows on the east.
Customers can report outages and check service restoration status by at http://www.conEd.com or by calling 1-800-75-CONED (1-800-752-6633).