Consolidated Edison Inc. and the union representing its employees have resumed their negotiations.
Con Edison, which has over 3 million customers, declined to characterize the talks on Friday.
However, a spokesman for the Utility Workers Local 1-2 said the situation was grim.
The bargaining continued for more than nine hours on Thursday.
The National Weather Service says the temperature could hit 100 on Saturday. Heat waves tend to put a strain on electrical systems.
Con Edison has been using managers in the field.
Spokesman Michael Clendenin says the utility is ready to respond to any emergencies. He says there have been few customer complaints.
Con Edison has announced energy saving tips to its customers to help reduce usage over the weekend.