The utility serves about 675,000 customers in the state and filed the rate request late Friday with state regulators.
The increase, amounting to about $50 a year for the average electric customer, will help cover the $70 million in construction costs during the past year for the new reactors at the V.C. Summer nuclear in Fairfield County near Columbia.
SCE&G and the state-owned electric utility Santee Cooper are building the reactors that will cost nearly $10 billion. The first reactor is expected to come online around the end of 2017 and the second the following year.
If approved, the rate increase would take effect in October and be the seventh under the state's Base Load Review law was passed eight years ago by the General Assembly. Under the law, the utility can raise rates to pay for construction of the nuclear plants before they go into operation.
The latest request, if approved, will mean customers will be paying about $20 more per month for their power than they were at the beginning of 2009.
SCE&G says that paying construction finance costs while building the reactors will lower the cost of the project by about $1 billion.
The rate increase is part of a decade-long series of increases expected annually through 2018.