A. From March 10, 2014, the Defendant was awarded a subcontract for general electrical construction (hereinafter “instant electrical construction”) at the New Year’s department store 2,488,00,000 won (excluding value-added tax) and the construction period from March 21, 2014 to July 31, 2014.

B. On March 2014, the Plaintiff re-subcontracted the instant construction project with the Defendant during the period from March 10, 2014 to July 31, 2014 by setting the contract amount of KRW 185,00,000 (excluding value-added tax) and the construction period from March 10, 2014 to July 31, 2014.

C. On August 7, 2014, the Plaintiff was re-subcontracted by the Defendant for the inspection and repair of the fire-fighting lines (excluding value-added tax) during the instant electrical construction (hereinafter “instant additional construction”) by setting the contract amount of KRW 44,160,00 (excluding value-added tax) and the construction period from August 8, 2014 to September 5, 2014.

The instant construction project was originally decided to be supplied with materials from the Defendant. However, the Plaintiff submitted a written estimate at the Defendant’s request that the amount be KRW 32,530,00 (excluding value-added tax) to the Defendant, and purchased the machine board from the mentmen Co., Ltd. to KRW 25,146,00 (including value-added tax) and used it as materials for the instant construction project. On June 30, 2014, the Defendant submitted a written estimate at the New World Construction (State) for the payment of the fire reception team value of KRW 32,530,00 (value-added tax separate) and agreed to include the said amount in the construction cost of the instant construction project thereafter.

E. On September 2014, the Plaintiff completed the instant construction and additional construction and completed the trial operation and transfer system to the Defendant, and the Defendant thereafter completed the instant electrical construction and completed the period from September 26, 2014 to September 30, 2016, the guarantee amount of KRW 58,443,00, and the guarantee period from the Electric Construction Mutual Aid Association on September 26, 2014.