1. As to the Plaintiff (Counterclaim Defendant)’s KRW 3,832,122,170, and KRW 3,225,959,660, among them, the Defendant (Counterclaim Defendant)’s Counterclaim Defendant’s KRW 3,832,12,170.

1. Basic facts

A. On January 20, 201, the Defendant engaged in the manufacturing of steel tower and steel structure, etc. concluded a contract with the Plaintiff to supply 12 steel towers for the supply of electricity to the Pungnam-gu, Chungcheongnam-gu, Seoul (hereinafter “instant steel tower”). On January 20, 201, the Defendant concluded a contract to supply the steel tower, which was first supplied among the said 12 steel tower, called “Pung 1” and then called “Pung 2 or 12” in the delivery order.

By March 17, 2012, the Defendant supplied the Plaintiff with wind 1 to 12.

b. However, it means the operation of connecting electric wires for the supply of electricity to steel towers for temporary heating at a quarterly point where the electric transmission lines and the new transmission lines are connected.

이 이루어진 때부터 약 열흘 후인 2012. 3. 19. 18:00경 풍세 1호기(총 6단 구조물이다)의 하단으로부터 2단 중간 부분이 가로방향으로 절단되어 넘어지는 사고가 발생하였고(이하 ‘이 사건 사고’라고 한다), 그로 인해 풍세 1호기와 선로로 연결되어 있던 온양-장재 송전선로상의 기설 21호 철탑(이하 ‘이 사건 21호 철탑’이라고 한다)이 장력을 이지기 못하고 철탑 상단 부분부터 좌굴(挫屈)되는 2차 사고가 발생하였다.

C. On June 13, 2012, the Plaintiff: (a) requested a non-destructive test on the steel tower Nos. 2 through 12 to the Korea Mechanical Inspection Station (hereinafter “Korea Mechanical Inspection Station”); (b) conducted a first-wave search test on the steel tower in the presence of the Plaintiff’s employees; and (c) based on the result of the test, determined that there was the following defects (hereinafter “instant defect”) on the steel tower; and (d) notified the Plaintiff of this on June 13, 2012.

1. There is no defect exceeding 3/8 (10m) in the inside of the end-of-life part adjoining to the end-of-life part, but there is a defect that does not comply with the 111 master specifications.