Yes, the J-box must be 30" instead of 24".According to the National Electrical Code (NEC), a pull box must have the following minimum dimensions: For each 90-degree angle of deflection, add 6 inches of straight run for each 10 inches of outlet diameter. For 4-inch conduits, this means that you need 24 inches of straight run for each 90-degree angle of deflection.In your case, you have two 4-inch conduits entering the side of the J-box, and two 4-inch conduits exiting the adjacent side. This means that you have a total of two 90-degree angles of deflection. Therefore, you need a total of 48 inches of straight run.The J-box that you are currently using is only 24 inches long, which is not enough to meet the NEC requirements. Therefore, you need to use a J-box that is at least 30 inches long. Flag for review