My full time job is a maintenance engineer, part time, I'm small domestic electrical work. In the factory where I work contractors are installing new circuits to a sub 3 phase board. Rcd has been installed after the breaker although I know you can buy rcbo's for this board. Nothing wrong here though. My interpretation of the regs is surge protection is required as it's a new circuit in commercial premises. What am I missing as they have done a few new circuits but never fitted surge protection. Also I'm on nights when they have been working so cant ask.The main incomer doesnt have for this subboard doesn't have upfront surge protection.