So you've never done it before, and you're going to go ahead without knowing what the risks are, and without any appreciation of the dangers?
Do you have the knowledge required to replace the CU? What's your background, given that you first called it a "mains board"?
Do you have the test equipment needed?
Do you know that replacing a CU is notifiable?
Do you have the knowledge required to replace the CU? What's your background, given that you first called it a "mains board"?
Do you have the test equipment needed?
Do you know that replacing a CU is notifiable?