A Type B NH MCB Distribution Board, in heavy gauge steel and are rust protected and highly resistant to both weathering and mechanical damage. It is incorporated in the distribution boards are multi-terminal dual earth and neutral bars. This WYLEX PSB miniature circuit breakers is rated at 10kA and are of the fault limiting type. When a short circuit occurs, the current operates a solenoid which trips the mechanism and forces the moving contact away from the fixed contact. The arc generated is forced into an arcing chamber which incorporates splitter plates, to divide and cool it, reducing the total operating time to less than 5ms, This high speed operation substantially reduces the ‘let through’ energy (I2 t) keeping additional damage at the point of the fault to a minimum.