Where to Use TP, TPN and 4P in Distribution panel


For any Distribution board, the protection system (MCB) must be used in the incomer. For a three phase distribution panel either TP or TPN or 4P can be used as the incoming protection.

TP MCB: It is most commonly used type in all ordinary three phase supply.

TPN MCB: It is generally used where there are dual sources of incomer to the panel (utility source and emergency generator source).

4P MCB: It is used where is the possibility of high neutral current (due to unbalance loads and /or 3rd and multiple of 3rd harmonics current etc) and Neutral / Earth Protection is provided on Neutral.