28/12/2021
Engineering Corner:
What are SP, SPN, DP, TP, TPN, TP+N & 4P Circuit Breakers?
SP CB stands for Single Pole Circuit Breaker. Its switching & protection is affected in only one phase. Therefore, it is applicable for Single Phase Supply to break the Phase only.
SPN CB stands for Single Pole and Neutral Circuit Breaker. Its switching both phase & neutral poles, but protection is affected in only one pole. Therefore, it is applicable for Single Phase Supply to break the Phase and Neutral.
DP CB stands for Double Pole Circuit Breaker. Its switching & protection is affected in both poles. It means neutral pole being protected as well as phase pole. Therefore, it is applicable for Single Phase Supply to break the Phase and Neutral.
TP CB stands for Triple Pole Circuit Breaker. Its switching & protection is affected in only three poles and the neutral pole is not part of the Circuit Breaker. Therefore, it is applicable for Three Phase Supply only (Without Neutral)
TPN CB stands for Triple Pole & Neutral Circuit Breaker. Neutral pole is part of the CB as a separate pole, but without any protective given in the neutral pole (i.e.) neutral is only switched but has no protective element incorporated. It is similarly explained as above SPN CB. Therefore, it is applicable for Three Phase Supply with Neutral.
If the CB it is denoted as TP+N which will mean a three poles Circuit Breaker with external neutral link which can be isolated if required. It is applicable for Three Phase Supply with Neutral.
4P CB stands for four poles Circuit Breaker. Neutral pole is part of the CB, but with a protective element incorporated as other three poles. Therefore, it is applicable for Three Phase Supply with Neutral.
