Electrical Question

All 4 contacts break at the same time in a 4 pole MCCB. In a TP+N neutral breaks just after the phase contacts.

TPN will mean triple pole with Neutral. TPN will mean a 4Pole device with 4th Pole as Neutral. 4 pole mccb has 4 poles. Basically both look same, except the current carrying capacity of neutral pole is less than the other poles.

Go through the recent threads,you will find the answer.

In TPN (three pole + neutral) breakers, only three phase poles would have the releases (thermal & magnetic) and the fourth neutral pole is only a switch without any releases in it. Whereas in four pole breakers, all the four poles would have releases. But, this is more a feature in MCBs only and NOT in MCCBs. In MCCBs you either have three pole or four pole. TPN MCCBs are unheard of as a product. May be, a three pole MCCB with external isolable neutral is called a TPN MCCB is tender specifications.

The choice of Three Pole MCCB + Isolabe Neutrla over a four Pole MCCB is economical, as the first arrangement is chaeper than the second.

Hope it is clear.