For reference LP1D80008MD, it had a failure after 1 milion operation although it's mechanical durability is 4 million operations .
The mechanical durability of the Contactor indicates the mechanical life of the contactor parts when is is operated at no no load .i.e. only the coil is switched on and off without any connections on the pole. The mechanical durability is 4 million cycles with an operating rate of max. 3600 per hour.
The electrical durability is an imporant parameter as it takes into consideration the ON-Load operation of the contactor.
The provided details do not indicate the utilisation category / load/ temperature conditions and operating rate which also plays important role in the selection of the contactor.
we have enclosed the charactersitics curves for the selection of contactor on AC3 / AC1 utilisation based on the electrical durability and the pages have some clear examples for selection.
For the 4 pole contactor as mentioned, we can assume the application to be an AC1 ( unless specified otherwise).