Please see attached PDF of Section 7 of the Acti 9 catalog you will need to look at pages 2 to 13 to determine the part required.

There are various current ratings and coil voltage ratings available and they are tested for two different utilization categories (AC7a and AC7b).
AC7a = Slightly inductive loads in household appliances
AC7b = Motor-loads for household appliances

There are two Load Types Slightly Inductive or Resistive and different current type's to take into account (A.C or D.C) we are predominantly dealing with A.C In this range there are also different types of contacts I.E Normally open or Normally closed and there can also be a different amount's of Normally open or Normally closed contact variations so care should be taken to choose the correct contractor for the intended application.

Example:
We require a 2 pole 16A 230V Contactor with 1 Normally open contact (N/O) and one Normally Closed Contact (N/C) For a Slightly inductive load (AC7a) If we look at the table on page 4 of section 7

1) First column Amount of poles required 1-4
2) Second column is the load type resistive (AC7a) 16A or if Inductive (AC7b) the current is derated to 6A.
3) Third column is the voltage range from 12V to 240V.
4) Fourth column is the contact configuration I.E N/O or N/C or a combination of the two.
5) Fifth column is the Part Number of the contractor required. (A9C22715) In this case.
6) Sixth column this is the number of ways in the enclosure that the contractor will use. (NOTE: This is in 9mm modules so for 18mm modules, you must half the number in this column)

Released for: Schneider Electric UK