When do we take the investment available of sales companies as a associate company of calculation in year end?

IAS 28 states that if an investor holds twenty percent more of the voting power of the invested. ie there is significant influence. The significant influence is evidenced in one of the following.

1. Representation on the board of directors 

2 participation in the policy making process etc

The standard requires the use of the equity method  of accounting for investment in associated.

when we have voting power more than% of board of directors 

and after that we can use the equity method in year end