We were wondering if it is possible to input the cost of renting of equipment in the FP7?

Costs for renting equipment may be eligible, but are subject to the following:
a) Justification of the necessity of the equipment in the project and why it is more cost effective to rent the equipment than to buy it.
b) Please note that any interest element (e.g. in the case of leasing) is not an eligible cost.
c) Only the portion of the equipment used on the project may be charged. The amount of use (percentage used and time) must be auditable

In FP7 there is no "equipment category". Costs should be reported on the Form C as either Direct Costs or Indirect Costs, depending upon the normal accounting practice for handling this type of cost in your organisation.