Ground wiring for one power outlet (Jordledning for ett strømuttak)

I recently installed a Varmepump in my house, and the technician told me we need to prepare ground wiring for the power outlet he plugged into the Varmepump. So, i want to have the ground wiring for that power outlet to be set by someone who can Godkjent. The house is an end Rekkehus on two floors, but the power outlet and the electric meter box are on the same floor.