Can help to buy be used for second home?

No. If you can afford to purchase another home you will have to repay the Help to Buy: Equity Loan.
The property purchased must be your only residence. Help to Buy is not available to assist buy-to-let investors or those who will own any property other than their Help to Buy property after completing their purchase.
You cannot rent out your existing home and buy a second home through Help to Buy.
Applicants who make fraudulent claims for Help to Buy assistance will be liable to criminal prosecution. Fraudulent claims will always require immediate repayment of the equity loan.