In the given case, RCM will be applicable on all intra-state supplies as the unregistered delaer cannot make inter-state supply.
Sec. 9(4) of the CGST Act, 2017, “The central tax in respect of the supply of taxable goods or services or both by a supplier, who is not registered, to a registered person shall be paid by such person on reverse charge basis as the recipient and all the provisions of this Act shall apply to such recipient as if he is the person liable for paying the tax in relation to the supply of such goods or services or both.”
Exemption available: The aggregate value of supplies of goods or services or both received by a registered person from any or all the unregistered suppliers is less than Rs. 5,000/- in a day is exempted from GST on reverse charge basis [N.N. 8/2017-Central Tax (Rate), dt. 28.06.2017].