The Power Supply voltage range is +12-19 (+/-10%) VDC (see page 55 of TPS https://www.intel.com/content/dam/support/us/en/documents/mini-pcs/nuc-kits/NUC7i5BN_NUC7i7BN_TechPr...). So, in this case applying 24VDC may damage the NUC Power Supply circuits and therefore void the warranty.
Leon
