UL Certification required for low power electronic device

We are designing a wall mounted electronic data collection device (simple LCD display and keypad) with an external power supply. I would consider the entire device a low voltage device. I understand in some other countries outside of the US, an electrical safety rating may be required. We are moving forward with FCC certification and we are considering a UL certification. Initially, I thought from a liability standpoint that we would need to UL certification, but I haven’t seen many other low voltage products, other than external power supplies with a UL certification. Is this a common requirement for electronic devices or this a customer based requirement? For example, is there a vertical that specifically requires a UL certification in addition to the FCC? If you know of a previous thread here in the forums describing this, please let me know….thanks..