Most terminal blocks will be certified and/or designed to UL and/or IEC safety standards. Each agency uses a different standard that a terminal block must adhere to, so engineers will often find both ratings on a datasheet with differing values, typically residential wiring codes are less restrictive than commercial or industrial wiring codes. However, it is important for engineers to know their overall system safety requirements and to make sure that the terminal block is rated for the type of wire and current that will be used in the circuit in order to select a terminal block that will be in compliance.
Other design considerations can include color customization of a terminal block’s housing or buttons. This can help to differentiate between various terminal block connections in complex systems, making it easier to diagnose connection points in the field.
