A duplex grounding-type receptacle is usually installed in an accessible location under the sink and does not have to be what type of protection?

A duplex grounding-type receptacle installed in an accessible location under the sink typically does not require Ground Fault Circuit Interrupter (GFCI) protection. This is primarily because GFCI protection is mandated in areas where there is a greater risk of electrical shock due to moisture, such as in bathrooms or outdoor settings. However, the location under the sink may not fall under the same stringent requirements as these higher-risk areas if there is no direct exposure to water.

Moreover, installing a GFCI is a best practice for safety, but the question is about the lack of requirement. Thus, this specific setting may allow for non-GFCI receptacles depending on local code interpretations and specific installation guidelines. The use of GFCI units is more about enhancing safety in potentially hazardous wet environments, and depending on the code in force, the receptacle under the sink may be exempt from this requirement.

In summary, while GFCI protection is generally favored in moist settings, the context of a duplex receptacle under a sink could allow for it to be installed without such protection if deemed appropriate by local regulations.