Ground fault circuit interrupters (GFCI) disconnect a circuit when the current between the neutral conductor and the live conductor becomes unbalanced. These electrical protection devices are also known as residual current devices. Ground fault circuit interrupters (GFCI) are available as both single devices and arrays. In a single device, there is only one GFCI in the package. In an array, there are several GFCIs in a single package. When selecting a GFCI array, the total number of devices in the package is an important parameter to consider.

Ground fault circuit interrupters (GFCI) differ in terms of mounting or packaging style. Choices include surface mount technology (SMT), bolt-on, panel mount, and through-hole technology (THT). GFCIs with axial leads, gull wing leads, J-leads, radial leads, screw terminals, and tab terminals are also available. Some ground fault circuit interrupters (GFCI) have a flip-chip mounting style that does not require the attachment of wires to an integrated circuit (IC) chip. Others use an IC package style such as small outline integrated circuit (SOIC), shrink small outline package (SSOP), SC-70, or SOT23.

Performance specifications for ground fault circuit interrupters (GFCI) include supply voltage, trigger voltage, current surge, response time, and operating temperature. Supply voltage (VS) refers to the source-voltage range. Trigger voltage is the maximum voltage that will trigger the device. Current surge is the rated, maximum value of the peak impulse current that the suppressor can withstand. Response time is the elapsed time between the triggering of the suppressor and the beginning of the response. Junction operating temperature (Tj) is the range of temperatures over which ground fault circuit interrupters (GFCI) operate.

There are several standards and certifications for ground fault circuit interrupters (GFCI). Some products comply with RoHS, WEEE, or ELV directives. Others bear marks from organizations such as Underwriters Laboratories (UL) or the Canadian Standards Association (CSA). Restriction of hazardous substances (RoHS) is a European Union (EU) directive that requires all manufacturers of electronic and electrical equipment sold in Europe to demonstrate that their products contain only minimal levels of specific hazardous substances. Waste electrical and electronics equipment (WEEE) is an EU directive designed to encourage the reuse, recycling and recovery of electrical and electronic equipment such as ground fault circuit interrupters (GFCI).