Ground Fault Circuit Interrupter Manufacturers

CERTIFICATION

STANDARD	APPROVAL	MARK	COUNTRY	STANDARD	APPROVAL	MARK	COUNTRY
VDE	Verband Deutscher Elektrotechnikere V.Prufstelle		Germany	S-GS	Intertek Testing Services ETL SEMKO		Europe
NF	Normes Francaises		France	CEE	Internationnal Commission on Rules for the Approval of Electrical Equipment		Europe
SEMKO	Svenska Elektriska Materiel kontrollantalten		Sweden	SEV	Schweizerischen Elektrotechnischen Vercins		Switzerland
DEMKO	Danmarks Elektriske Materielkontrol		Danmark	IRAM	Instituto Argentiono De Normalizacion		Argentina
FI	Suomen Standardisoimislutto		Finland	UC	Inmerto Product Certification		Brazil
NEMKO	Norges Elektriske Materiellkontroll		Norway	GOST-R	Russia Product Certification		Russia
IMQ	Istituto Italano del Marchio di Qualita		Italy	PSB	Singapore Product Certification		Singapore
KEMA	Naamloze Vennootschap tot Keuring Van Elekrtotechnishe Materialen		Holand	ASTA	ASTA Product Certification		U.K
OVE	Osterreichischer Verband fur Elektrotechnik		Austria	BSI	BSI Product Certification		U.K
CEBEC	Norme Belge		Belgium	KETI	Certificate of Compliance		Korea

How does Ground Fault Circuit Interrupter work?

The Ground Fault Circuit Interrupter (GFCI) works based on detecting the difference in current as it enters and leaves the circuit. Before understanding how it works, let's take a look at common circuit structures.

A typical circuit consists of a power source, a load (such as a light bulb or appliance), and the wires that connect them. Under normal circumstances, current should flow continuously from the power supply to the load, and then return to the power supply to form a closed loop. However, a ground fault occurs when the current travels through an unintended path, such as the human body or a conductive body such as water. In this case, the current bypasses the normal circuit between the load and the power supply, creating a dangerous current path that may result in electrical shock.

GFCIs work by constantly monitoring the flow of electricity to and from a circuit. Its core principle is to compare the difference between the part of the current entering the circuit and the part leaving the circuit. Under normal circumstances, these two should be equal because the current in the circuit should be closed. However, if there is a ground fault, some of the current may take an abnormal path, causing the current to be unequal between entering and leaving the circuit.

Specifically, a device called a differential transformer is included in the GFCI, which helps detect differences in electrical current. The transformer does this by producing equal but opposite currents between entering and leaving the circuit. If the magnitude and direction of the currents are the same, the current in the transformer is zero and the circuit remains balanced. However, if there is a ground fault, some of the current will bypass the normal return path and enter the circuit without returning, causing the currents in the transformer to no longer be balanced.

The GFCI periodically detects this current imbalance. Once detected, it will immediately cut off the circuit and interrupt the power supply. This fast response time is critical to protecting people from electrical shock. Typically, GFCIs can respond within milliseconds to quickly cut off the current and reduce the risk of electric shock.

The working principle of the Ground Fault Circuit Interrupter (GFCI) can be simply summarized as follows: by monitoring the difference between the current entering and leaving the circuit, it detects and interrupts the ground fault current in time, thereby preventing the occurrence of electric shock injuries. This intelligent electrical safety device plays an important role in the home, commercial and industrial fields, protecting people's lives and property.