Difference between DIN and NEMA circuit breakers

Circuit breakers are widely used in electrical components. Circuit breakers are known as “switches” to turn the power pattern on and off. In fact, the circuit breaker switches electrical circuits on and off, but their main function is related to the safety of the circuits and the electrical installation. The circuit breaker is a safety systems inside the electrical circuit, against overloads and short circuits. In these cases, the circuit breaker has the function of interrupting the current flow in the circuit, since the level of electrical current is higher than that specified in the circuit breaker. In addition to providing safety, the circuit breaker functions as a switching device. In homes, circuit breakers are used to protect electrical and electronic devices. Knowing the importance of circuit breakers in electrical installations, it is important to know the types of circuit breakers most used and which fits the need for your electrical installation.

DIN and NEMA circuit breaker

These two types are better known and more used in low voltage. However, they have a difference between them.

NEMA and DIN type circuit breakers.

NEMA circuit breakers:

The North American NEMAs, or black, are manufactured according to the RTQ standard contained in the INMETRO 243 ordinance. Some information about NEMA circuit breakers:

  • Box manufacturing material:

Heat resistant and chemically stable synthetic resin, Bakelite.

  • Short circuit breaking capacity:

Lower capacity, for example, a common circuit breaker of 25 A type NEMA has an interrupting capacity of approximately 3kA, 66% of the capacity of a DIN type circuit breaker.

  • Constructive characteristic of magnetic firing:

The magnetic trigger and the actuation threshold are not very sensitive. The unlocking of the mechanism depends on the magnitude of the short-circuit current and the protection is by only one bimetal element and its trigger is not wound.

  • Fastening element:

It has terminals with eye bolts and this can cause the cable to loosen over time.

  • Extinguishing element:

The NEMA type models have only one folded plate.

  • Contacts characteristics:

It has only synthesized material.

DIN circuit breakers:

  • Box manufacturing material:

Polyester or urea-formaldehyde.

  • Short circuit breaking capacity:

Considering a 25 A circuit breaker, this model has an interruption capacity in the order of 4.5 KVA.

  • Constructive characteristic of the magnetic trigger:

It has independent firing. Its threshold occurs with a multiple of nominal current, so, regardless of the current value, it will always have two types of actuation, one against short circuit (coil) and the other against overload (Bimetal), acting independently of each other.

  • Fastening element:

This model of circuit breaker prevents the disconnection of the cable through the clamp type terminal with slots.

  • Extinguishing element:

This model has an extinction camera equipped with multiple alerts.

  • Contact features:

Contacts coated with silver, having greater thermal and electrical resistance.

We can conclude that DIN circuit breakers (IEC) have a faster and more efficient response in comparison to North American standard NEMA type circuit breakers.