FAQ

Frequently asked questions about Emcomps circuit breakers

A circuit breaker transforms a change in an electric current to a mechanical movement that interrupts the circuit. A thermal circuit breaker does this through a bimetal element that heats up and bends. So, heat trips the circuit breaker.

In an hydraulic-magnetic circuit breaker, the current travels through a coil that generates a magnetic field that trips the circuit breaker. Therefore, heat is not a factor in tripping a hydraulic-magnetic circuit breaker. This means that a hydraulic-magnetic circuit breaker is always tripped by rated current, regardless of the ambient temperature. Other benefits include smaller module size and lower critical resistance.

Yes, as the mechanism is temperature-independent, high or low ambient temperature is not a factor. But, for example at 40 degrees below zero the action of the breaker will be somewhat more sluggish and at 85 degrees it will be more rapid. But it will always keep to the stated rated current.

An auxiliary switch generates a signal that indicates whether the circuit breaker is on or off, but cannot distinguish between whether it has been manually switched off or tripped by an electrical fault. An alarm switch generates a signal that indicates whether the circuit breaker was tripped by an electrical fault, but not whether the breaker is off or turned on manually.

The handle of the circuit breaker is able to visually indicate whether it was tripped by an electrical fault. The handle stops in an intermediate position, between on and off.

Yes, many of the circuit breaker families can remotely be switched off by a trip signal. Either a voltage or a current pulse. The latest development for the DD-frame range is also a fully remote operated circuit breaker.

A motorized unit enable the circuit breaker to both switch on and off, as well as re-set after a fault.

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The life of a circuit breaker is determined by a number of factors. For example: how many times it will be tripped on/off, if it is done under load or not and of course whether the breaker is subjected to short-circuit currents. There are also differences between the various product families. The advantage compared to conventional, thermal, circuit breakers is that the mechanism that regulates the trip functionality is hermetically sealed and is not subjected to wear and tear from dust and other airborne particles.

All of Emcomp's MCB families have detailed reliability data that can be provided on request.

Yes, to some extent. The circuit breaker is built to be mounted vertically, but once in place, it can be rotated around its own axis. In other words, it can be vertical, horizontal or turned completely upside down. But if you wish to mount the circuit breaker horizontally, i.e. with the handle pointing upwards (for example standing on a table) or with the handle pointing downwards (for example mounted on the ceiling) its properties will be affected.

A circuit breaker with the handle pointing upwards will trip a moment earlier than specified due to gravity speeding the mechanism up. And vice versa, a circuit breaker with the handle pointing downwards will trip a moment later as gravity acts in opposition to the mechanism. Conversion tables to compensate for this are available.

No, one of the strengths of Emcomp's circuit breakers is that they have a global approval profile. The same component can have UL approval for America, IEC approval for Europe, CCC for China, etc.

Most of our circuit breakers are also approved as disconnecting switches.

Yes, Emcomp's busbar mounted circuit breakers have a special lock that make it possible to lock the handle in the on or off position. Our front-mounted circuit breakers have different handles for managing unintentional tripping. One such example is the ”Flush-Rocker” handle, which is completely flat when the breaker is on in order to minimise the risk of an unintentional trip.

Naturally we have a range of standard phase busbars, both fork-type, mounted below the terminal screw, and pin-type, mounted on the breaker's terminal.

Yes, our application engineers use CAD software to create solutions that match your unique needs.

Yes, one of the advantages of the hydraulic-magnetic principle is that it enables a more precise method for creating different properties. Both fast and slow curves, with pulse tolerances, etc. Emcomp provides a number of standards.

Yes, this is called “trip free operation”.

Even with the handle blocked in ON position, the breaker will trip if an overload occurs.

The basic construction is very similar if not the same, however, there are some differences in the number of turns on the coil for DC, as well as the changes in the tolerances on components to ensure DC performance.