Fuses or circuit breakers? How do I decide? Which is best for my application? These are questions that power designers and decision makers wrestle with everyday. We looked into this issue, and the results may surprise you!
Fuses and circuit breakers are classified as Overcurrent Protective Devices (OCPDs). Article 240 of the National Electrical Code (NEC) defines them as:
Fuse – An overcurrent protective device with a circuit-opening fusible part that is heated and severed by the passage of overcurrent through it.
Circuit breaker – a device designed to open and close a circuit by non-automatic means and to open the circuit automatically on a predetermined overcurrent without damage to itself when properly applied within its rating.
Fuses and circuit breakers each are available in numerous sizes, ratings, and with a variety of features and characteristics that enable a wide range of solutions/designs.
Here’s the surprise (maybe!). Both circuit breakers and fuses meet the basic NEC requirements for overcurrent protection of electric power distribution systems and equipment, and provide dependable protection in most solutions.
OK, but once again, which is better for a particular application? The answer isn’t simple or easy – several factors are usually taken into account, such as ground fault protection, device interrupting ratings, component protection, selective coordination, and reliability chief among them. There are a number of good resources available from fuse and circuit breaker manufacturers detailing the capabilities and merits of each. Often times it boils down to cost…but the difference there is not always evident. Fuses are generally less expensive, but they are consumables and must be replaced after a fault condition, driving an inventory of spares. Circuit breakers are more costly, but can be re-used through many mechanical or electrical operations. Look for future blog posts detailing the benefits of both fuses and breakers.
So, fuses or circuit breakers? You tell us! Trimm designs and sells a wide portfolio of fuse panels, circuit breaker panels, and panels that can use either interchangeably – or both concurrently!