Lighting Circuit Breaker Size

In other words the breaker controlling a circuit should be 125 percent of the continuous load maximum current expected to last for three hours or more and 100 percent of the non continuous load.

Lighting circuit breaker size. Using the specification sticker. Note that not all mcb manufacturers specify these data in the datasheets of their circuit breakers. A 30a circuit breaker can safely carry the exact 30a current but nec suggests 80 as a safe current limit as compared to the rated current. What that means is that your total amperage will equal your watts divided by volts.

The size of a circuit breaker is the maximum current that can pass through the breaker without tripping the circuit and causing a loss of power. Difference between circuit breaker and isolator disconnector circuit breaker size calculation for continuous non contentious load. Sizing the circuit breakers rev 03 1 page sizing the circuit breakers with the fixture s current draw information the installer can calculate and select the right circuit breaker size rating to which they can connect a group of fixtures. The following provides several methods that can be used.

A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit its basic function is to interrupt current flow after a fault is detected. Amps watts volts. I was assuming the op was talking about a standard domestic installation with floods added to the lighting circuit dave. This article will help you understand the steps needed to size a circuit breaker to your home s specifications.

You should ask for the maximum inrush current capability of your circuit breaker of choice. Unlike a fuse which operates once and then must be replaced a circuit breaker can be reset either manually or automatically to resume. Breaker size is dependent on the wire size used for the electrical circuit for example a 15 amp breaker would protect a 14awg circuit and trip when a load of approximately 1800 watts is exceeded. Some electrical codes tell you what the maximum on a lighting breaker size is.

For instance abb s s200 16a type b mcb has a maximum inrush current capability of 672a at 200μs and 533a at 250μs. So check with your regional code. As circuit breakers cbs and overcurrent protection devices ocpd are designed for 100 rated current i e. One of the most often asked questions is how do i size a circuit breaker a commonly misunderstood fact about circuit breakers cbs is related to the percentage of loading permitted by the nec and the cb design and why the two may be different.

There is a calculation that you can do to figure out the proper breaker size. I suppose if it s a dedicated circuit for the floodlights you could use whatever size breaker was necessary for the load and cable size etc. Office lighting typically meets this qualification.