This spreadsheet intend to calculate of needed Selection of Main & Branch Circuit Breaker for Distribution Box according to the following input parameters.
This spreadsheet provides information for selecting the appropriate main and branch circuit breakers for a distribution box based on the electrical load details. It specifies a continuous load of 98 amps requiring a minimum main circuit breaker size of 200 amps as per NEC standards. It also includes specifications for a 100 amp branch circuit breaker to feed a load of 78.4 amps from Feeder 1. Cable selection details are provided based on load current and maximum cable length.
Selection of Main & Branch Circuit Breaker for Distribution Box
- Calculate Size and Type of Main MCCB/RCCB/ELCB for Continuous Load
- Calculate Size and Type of Main MCCB/RCCB/ELCB for Non Continuous Load
- Calculate Sensitivity of MCCB/RCCB/ELCB.
- Calculate Size and Type of Sub Circuit MCCB/MCB for Continuous and Non Continuous Load
- Calculate Total Load .
- Calculate Max.Length of Cable.
- Calculate Main and Branch Circuit Current
Title : Selection of Main & Branch Circuit Breaker for Distribution Box – As per NEC
Type : Microsoft Excel Spreadsheet (xlsx)
Size : 117.5 KB
FAQ:
What are the NEC rules for circuit breakers?
Step 1 – Size the overcurrent device in accordance with 210.20(A) and 215.3. These two NEC rules require the overcurrent device (breaker or fuse) be sized no less than 100% of the noncontiguous load, plus 125% of the continuous load. Step 2 – Select the conductor to comply with 210.19(A), 215.2, and 230.42(A).
How to choose A main circuit breaker?
- Factors to Consider When Choosing a Circuit Breaker
- Electrical Load. Determine the total electrical load of the circuit. …
- Voltage Rating. Ensure that the voltage rating of the circuit breaker matches the voltage of the electrical system. …
- Current Rating (Amperage) …
- Trip Curve. …
- Compatibility with Panel. …
- Safety Certifications.
Which circuit breaker is used at distribution level?
Since there are lot of voltage levels in a Distribution station, based on the voltage level and the fault level, specific breakers will be used. Air Circuit breakers (and also Air Blast circuit breakers which are very old) are generally used for the LV range.
How do you size a NEC main breaker?
the nec says we should size the circuit breaker at 100% of the non-continuous loads and 125% of the continuous loads, so we have the equation; (100% * 150) + (125% * 600) = 900a. this means we would use a 1000 amp frame circuit breaker set at 900 amps.
