KIAN KUMAR said:
how to work the MCB ? & wha is the principal of the MCB?
how to work the RCCB ? &what is the principal of the RCCB?
Dear Kian ;
the MCB's are Circuit Breakers that are reposnibles to protect any elctric circuit against ” Oveload & Short Circuit ” problems, where are composed of : External body, External connctions, External Handle, Thermal protection, Magnetic protection, Moving & Fixed contacts, Mechansim, Arc shut chamber, and the intsrnal connections.
– The Thermal Protection si reponsible to protect against ” Overload “, where the standard values ” In ” are ” 0.5, 1, 2, 3, 4, 6, 8, 10, 13, 16, 20, 25, 32, 40, 50, 63, 80, 100, & 125A, noting the 8A & 13A aren't used now.
– The Magnetic Protection is reponsible to protect against ” Short Circuit “, where the standard values are : B, C, D, K, Z, noting taht :
– The most using values are : B, C, & D
– B : 3-5 In
– C : 5-10 In
– D : 10-20 In
– By the external Handle and the Mechanism we can close & open the contacts, that means close & open the electric circuit.
– The MCB's can withstand a high values of short circuit currents accordignly the their ” Icu ” values, where the standard of these values are : 1500, 3000, 4500, 6000, 10000, 15000, 20000, & 25000A.
– The relative standard of the MCB's is ” IEC 60898 ” that defines all specifications, Conditions, & the sequences of testing.
the ” RCCB ” is ” Residual Current Circuit Breaker ” that are composed of : External body, External connctions, External Handle, Differencial protection, Moving & Fixed contacts, Mechansim, and the intsrnal connections. These RCCB's are sreponsibles to detect any small difference between Phase & Neutral currents in 2 poles RCCB or between the Phases & Neutral currents in 4 poles RCCB, we call this small current an ” Earth Lekage Current “. Noting that there's no any other protection in the RCCB that means there's no thermal & magnetic protections inside.
– The standard values of the differencial protection : 6, 12, 30, 100, 300, 500 mA, noting that to protect the pepoles we use ” 30mA “, to protecto against fire we use ” 300 or 500mA “, the using of ” 6 & 12mA ” is for a very special applications.
– The standard nominal current are : 25, 40, 63, 80, 100, 125A
– The relative international standard is ” IEC 61008 ” that defines all specifications, Conditions, & the sequences of testing.