Consumer Units and Accessories
Welcome to the Consumer Units technical section. Currently we have information regarding the MCBs & RCDs used in consumer units.
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Minature Circuit Breakers (MCBs)
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Miniture Circuit Breakers (MCBs) are current limiting Thermal / magnetic type with each part performing a different function: A) Small Overload Conditions B) High Overload Conditions C) Short Circuit Conditions |
B, C & D Curves for MCBs
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ALL MCBs are now rated at 10kA Short Circuit Capacity with Positive Contact Indication. ‘B’ Curve to BSEN 60898 (Magnetic Trip 3 to 5 Times In) ‘C’ Curve to BSEN 60898 (Magnetic Trip 5 to 10 Times In) |
Residual Current Devices (RCDs)
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An RCD is the term that describes a device that opens the protected circuit when the detected residual current exceeds that of the preset value of the RCD. Under normal ‘healthy’ circuit conditions with all conductors passing through the current Three types of RCD are produced. Each with a specific use: Type A - Tripping is ensured for residual sinusodial alternating currents and residual pulsating direct currents whether the fault is suddenly applied or is a slowly rising fault. Type S - Tripping Devices with built in ‘Time Delay’ for selectivity within circuits having more than one RCD in line. |
Uses of RCDs
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RCDs offer very good protection against Earth Fault Currents, the main areas of application are as follows: Protection against Direct Contact. Protection for portable equipment. |