RCBO's

Residual circuit breaker overload

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Features

Designed for harsh environments, Rowe Hankins offers a range of residual circuit breaker overload products. Also known as RCBOs or RCBO’s, these products are industry proven for both rail and traction systems.

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Benefits

What do RCBO's do?

OVERVIEW OF RCBOs

Rowe Hankins Residual Circuit Breaker Overload products (RCBOs) have two main functions:

  1. Firstly, to help to measure AC residual current;

  2. Second, to trip whenever they detect a fault.

The RCBOs are available in 2 and 4 pole configurations – specifically, the 2 pole series 373, and the 4 pole series 368. Additionally, these 2 and 4 pole versions are available at MCB ratings of up to 50 amps and different residual current trip levels.

DETAILED LOOK AT RCBOs

The circuit uses a current transformer to measure AC current imbalance. The signal is amplified, rectified and then passed to a time delay RCBO circuit. If the signal is present after the delay, then a solid-state switch energises the supply circuit breaker trip coil.

Options for either a fixed time delay or an inverse time delay trip characteristic can be specified. Trip currents can be specified for factory setting at levels between 5 and 300mA (Trips levels up to 2A are possible on a 4 pole series). A unit with a trip level of 5mA is specifically suited for the American market to meet the requirements of the ‘National Electrical Code NFPA 70’.

A wide range of time delay RCBOs can be specified and set during manufacture. The detector circuit power supply is derived from the AC supply. A test signal can be injected through the current transformer from a test button to confirm correct operation.