The current limitation benefits all downstream circuits that are controlled by the current-limiting CB concerned.
The principle is not restrictive, i.e. current-limiting CBs can be installed at any point in an installation where the downstream circuits would otherwise be inadequately rated.
The result is:
• Simplified short-circuit current calculations
• Simplification, i.e. a wider choice of downstream switchgear and appliances
• The use of lighter-duty switchgear and appliances, with consequently lower cost
• Economy of space requirements, since light-duty equipment have generally a smaller volume