Why Fuse Used in Both Case of DC Supply

Hi,

With DC protection , you need to look at how your source grounded.

If the source is floating then you need to provide protection against SC across the leads of the load . Also against ground faullt which can occur between any lead and GND. In this case you need to ensure you have protection across both polarities.

If you supply is earthed via (-) terminal then you can get away with one fuse although some still recommend another fuse on (-) . If the supply has a mid pont connection to earth then you need protection on both leads.

It is best that you use CB instead of a fuse since CBs to minimise down time when fuse needs replacment and also provide pilot monitoring.

You may contact you nearest Schneider Electric office for assistance in sizing the DC CB.

cheers

use the link below

http://www.schneider-electric.com.au/sites/australia/en/products-services/electrical-distribution/products-offer/range-presentation.page?c_filepath=/templatedata/Offer_Presentation/3_Range_Datasheet/data/en/local/electrical_distribution/c60h_dc.xml&p_function_id=17&p_family_id=178&p_range_id=2157&f=F13%3AElectrical%20Distribution~!NNM1:Circuit+breakers+%26+Switches~!NNM2:Modular+Circuit+Breaker~!NNM3:C60H-DC