When a customer's 5KVA MP-II system runs under full load for prolonged periods (read heating hot tub etc.), the terminals on the holder get 60 degrees C although the 70mm2 cables are just warm. Connected and tightened as per the instructions. The terminals on the MP-II also seem a touch hot but I don't actually have a reference as to what is reasonable? Any field experience input appreciated.
Does the fuse holder have adequate cooling? If it is in a small enclosure without air circulation it could over heat.
Cold resistance is about 0.26mΩ, which will increase with temperature rise.
Assuming it is a 48V MultiPlus at full load, that would be 2.6W of heat being dissipated by the fuse when cold (room temperature I presume). As the fuse gets warmer it will dissipate more heat and so increases exponentially.
Check your terminal torque.
Make sure the lug is the right size. Reduced contact area makes heat.
Hottest I have had with ambient at 25 deg C is 40. But it was terminal torque.
Edit:and arrangementnof lugs and fuse...?
