Victron Lynx PowerIn – Class T Fuse & Battery Switch

In a recently installed solar system I use a Class T fuse between the Trophy battery bank and the inverter. A Class T fuse is a fast-acting, high amp rated capable fuse.

I installed a 300amp fuse based on the anticipated current draw for size inverter that the system has (6kw, 50aAC, 150aDC max). The fuse is placed directly after the Victron PowerIn that is the busbar for 3 x 105ah LifePO4 batteries connected in parallel. The Class T fuse can handle a 20,000aDC inflow without failing. Do not confuse this with the 300a interrupt rating of the fuse. The 20,000aDC inflow rating means that the fuse will maintain its integrity even at 20,000aDC. You can’t get that with a fuse such as an ANL and most DC circuit breakers.

I did not use a ‘lug’ style connection point with the PowerIn because cost was a factor, the Class T fuse holder is a mechanical version…a used one I had access to. Meaning, the insulation stripped cable goes to the fuse holder is placed into a mechanical lug which is tightened down. I did however use a feral to keep the cable end from deforming and losing connection integrity.

But, this installation presented a bit of a problem…an exposed PowerIn connection point with exposed lug. No way you want an exposed high current connection point such as this. Just think about a young child, or yourself, touching the exposed lug and completing a circuit! Or dropping a tool that makes contact with both points. Yuck!

Fortunately there is an easy fix to this situation…wire trays, wire raceways, wire ducts, etc.; they go by a number of different names. But they are simple is concept…plastic constructed boxes to protect wires.

In the picture below I simply cut a very short piece of wire duct to fit between the PowerIn and the Class T fuse holder. With the wire duct cover in place a person, or tool, can’t come into contact with the exposed end of the busbar or the wire lug.

The Class T fuse hold comes with a protective cover preventing contact with the fuse, its connection points, etc.

And, if you looked at the picture close enough…you see an exposed lug going into the battery switch. Once the switch is permanently mounted I will cut another piece of wire duct to cover it as well.

Speaking of the battery switch…why do I have one?

Yes, each battery has a circuit breaker…I know that. And each circuit breaker is designed to cut off the flow of power from the battery…I know that too. But, me personally, I like to be able to completely and assuredly disconnect any power flowing between the inverter and the battery bank. And yes, that battery switch is not only rated for the current that will be flowing…it is ‘marine grade’ which is a full step up from normal and common battery switches.

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