Fuse for 3000 w inverter

[wullie]

Just wondering size fuse to fit at batteries for inverter, 5 batteries 110 amp.

[WotEver]

I would have thought a 400A fuse. Do the inverter instructions not suggest the fuse size?

[Keith M]

As a minimum 300 / 350 amps using either a T class or ANL fuse.

It will partly depend on the peak power

 

 

Keith

Edited February 20, 2017 by Keith M

[ditchcrawler]

How thick are the wires?

[Giant]

The manual for our Victron 3kW unit specifies a 400A fuse.

[system 4-50]

I assume your Victron has a substantial internal fuse like mine, so the fuse you are installing is to protect the wiring between the batteries and the Victron and therefore should be related to the wire size, which is in turn related to the current you expect to take through it. Have I got that right?

I use a lower fuse than the wiring can take to check that I am not taking more than I expect to be ever needed.

[Keith M]

Where did Victron come from

 

There are plenty of other 3000 watt inverters out there

 

 

Keith

[pearley]

I assume your Victron has a substantial internal fuse like mine, so the fuse you are installing is to protect the wiring between the batteries and the Victron and therefore should be related to the wire size, which is in turn related to the current you expect to take through it. Have I got that right?

I use a lower fuse than the wiring can take to check that I am not taking more than I expect to be ever needed.

My 5 year old Victron Combi doesn't have an internal fuse.The one it replaced did.

Edited February 20, 2017 by pearley

[Robbo]

Misread, ignore

Edited February 20, 2017 by Robbo

[b0atman]

Not all inverters have fuses fitted DC or AC my Victron 3000 doesn't.

[WotEver]

Not all inverters have fuses fitted DC or AC my Victron 3000 doesn't.

Are you talking about for inverter protection or cable protection?

 

Not all inverters have user accessible fuses, that's true. However, all inverter DC feeds (and/or charger outputs) should be fused to protect the cable.

[Giant]

Where did Victron come from

 

There are plenty of other 3000 watt inverters out there

 

That came simply from the fact that I quoted the recommendation for our Victron unit.

 

Would you expect the necessary fuse rating to differ that much between inverters of the same rating? They're all going to draw about the same amount of DC current to supply 3kW AC, give or take a few % of efficiency.

[Detling]

The fuse should reflect the cable capacity. If the cable can carry the required nearly 400 amps for full power use including any start surge ( most inverters are capable of 25% overload for a few seconds) then fit a 400A fuse, if using thinner cable, fuse to save the cable but carry spares as someone will probably switch two mains things on at once, thus exceeding the lower rating you have imposed on the inverter, causing the fuse to blow.

[WotEver]

It makes zero sense to wire an inverter with cable that's 'too small'. What happens when someone turns on a kettle while the DVD player and TV is on?

 

70mm² should be fine for a 3kW inverter unless it is a long way from the batteries. A 400A fuse will protect a 70mm² cable just fine.

[ditchcrawler]

We all know that would be zero sense but it happens