How to calculate an MCB size

[davidmi]

I am doing a campervan conversion and have a 16A/250V shore power connection coming into a consumer unit which has two breakers - one for the AC input into a Victron Multiplus inverter and the other to go to a plug socket for non inverter loads. I would like to know how to size the MCB for the AC input into the inverter - how the calculation is done. So 16amp coming in. The inverter is a 12v/500/20 Multiplus so continuous output power at 25C is 430W and peak power is 900W.

 

[telectrix]

surely the inverter input is 12V D.C. !!

 

[Marvo]

The MCB is there to protect the cabling and circuit connected to it, not the appliance (inverter) on the other end. I would suggest a 10A circuit on a 1.5mm cable from the CU would be more than sufficient.

 

[davidmi]

One feed in from the 12V leisure battery and one feed in from shore power at 240V. It is the consumer box between the shore power connection and the inverter (the AC input) that I am talking about.

 

[davidmi]

The MCB is there to protect the cabling and circuit connected to it, not the appliance (inverter) on the other end. I would suggest a 10A circuit on a 1.5mm cable from the CU would be more than sufficient.

Thanks Marvo!!

 

[MDJ]

surely the inverter input is 12V D.C. !!

Glad your still with us Tel

 

[Lucien Nunes]

The Multiplus is a combined inverter / charger including a transfer switch that I believe can handle 16A regardless of the rating of the inverter itself. The input current will be the total socket load (less whatever is plugged into the raw mains direct socket) plus the charger load of an amp or two. Therefore the input cabling and the MCB protecting it should be rated for the full 16A, to avoid unnecessarily limiting what is available from the sockets.

 

[telectrix]

Glad your still with us Tel

had a few health issues ( water retention was one. boke femur another. where the break was, not repairable as in fix break; needed artty ball joint. now worth a bit in scrap value). spent 2 sessions in horsepital, both issues fixed up to a point. you maybe pleased to know that I'm still using the 1553 wot I bort offa you 10 years ago.

 

[MDJ]

I am really pleased your okay Buddy, glad your still using the 1553, I have forgotten how to use one these days hehe, your a good man Tel, chuffed your health is improving

had a few health issues ( water retention was one. boke femur another. where the break was, not repairable as in fix break; needed artty ball joint. now worth a bit in scrap value). spent 2 sessions in horsepital, both issues fixed up to a point. you maybe pleased to know that I'm still using the 1553 wot I bort offa you 10 years ago.