question

coreyzev avatar image
coreyzev asked

Do I need a circuit breaker between SHORE POWER and my MULTIPLUS-ii?

Hi all.

Nearly done my project, but questioning this last bit. I see an EMS often recommended for mobile use in RV parks or Marinas. The one I was looking at is $250, has a 44kA rating, and requires replacement if it encounters a surge.

I thought why do that when I can use a residential breaker, 10ka, that doesn't need replacing?

But also, I see VERY FEW system designs that suggest you need a breaker between shore inlet and your hardware because they expect there to be a functional breaker on the source system.

Thoughts? Why do you think the EMS is 44kA rated? Is 10kA under-valued. Do you need one? did you use one?


Also, how does the multiplus-ii handle low voltage input, eg. 103v instead of 120v?

fusesshorepowerinput current
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2 Answers
chief-queef avatar image
chief-queef answered ·

It depends on your loads and your shore power quality. If you pulling in a lot of current from sketchy shore power the higher the better. However if your not pulling that much and its a good power source I wouldn't be concerned.

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wkirby avatar image
wkirby answered ·

Yes, you should always have a circuit breaker from the shore power. Check your local code or wiring regulations as to whether 10kA is acceptable or there is a requirement for 44kA.
The circuit breaker will be used for protecting your wiring between the shore power and the MultiPlus if a fault does occur. It would be unreasonable to expect third party circuit protection to be adequate for your wiring or for it to be in working order.

The MultiPlus II can accept a Voltage range between 90V and 140V. Voltages within this range will continue to be passed through. AC input will be disconnected and the inverter will start if Voltages outside of these ranges are detected. This Voltage range limits can be adjusted to suit your requirements. Making the range too narrow would cause more frequent disconnects.

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