ELCI breaker before or after inverter?

[aybabtme]

Hi folks,

I'm adding a Victron MultiPlus inverter between shore power and the main breaker of my 120VAC panel. My current AC panel has a single throw main breaker, and there's no ELCI on the boat.

I want to add an ELCI with double pole breaker in the circuit, and I'd want it to be effective when the boat is powered with the inverter only. Basically, I consider the inverter as the main AC source. Which makes me think that I should put the ELCI after the inverter, replacing the main panel's AC single pole breaker. Then I'd add a regular double pole breaker to the shore -> inverter cabling.

Is this okay? Or must I put the ELCI breaker on the shore input line, before the inverter?

[tkeithlu]

How much unfused AC cable are you comfortable having in your boat? General rule is put the breaker as soon as possible, because any unfused (or unknown unfused somewhere at the marina) wire can give you a nasty and dangerous AC fire. As in, run like hell.

[aybabtme]

There's going to be a breaker before and after the inverter, so nothing unfused, but I'd like to buy only 1 ELCI one if possible. I feel that putting it after the inverter will actually provide more effective protection given that the inverter is the primary source of AC.

[Dsanduril]

An ELCI on the output of the inverter will protect in both invert and shore modes, so provides the most protection for the money. However, it will do nothing to protect for faults in the wiring between the shore power inlet and the inverter or inside the inverter itself. Whether to put a second ELCI on the shore side is a risk tolerance question. Personally, we have a similar setup and have a second ELCI mounted on the back side of the shore power connector on the boat. There’s about 150mm of unprotected wire between the shore power terminals and the shore side ELCI. That was our decision, YMMV.

[tkeithlu]

Hmmm. GFCIs are cheap to install in every outlet, saving your going back to the panel, and supplying better protection because they respond to a smaller imbalance in current than do ELCIs. You have some reason to prefer ELCIs, so at their cost you probably want a central unit at the panel. I went with GFCis, and my only complaint is very occasionally needing to reset one of the on-deck outlets before I use it. They are in gasketed boxes, so it doesn't happen often. I've never felt a shock from a GFCI circuit.

[evm1024]

I use an ELCI before my victron inverter/charger and also GFCI on individual AC circuits in the boat.

It should be noted that the ELCI has a 30 mA leakage current trip and the GFCI have 5 mA trips.

Thus the ELCI is there primarily to protect people in the water near your boat should there be a fault in your boats wiring causing leakage current intot he water. (30 mA)

And GFCI are there to protect the people in your boat in the event they coming in contact with a hot conductor. (5 mA)

You need both.

[CharlieJ]

@evm1024 post#6: +1

[CarinaPDX]

FWIW as of 2010 the ABYC standards require an ELCI on the power inlet, with the over-current protection on both conductors (which is usually integral with the ELCI). This protects against any problems with the wiring to the inverter/charger, as well as the inverter/charger itself, and all downstream AC devices when on shore power. Just do it that way. It is the right thing to do.

The AC output of the invert/charger will also need a 2-pole circuit breaker for disconnect/overcurrent protection. Considering that you will have installed weather-resistant GFCI outlets, a second ELCI at the inverter output will only add leakage protection for the downstream AC devices that are hard-wired and for inverter output only - a much smaller set of potential problems. If you currently have a 2-pole breaker then it may not be worth buying a second ELCI; if you need to buy a new 2-pole breaker then it might be worth paying for the second ELCI instead.

Greg

[ramblinrod]

Ideally, you will have a shore power inlet, and within 10ft an AC source panel equipped with ELCI main breaker, source control switch if you have a generator, shore power only load breakers , such as water heater, A/C, and any chargers (including one for the multiplus) etc.

From the multiplus AC out, you connect your load panel, equipped with a main breaker, and all “inverter load” branch circuit breakers. From these any receptacle in a head, galley, machinery space (no gasoline engine compartment or battery compartment) and space possibly exposed to weather, needs to be GFCI protected.

(ABYC Electrical and Marine Systems certified technician).

Make sure the water heater is protected by the ELCI.

[ttex]

Have had to put an ELCI in swimming pool equipment breaker boxes for a while now as well.

People keep thinking im making stuff up when I say the replacement breaker is 100 dollars.

[OS2Dude]

In researching my issue with my marine air and an ELCI, I read that inverters and ELCI breakers do NOT play well together. The AYBC rules require the neutral and safety ground to be bonded when the inverter is the power source, but not when the shore power is the source. The switch over takes enough time that the ELCI will see the current 'leak' to the safety ground and trip. You will need to research how to deal with this issue.

[mroc]

Hi All,
I am just about to install ELCI and the agony where to put it drags on.

I have a simple 120V 30A shore power with a galvanic isolator already installed. I also have a Victron 2000W inverter/charger with a 120V input that is not hard wired. I connect it manually via an extension cord when I want a quick charge on anchor from my generator or shore power. When on shore power, I use only Xyntrex 40A charger. I want people to swim safely around my boat when on shore power, generator, or on anchor making morning esspresso (inverter ON with no external 120V source).

My plan was to place the ELCI upstream to my main (and only) 120V panel, downstream my shore/inverter transfer switch and this approach was initially blessed by my friendly electrical guru.
But I read numerous warnings NOT to place ELCI downstream the inverter as the inverter has apparently a nasty habit to connect grounding and neutral for a short period after being turned on. This brief interconnection is apparently enough to trip the ELCI and render the inverter useless. I guess, I could test this approach, but it is a lot of work, so I rather get someone advise.

Upon carefull consideration I am now planning to install ELCI right at the inlet of shore power as per ABYC guidelines and live with the risk of no ELCI protection of inverter's 120V. This risk is, to my understanding, neglibeable as the main source of current leakeage (electrical water heater) will be switched off when inverter is on. My inverter runs the entire 120V panel and I have to manually switch off the water heater and battery charger before running inverter. When I forget (and yes, I do occassionally and will install some automation here soon), the inverter shuts off on overload or reverse polarity, so I assume my crew will be safe swimming when I am making esspresso on anchor. As another precaution I was advised to connect the inverter casing ground with the boat grounding bus. I do not understand the logic behind it and if it is OK with the inverter wellbeing, but I will try and see.
All outlets are protected by GFPI so I cannot think of any swimmers safety issues.

Anyone went through this exercise?
Any comments?

Best regards

[smac999]

under ABYC you need a main elci before anything. within 10' of the shore inlet.

if you wanted one after the inverter you'd need 2. you can't have stray current leaving the boat from an inverter. so it's less usefull there.


the battery charger and hot water heater should be run from ac2 output of the multiplus. this will save you from having to switch all the time.

[mroc]

Thanks smac999. Sounds like a decisive and competent suggestion. As I mentioned, I am planning to do just as you suggested. I would appreciate a bit of explanation why I can’t have strait current leaving the boat from the inverter.
Big thanks

[s/v Jedi]

Originally Posted by mroc

Thanks smac999. Sounds like a decisive and competent suggestion. As I mentioned, I am planning to do just as you suggested. I would appreciate a bit of explanation why I can’t have strait current leaving the boat from the inverter.
Big thanks

The inverter output is galvanically isolated from shore power so the only return path for a circuit is back to the inverter. It is a new AC power source.

You can get the same safety from shore power by using an isolation transformer.