Bill & Judy Rouse <yahoogroups@...>
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BeBe SM #387 does not have an isolation transformer and does not have a breaker before the breaker on the side of the 220VAC electrical panel. That is a GFC breaker rated at 32 amps.
I am not an electrical engineer, so I test electrical devices by touching them to see how hot are charged they are. This has served me well, but I have lost a few brain cells doing this...maybe I'll buy a Fluke one of these days.
Good luck on your project, and don't use the touch-test to test for a load...that only works for us IEs.
On Wed, Nov 18, 2015 at 3:06 PM, Andrew Lamb andrew.lamb@...
Yes just after I posted my message I looked on some of the US calculators and these as you say seem more conservative. I am not at my boat at the moment but I
will certainly take a look at the Amel drawings the next time I am there.
Canet en Roussillion, France
Thanks Andrew, I checked the European wire manufacturers out there and they all seem to indicate that 4mm2 wire is good for up to 32A single phase, so
I think you are correct on adequacy in design. I think the US NEC is just more conservative, hence my concern.
I will retain my 32A breaker, but I still would like to find out why my Amel factory electrical schematics indicate a 16 amp 230V circuit breaker. It
seems you have a 32A breaker, as do I.
What shore power inlet breaker rating is shown on your Amel drawings?
We have a total run of somewhere between 15-20 meters (internal cabling + shore power cable) of twin and earth 4mm2 cross section double
insulated cable from the shore power to the 32A circuit breaker in the engine room, then onto the 7.5KW rated isolation transformer. All the online and offline calculators/calculations that I have done seem to suggest that this is adequate.
Canet en Roussillion, France
Bill, thanks for the feedback. Trust me, I am not trying to question what Amel did, as I am sure they have been installing safe and effective electrical
systems in their boats. And I also agree that I do not want to "de-Amel" my boat. I like it essentially the way it is.
But I do have some concerns that
my Amel 54 may not be configured as Amel intended, and what I have is definitely not safe. I was hoping to see what others have in their shore power systems to see if I have the right setup. Right now I have a
single 32A/230V Hubbel shore power inlet coupled to a 32A/230V circuit breaker in the lazarette feeding my shore power line to the automatic transfer switch in the engine room. The Amel electrical schematics I have indicate there should be a 16A/230V
breaker for the 50Hz feeder and also a 32A breaker for a 120V/60Hz feeder with a step-up transformer. I do not have the 16A breaker or the transformer. I am concerned about
the possibility that someone may connect my shore power inlet to a 230V or 240V connection (which is what you have to do of course whether in Europe or the US) but then try to run everything in the boat. That would overload my 4mm2 wiring.
I certainly am not immune to making mistakes, but I do think I am looking at this correctly. I
am an electrical engineer, so right or wrong I have based my shore power assessments on US National Electrical Code rules. Your approach to determining wire size based on voltage and voltage drop also can be used, but is only really appropriate for DC wiring
and not higher voltage AC systems (whether they are 120V or 230V), where voltage drop is not a concern in a house or boat. Voltage drop is only important if you are looking
at DC circuits (where we are dealing with 12 or 24 volts).
Respectfully, I must also point out a few issues with your numbers. 4mm2, commonly available in Europe, is a cross-sectional measurement of the wire and
not the diameter or circumference. It is the equivalent of a US Wire Gauge Size 11 per the conversion tables. I can see how you might have equated it to a 6 AWG. Since 11 gauge wire is not commonly available in the US, you would have to use 12 gauge wire to
Current through the wire is the issue and not voltage or frequency. 12 gauge wire (or 4mm2) on any AC circuit (less than 600 volts) is
good for up to a 20A breaker and a maximum of 16 amps of continuous current at either 120V or 230V. If you connect a European 230V (or US 240V) power source to a 32A breaker (as I have), the breaker would allow a huge current (up to about 30 amps before tripping)
to pass through my 4mm2 wire. In order to handle that much current, I would need to replace the wiring with 6mm2 wire (or 10 AWG in the US). i do not want to do that, as I agree with you that Amel clearly planned for 4mm2 wiring on the 230V/50Hz shore power
feeder, and hence the rationale for a 16A circuit breaker. Also I think you are correct that the vast majority of power systems available throughout Europe are indeed 16A rather than 32A.
Those are the reasons why I think the circuit breaker I have is wrong and I should degrade it to 16 amps at 230V. Of course, that would
limit my power capacity, but I think that is what Amel would have installed. What size shore power connector and circuit breaker do you have?
I think that you are incorrect on required wire size. How did you calculate
that it is wrong? Based on: Wire Circular mils =2 x ρ x I x L / (%Allowable Voltage drop of source voltage)
4mm = 6 gauge...and 6 gauge is adequate for 230VAC 50htz for 200+ foot length at 3%Allowable Voltage drop.
Is it possible that you have made a mistake? Or, is it possible that your calculations of wire size are based on 110VAC common to the USA?
Also, I would assume that if Amel installed a 16 amp breaker in the lazarette that they would have used 16 amps for a reason...maybe because the vast majority of the 230VAC 50htz shore power connection in Europe and around the world happen to be 16 amp. There
are some marinas with a 32 amp option, but not many. So, it is highly likely that the 16 amp breaker was intentional. We happen to be plugged into 230VAC 50htz 32 amp shore power now, but in this new marina, the 32 amp plug that we are using is the only one
on our pontoon...30 other boats are plugged into 16 amps.
A word of advice to you. The last person you should doubt in terms of Amel systems design is Amel. And the last thing that you want to do with an Amel
is to Un-Amel your Amel.
Also, I sent you a private message.
That definitely helps. So in your case all shore power feeds through the Mass GI 3.5, presumably protected by a 16A circuit breaker in the lazarette?
Is that the size breaker you have?
I have a 32A breaker in the lazarette, which is too large for the 4mm2 wire Amel installed, and it would not safely protect that size isolation transformer.
I plan to change that to a 16A breaker and use a similarly- sized isolation transformer like yours (I am using the Victron 3.6 unit). I just want to be
sure that the breaker doesn't trip all the time if AC loads exceed the 16 amps permitted.
This is the answer from Mastervolt concerning the Installation of charger/inverter on Amel 54
"The AC is not connected to the DC terminals inside, the DC is floating to the housing.
however, the AC input is not galphanic isolated from the shore, for this you need a isolation transformer, and create your own ships ground in your boat.
the combi Ultra has an option to switch on a ground relay, this means the neutral in AC output will be connected to the ground in inverter mode automatically. in charger mode (this means there is a AC input like a shore connection,
then this relay will be deactivated, because theoretical, the hot and neutral line can be swapped, and you don't want the hot line to be connected to the ground.
our high frequency isolation transformer is 88000355 mass GI 3,5http://www.mastervolt.com/products/mass-gi/mass-gi-35-kva-16a-lightweight/
hope this helps,
Edwin van der Kroon"
Any comment ? Wolfgang Weber SY ELISE Amel 54 # 162