Sorting through AC electrical system.

[PierreR]

I gained a lot of information from this thread. Enough to maybe talk some sense.
https://www.trawlerforum.com/forums/s4/isolation-transformer-neutral-ground-connections-70843.html

I bought my boat 15 months ago in Madisonville LA and needed to get the boat back to Sandusky Ohio. This boat had no inverter and I was faced with running the generator the whole time I was enroute or installing an invertor. The generator at the time was new and was not wired in. Original internal electric controls for the generator did not exist. I had to figure that out.

I wired in the invertor (Victron MultiPlus 2KVA 120V) as per instructions. The invertor switches fine from shore power to invertor but not the other way around. With everything off that draws power, I can switch on shore power. When I do, I get a temp overload that switches to charger mode in a minute or so and then I can turn things back on. If I have much of anything drawing power I need to turn everything off and reset the invertor.
Should be easy enough to fix except that I have zero wiring diagrams for this boat. No circuits what so ever.
there are at least two isolation transformers and I suspect there is a third hidden out of sight that controls two of the three air conditioning units.

The boat owners manual said the boat came with two 30amp shore power circuits two two transformers. One hidden out of sight and one the lazarette. Current shore power is one 50amp 240v to a 15KVA 120/240 transformer and one 30 amp 120 v. to a 5KVA 120/240v transformer. I suspect the third is 5KVA 120/240 as well. There is a switch with 120V-off-240V and a manual Generator transfer switch.
When on 50amp shore power and the switch in 240 volts, I can measure 240 volts between the two halves of the AC panel and I have all AC units operable. When I am on 30 amp 120v with the switch in 120v I measure 120 volts between the two halves. Everything will work but I only have 30 amps to work with. I also have a 50 amp 120v cord that gives me 50 amps everywhere when switch is in 120v. I determined the original generator was hooked up 120v so I did the same with the new generator. I have nothing on the boat that uses 240 volts

I have every reason to believe the AC shore power system was hooked up by a professional as neither of the two previous owners were electrical savvy. After reading the referenced thread above the problem might be as simple as me not understanding these transformer grounds can be wired two ways and I picked the wrong one in hooking up the invertor.

I will be going to the boat tomorrow and attempting to figure out how things are wired from shore power and make a diagram so we can talk some sense. When I say attempting that does not me I question my capability of understanding. It means my body may not cooperate in the spaces allowed. 15 weeks out of rotator cuff surgery. There are places in this boat that I have not actually seen yet. I had a 19 year old on board for the trip that could get into those spaces and describe for me what was there.

Time for some detective work. Could I hire this work to be done? Yes but there is still no wiring diagram and I would still not understand what I have. Time to get one of those meters that is wireless for continuity.

 

[Bmarler]

I gained a lot of information from this thread. Enough to maybe talk some sense.
https://www.trawlerforum.com/forums/s4/isolation-transformer-neutral-ground-connections-70843.html

I bought my boat 15 months ago in Madisonville LA and needed to get the boat back to Sandusky Ohio. This boat had no inverter and I was faced with running the generator the whole time I was enroute or installing an invertor. The generator at the time was new and was not wired in. Original internal electric controls for the generator did not exist. I had to figure that out.

I wired in the invertor (Victron MultiPlus 2KVA 120V) as per instructions. The invertor switches fine from shore power to invertor but not the other way around. With everything off that draws power, I can switch on shore power. When I do, I get a temp overload that switches to charger mode in a minute or so and then I can turn things back on. If I have much of anything drawing power I need to turn everything off and reset the invertor.
Should be easy enough to fix except that I have zero wiring diagrams for this boat. No circuits what so ever.
there are at least two isolation transformers and I suspect there is a third hidden out of sight that controls two of the three air conditioning units.

The boat owners manual said the boat came with two 30amp shore power circuits two two transformers. One hidden out of sight and one the lazarette. Current shore power is one 50amp 240v to a 15KVA 120/240 transformer and one 30 amp 120 v. to a 5KVA 120/240v transformer. I suspect the third is 5KVA 120/240 as well. There is a switch with 120V-off-240V and a manual Generator transfer switch.
When on 50amp shore power and the switch in 240 volts, I can measure 240 volts between the two halves of the AC panel and I have all AC units operable. When I am on 30 amp 120v with the switch in 120v I measure 120 volts between the two halves. Everything will work but I only have 30 amps to work with. I also have a 50 amp 120v cord that gives me 50 amps everywhere when switch is in 120v. I determined the original generator was hooked up 120v so I did the same with the new generator. I have nothing on the boat that uses 240 volts

I have every reason to believe the AC shore power system was hooked up by a professional as neither of the two previous owners were electrical savvy. After reading the referenced thread above the problem might be as simple as me not understanding these transformer grounds can be wired two ways and I picked the wrong one in hooking up the invertor.

I will be going to the boat tomorrow and attempting to figure out how things are wired from shore power and make a diagram so we can talk some sense. When I say attempting that does not me I question my capability of understanding. It means my body may not cooperate in the spaces allowed. 15 weeks out of rotator cuff surgery. There are places in this boat that I have not actually seen yet. I had a 19 year old on board for the trip that could get into those spaces and describe for me what was there.

Time for some detective work. Could I hire this work to be done? Yes but there is still no wiring diagram and I would still not understand what I have. Time to get one of those meters that is wireless for continuity.

Hattaras electrical systems can be quite complex. I spent a considerable amount of time on my brothers 52 sport fisher. His has a few transformers installed from new, and could use 50 or 30 amp shore service, 120 or 240 volt. It took some time to figure out all the combinations of switches to make it all work. There might be resources at the factory to help?

 

[twistedtree]

Diagramming it out sounds like an excellent starting point.

 

[socalrider]

No specific guidance other than to be really really careful. You seem to be diligent in your research so you probably know this, but AC is very dangerous compared to DC. When I started digging into my boat's 40 year old AC system I was immediately terrified and pulled the entire thing out based on what I found. I remember you mentioning some ground issues in your DC system, so it's likely there's issues on the AC side as well.

It may well be worth hiring someone to come out and run through this stuff with you - you'll learn a ton, won't get hurt, and will probably get answers and accumulate knowledge 10x quicker that way.

 

[PierreR]

No specific guidance other than to be really really careful. You seem to be diligent in your research so you probably know this, but AC is very dangerous compared to DC. When I started digging into my boat's 40 year old AC system I was immediately terrified and pulled the entire thing out based on what I found. I remember you mentioning some ground issues in your DC system, so it's likely there's issues on the AC side as well.

It may well be worth hiring someone to come out and run through this stuff with you - you'll learn a ton, won't get hurt, and will probably get answers and accumulate knowledge 10x quicker that way.

I am familiar with AC power much more dangerous that this. At the moment, there is no power to me boat in heated storage. I can ask permission to test but not leave power on.
At the moment, I am face palming the DC system. House bank is three 8D start batteries.

 

[socalrider]

I am familiar with AC power much more dangerous that this. At the moment, there is no power to me boat in heated storage. I can ask permission to test but not leave power on.
At the moment, I am face palming the DC system. House bank is three 8D start batteries.

Good deal, carry on then! Agree that diagraming is a great idea. Samsmarine.com is good for Hatt stuff - not sure if an OEM wiring diagram exists for your boat (or how relevant it'd be at this point) but you might find something there.

 

[PierreR]

Good deal, carry on then! Agree that diagraming is a great idea. Samsmarine.com is good for Hatt stuff - not sure if an OEM wiring diagram exists for your boat (or how relevant it'd be at this point) but you might find something there.

An OEM diagram probably does exist. I have not been able to get through the switchboard to anyone at Hatteras. I have not tried to go the Sam's route yet and that is likely to produce something.
In the case of the shore power here, the original diagram is not likely to be correct but would be correct for much of the boat. This boat has undergone few upgrades and the original wiring is largely intact with very few orphan wires just dangling.
There were still things I face palmed. Such as connections of bilge pumps. As usual they looked like they were done in 10' seas on the beam.

 

[Bmarler]

I am familiar with AC power much more dangerous that this. At the moment, there is no power to me boat in heated storage. I can ask permission to test but not leave power on.
At the moment, I am face palming the DC system. House bank is three 8D start batteries.

It was common for hattaras to use 32 volt dc systems. These are quite dangerous as well, so keep your wits about you.

 

[PierreR]

All 12 volt

 

[PierreR]

I will add another red flag. I picked the boat up in fresh water, ran it in salt water around the east coast and back into fresh water. When I pulled the boat for survey the zincs were in good condition. When I pulled it for winter storage the zincs were much more corroded than I was expecting and most need replacement.
The bonding system zincs are in pretty good condition but the running gear and rudders were not.

 

[socalrider]

There were still things I face palmed. Such as connections of bilge pumps. As usual they looked like they were done in 10' seas on the beam.

My bilge pumps were connected with wire nuts. Lying in the bilge.

I found some connections above the helm station which were made by connecting terminals with nuts and bolts just sitting there loose in the compartment. Care seemed to have been taken to ensure that the energized 12v bolts couldn't physically reach the ground terminal so that was a win I guess.

 

[PierreR]

My bilge pumps were connected with wire nuts. Lying in the bilge.

I found some connections above the helm station which were made by connecting terminals with nuts and bolts just sitting there loose in the compartment. Care seemed to have been taken to ensure that the energized 12v bolts couldn't physically reach the ground terminal so that was a win I guess.

Oh yes, marine all the way!

 

[SteveK]

My inverter will pass thru up to 60A, but will only invert 17A, what is your spec.
Overheat could be from loads that draw more than the rated max continuous output of inverter. They will output higher for a short time.

You did not say that you have isolated all inverter load neutral to a separate buss bar.

 

[twistedtree]

My inverter will pass thru up to 60A, but will only invert 17A, what is your spec.
Overheat could be from loads that draw more than the rated max continuous output of inverter. They will output higher for a short time.

You did not say that you have isolated all inverter load neutral to a separate buss bar.

I think he meant "temporary" overload, not "temperature" overload. I scratched my head for a while on that too.

 

[PierreR]

My inverter will pass thru up to 60A, but will only invert 17A, what is your spec.
Overheat could be from loads that draw more than the rated max continuous output of inverter. They will output higher for a short time.

You did not say that you have isolated all inverter load neutral to a separate buss bar.

Opps, kinda wrote that wrong. "Temp overload" is temporary power overload not temperature overload.

I cannot tell you at this point whether I isolated the neutral wires to a separate buss bar. Likely not.

 

[twistedtree]

When on 50amp shore power and the switch in 240 volts, I can measure 240 volts between the two halves of the AC panel and I have all AC units operable. When I am on 30 amp 120v with the switch in 120v I measure 120 volts between the two halves.

I'm not understanding this. Are you measuring 120V L1 to L2? Or are you measuring 120V L1 to neutral (and presumably also L2 to neutral)?


If teh boat was originally equipped with two 30A 120V inlets, then it's reasonable to expect two independent load panels, each powered by one of the shore inlets. Is that still the setup with the new 50A 240V shore inlet, and 30A 120V inlet? Or has the load panel been converter to be a split phase panel?

 

[PierreR]

I'm not understanding this. Are you measuring 120V L1 to L2? Or are you measuring 120V L1 to neutral (and presumably also L2 to neutral)?


If teh boat was originally equipped with two 30A 120V inlets, then it's reasonable to expect two independent load panels, each powered by one of the shore inlets. Is that still the setup with the new 50A 240V shore inlet, and 30A 120V inlet? Or has the load panel been converter to be a split phase panel?

L1 to L2 is 240v, L1 to LN is 120v or L2 to LN is 120v when 50 amp 240 plugged in and power switch is in 240v position.

On your second question I would love it if it were that simple.
With power switch in 240v position and 240 v 50 amp plugged in between L1 and L2 is 240 volts and the air conditioning panel is also 120v
When plugged into single 30 amp cord and the power switch is in 120v, both sides of the panel have the same phase and the air conditioning panel has 120v.
When I have a 50 amp 120v cord plugged in and the switch in 120v I get a single phase between two sides of the panel and the Air conditioning panel gets 120v.
I don't know what I get with the 50 amp 120v cord plugged in and the power switch in 240v. I also don't know what I get with an adapter for two 30 amp shore power to 50 amp 240 at the boat and switch in 240v. Not tried it.
The generator is 12o volts and supplies like a single 30 amp cord but generator puts out 75 amps max.
Panel mains are 30 amp so really, 50 amp is a pipe dream but I get more power for air conditioning because its a separate panel through another fuse and transformer.
Incoming power is a two pole 50 amp breaker to the 15KVA transformer and two 30 amp fuses, one for each of the 5KVA transformers. The green wire on the 15KVA transformer is connected to the case and the bonding system. The green wire from the 5 KVA transformer is not connected to anything. I have never laid eyes on the third transformer. I can hear it buzz behind the stove where the owners manual says it should be. This physically compromised body has not been contorted enough to see it yet.
I will be at the boat tomorrow.

 

[PNW]

Great detective work so far, OP. I am also post-surgery unable to get everywhere, and also going through a new boat of new systems with complexities that are all new to me. I am curious where you got with this in the last couple of months. And hopefully you're feeling a bit more flexible now. I am 6 weeks after hip replacement, myself. But I'm having a lot of fun spending all of my free time on such a beautiful ship.