Electrical Mystery (120 volt)

[SteveK]

The original schematic paths make sense except the neutral from generator.
The gen neutral goes to the left (AC) switch but it also should go to the right (service) switch like the hot (red wire) in the terminal on switch from the neutral buss at far right. There should not be a wire from neutral buss to (service) switch.

As you said the ground and neutral are connected at the generator but the neutral from the generator is only going to the AC and nothing to the receptacles because of that loop I mentioned before if it is wired as the schematic shows.

ETA: your post 19 shows neutral going to both switches.

 

[Roger Long]

The original schematic paths make sense except the neutral from generator.

Damn, you're good. I screwed that up. Sorry to have wasted your time on that issue. Here is the proper schematic. The generator shows proper circuits when running so I've been focused on the shore power circuits and missed that.

 

[SteveK]

OK then, is there still a problem to resolve?

 

[Roger Long]

OK then, is there still a problem to resolve?

Now that I've fixed my schematic "typo", no. Last test on the boat, everything worked and tested properly.


I have to always set both transfer switches the same way, which is what I have always done. As long as I do that, and have either a "Y" or second cable on the AC plug, the outlets find a neutral path I still can't clearly identify. It's probably in the rather complex AC wiring. So, I'm simply going to disconnect the neutral side of that system and add the wire shown here to provide a clear and proper path for the neutral from the AC plug, a quick job. Down the road, when I restore the AC system, I'll get the shore power plug neutrals separated.



Thanks for your sharp eyes and all your help.

 

[Roger Long]

It seems so obvious now when I use the graphic tools to trace the circuit instead of trying to do it in my head.

With a cable on the Ship Service plug and that circuit active, the AC cum Outlet circuit neutral has a path back to shore. Turn the transfer switch or the Ship Service master breaker to "Off", and the neutral side is just hanging out there.

It works but all the current from both circuits is going through that single pin and cable. That can't be good but I'll fix it ASAP by removing the neutral wire to the unused AC units and connecting that terminal to the neutral buss.

 

[Greg QS]

Went through you post several times. Please clarify the problem. Are you having a problem plugging in the boat to new electrical service at a marina on an old boat? The new maria codes are for "afgfci" . It is a gfi and an afci combined. A verry common problem to have an old boat trip this stuff.
Gfi detects problems in the ground/ neutral system.
afci detects the current return from load to neutral

gfi problems normally are reversed polarity or, common neutral /ground buss or shared neutrals between circuits.

afci problems are normally with the neutral system, all you need is a little corrosion or loose connection on any neutral in the system. Ships transfer switches, breakers that switch neutrals , cords, plugs, It can even be anything you have plugged in in the boat, tv, stereo , anything.

For the afci, Think of power this way, (over simplified), what goes down the load must return down the neutral wire. The afci breaker measures this current in mili amps. If there is just the smallest difference the breaker trips. They are so sensitive you cannot even measure it on you typical electrical digital meter. If there is corrosion on the load you still get the same return on the neutral. This is why you need to key in on the neutral connections.

 

[Roger Long]

I know this boat will never work on shore power in a marina with the newer afgfci pedestals until I do some extensive rewiring. Fortunately, we mostly anchor out and prefer older funky marinas.

I never would have discovered or raised the issue if I hadn't been testing the outlets with the Ship Service side inactive. That is never the case when we are plugged in. I think I have learned though that I'm running two circuits worth of load through one circuit's neutral and can fix that easily. Thanks to all who have responded, I've learned a lot.

 

[Turtle Blues]

Upgrading the boats shore power connection to a 50a 125/250 will work inexpensively for most situations. The 50A cord set consists of L1,L2,Neutral and Ground back to the pedestal. The drawback is now needing a 50A pedestal.


Add: It also will give you the option of going to a 230V AC if your generator also supports it.

 

[SteveK]

I know this boat will never work on shore power in a marina with the newer afgfci pedestals until I do some extensive rewiring. Fortunately, we mostly anchor out and prefer older funky marinas.

I never would have discovered or raised the issue if I hadn't been testing the outlets with the Ship Service side inactive. That is never the case when we are plugged in. I think I have learned though that I'm running two circuits worth of load through one circuit's neutral and can fix that easily. Thanks to all who have responded, I've learned a lot.

MY Bad. I thought your schematic was exactly how the wiring was and we were sorting it out. It appears this was not the case and the issue is not the schematic but the actual wiring which you have yet to trace.
I will leave you with one last thought, keep the air conditioning circuit off until all the service runs test correctly. Neither the hot, neutral or ground should come from the AC 30 amp plug.

 

[Roger Long]

Just made the change discussed above and everything tests and works perfectly in every combination of switches and shore power connections as well as on generator. We still won't be able to use afgfci pedestals but we probably wouldn't be able to anyway on a boat this old until a major rewiring.


This is final schematic:

 

[rslifkin]

Just made the change discussed above and everything tests and works perfectly in every combination of switches and shore power connections as well as on generator. We still won't be able to use afgfci pedestals but we probably wouldn't be able to anyway on a boat this old until a major rewiring.

As far as GFCI shore power, you may or may not have major issues. No issues with the original wiring on my 1986 boat. It's possible you may find more issues, but you may also find that the combined neutral bus is the only thing preventing it from working.

As a note, for anyone with an electric stove, if you trip a GFCI shore breaker when a stove burner is on high, replace the burner elements. When they get old, the insulation sometimes gets leaky (worse the hotter the elements are), so the stove can cause ground faults on higher heat settings.

 

[Roger Long]

As a note, for anyone with an electric stove, if you trip a GFCI shore breaker when a stove burner is on high, replace the burner elements. When they get old, the insulation sometimes gets leaky (worse the hotter the elements are), so the stove can cause ground faults on higher heat settings.

Thanks. Good tip. A primary driver of the change that started all this was getting our portable heaters on the separate circuit to avoid tripping the Ship Service breaker and shutting the stove off suddenly when cooking in cold weather. Usually everything would be fine with one heater going and then the hot water heater would come on...

 

[jimL]

Roger, I'm glad it all worked out for you, and it was nice meeting you today on the dock at Donovan's Shady Harbor - Jim