Heating/Air Conditioning tripping marina shore power pedestal breaker.

[jclays]

My normal shore power hookup is one 30A cord to the boat. it is a 1997 Mainship 350 Trawler. My panel is divided as 2 panels. Panel one and panel 2. I can have 2 incoming shore power cords 30a ea or use one 30A cord and close the parallel switch at the panel to tie both panels together.
Everything worked fine with the panels parallel so long as I manage the load being used on the boat.
I relocated to another marina closer to home. I connected to shore power as described above with one 30A cord. It was cold out so I flipped the switch to turn on my heating in the salon. Upon start up the heater's start up load tripped the marina pedestal . A 30A breaker. I reset it a few times to the same result.
Next I hooked up the 2 power cords with the Y 50A adaptor to the pedestal and the boat. Turned on the heating and also tripped that.
I called the marina maintenance department. They sent a gentleman He checked out the pedestal and said they were good on their end. We plugged in to the next pedestal over with the same results. He told me the problem was my heater.
Next I disconnected from shore power altogether and started up my genset. Turned on the heater and no problems.
Mind you all this time the breakers on the house panels did not trip. only the marina's shore power pedestals.

 

[ranger58sb]

Does this new marina have new power pedestals and the new GFCIs?

If so, it apparently really is likely there's a previously-undiscovered issue with your heating/AC circuit wiring.

If this is the case, see threads about the new GFCI or ELCI pedestals...

-Chris

 

[tiltrider1]

I am not surprised. Your hot water heater pulls 12 amps. Your house probably pulls another 12 amps and when you turn on the heater you pull 15 amps. That’s 39 amps. More than the pedestal can handle.

 

[jclays]

I am not surprised. Your hot water heater pulls 12 amps. Your house probably pulls another 12 amps and when you turn on the heater you pull 15 amps. That’s 39 amps. More than the pedestal can handle.

This is only with the air/heater.
The fridge is DC only
Water heater is not used unless I am staying on board.
House lights are Led and not on in the day time.
The only thing on is the battery charger.
Had no issues in the previous marina.
No issues when I tested with generator only. Heating ran fine.

 

[jclays]

Interesting reading on the threads regarding GFCI pedestals. Sounds like I might possibly have and Issue. I'll be needing a marine electrician to help me check this out.
I'll pull into another slip in this marina and plug in. If I trip the breaker with my heating/air-conditioning then I'll be sure the problem is mine. If all works then possibly the pedestal at my slip has the issue.

 

[jgwinks]

Some of the other threads have blamed the aircon's water pump for this issue. Apparently prone to leaking AC current to ground via the water in the pump. Water heater as well with the same problem, but if the WH breaker is off then it's eliminated. The new dock pedestals with ELCI see this ground fault and trip. The onboard genset probably does not have ELCI so nothing to trip. Regular breakers trip on overload, not ground fault, so you never know there's a problem till you try to connect to an ELCI. So you need to know if it was an ELCI or regular breaker that tripped. Overload or ground fault, two completely different problems and fixes.

 

[Scottwb96]

definitely what others have said about GFCI...

couple of ways to do some quick troubleshooting (narrow it down).

1. with ALL breakers off, when you plug in, does the shore trip?

2. if it does, you'll need to start with the plug to panel wiring. I have also read that the little LED lights on shorepower cords can actually cause JUST ENOUGH imbalance in the power return to trip it (usually on cheaper, no-name cables).

3. if not, slowly start turning on breakers, on/off 1-by-1. You may find 1 culprit, you may find a few. Inverters, neutral connected to ground has been a big one for years... microwaves/appliances, hot water heater, and your a/c water pump as you have already read.

Once you narrow it down to 1 or many, you can either trace the wires and correct them, or at least get an electrician on the right path a little faster, save a few bucks...


Isolation transformer will also help with all of these issues as well. Depending on your setup and your ability to troubleshoot on your own, the I.T. may be a least costly option than troubleshoot/rewire entire electrical system. Not saying you shouldn't also locate the problem, but just throwing that out there...

 

[jclays]

I’m not familiar with isolation transformation. Can you tell me more?

 

[JohnEasley]

Happened to us when we pulled into Marathon Marina in the Keys. They had just redone all of their pedestals. Their electrician said almost every boat tripped them at first and almost all of them turned out to be how the inverter was wired. I checked our inverter manual and there was actually a section in the installation guide that touched on this and told which wire to disconnect to fix it. Don't have the info anymore but I would recommend starting there. Appears to be somewhat common.

 

[Scottwb96]

Here's a few articles... Just google Marine Isolation Transformer...

https://www.boatus.com/expert-advice/expert-advice-archive/2015/july/isolation-transformers

https://stevedmarineconsulting.com/wp-content/uploads/2019/12/ShorePowerTransformers181-04.pdf

 

[jclays]

Happened to us when we pulled into Marathon Marina in the Keys. They had just redone all of their pedestals. Their electrician said almost every boat tripped them at first and almost all of them turned out to be how the inverter was wired. I checked our inverter manual and there was actually a section in the installation guide that touched on this and told which wire to disconnect to fix it. Don't have the info anymore but I would recommend starting there. Appears to be somewhat common.

Thanks for the input but I do not have an inverter. Just a charger

 

[jclays]

Would the thru hull bonding have anything to do with this?
I have found all of them disconnected and safe ended by the PO. I don’t know why you would do that.

 

[fgarriso]

Go back to the switch panel and turn everything off.

While your at it put the amp meter clamp on the incoming shore power hot wire and see if there is any current there with all of the switches off.

Now put the clamp amp meter on each line and turn the switch on to see what the amp draw is.

 

[jclays]

Go back to the switch panel and turn everything off.

While your at it put the amp meter clamp on the incoming shore power hot wire and see if there is any current there with all of the switches off.

Now put the clamp amp meter on each line and turn the switch on to see what the amp draw is.

Access to the back of my switch panel to clamp each hot lead is pretty hard. the panel is set into the wall. my only access is to unscrew the face cover of the panel. Last time I checked out the rear of the panel there was not much slack in the wiring to properly pull the cover out and clamp anything.

 

[tiltrider1]

Way too much missing information. What amperage are your breakers, I assume one 30a breaker for each panel. This Y is it 50a 125/250v at the dock and two 30a 125v outlets at the boat. Or is it two 30a 125v at the dock and one 50a 125/250v at the boat or some other Y. Are the dock pedestals GFI or not? What is the capacity of the generator? My generator puts out 120a or 60a on each of two legs. I could never pull that much power from a dock.

 

[jclays]

Way too much missing information. What amperage are your breakers, I assume one 30a breaker for each panel. This Y is it 50a 125/250v at the dock and two 30a 125v outlets at the boat. Or is it two 30a 125v at the dock and one 50a 125/250v at the boat or some other Y. Are the dock pedestals GFI or not? What is the capacity of the generator? My generator puts out 120a or 60a on each of two legs. I could never pull that much power from a dock.

Dock pedestal is one 50A and one 30A
50A y adaptor has 2 ea 30A 125V . Attached is 2ea 30A 125v cords going to 2 30A input receptacles on the boat.
generator is a 9000kw Onan. Don't have the specifics on it.

 

[OldDan1943]

I am not surprised. Your hot water heater pulls 12 amps. Your house probably pulls another 12 amps and when you turn on the heater you pull 15 amps. That’s 39 amps. More than the pedestal can handle.

I have a tendency to agree with titrider, if you have a single 30amp feed.
I have 2X30amp feed. One feed for the house and one feed for the 2 reverse cycle A/C.
An amp meter will give you a good indication of amperage draw.
I was used to 2X50 amp service. (sad story) now my boat is a 30 amp boat.
I had a 2nd amp meter put in the galley..... trust me, I have almost perfected the "30 amp dance".

Guess you could confirm the amperage draw by watch your amp meter as you load it up. I am guessing you do not have an electric stove because you have 1X30amp service.
Turn off your water heater, turn on one A/C in the heat mode, watch the draw.... turn on the 2nd A/C .... watch them cycle, I suspect you will see your 30amp service is almost maxed out.
When I am approaching the upper limit of my house 30amp service, I 'dance' over and shut off the water heater.
Watch for cycling loads.
IF what I have asked you to do, gives you good feed back, ask your A/C man if 'soft starts' on the A/Cs will prevent or reduce the tripping.
My question is why is it tripping the pedestal breakers instead of the breakers on the boat.

 

[tiltrider1]

Dock pedestal is one 50A and one 30A
50A y adaptor has 2 ea 30A 125V . Attached is 2ea 30A 125v cords going to 2 30A input receptacles on the boat.
generator is a 9000kw Onan. Don't have the specifics on it.

Industry standard would be a 50a 125/250v socket and a 30a 125v socket. However, it is important to confirm that it is not a 50a 125v socket. If it is a 50a 125v then you will have less power than 2 30a circuits can pull. Your generator is 37a per leg assuming it is wired correctly.

At this point we need to confirm if your pedestal is GFI protected or not.

 

[jclays]

I have a tendency to agree with titrider, if you have a single 30amp feed.
I have 2X30amp feed. One feed for the house and one feed for the 2 reverse cycle A/C.
An amp meter will give you a good indication of amperage draw.
I was used to 2X50 amp service. (sad story) now my boat is a 30 amp boat.
I had a 2nd amp meter put in the galley..... trust me, I have almost perfected the "30 amp dance".

Guess you could confirm the amperage draw by watch your amp meter as you load it up. I am guessing you do not have an electric stove because you have 1X30amp service.
Turn off your water heater, turn on one A/C in the heat mode, watch the draw.... turn on the 2nd A/C .... watch them cycle, I suspect you will see your 30amp service is almost maxed out.
When I am approaching the upper limit of my house 30amp service, I 'dance' over and shut off the water heater.
Watch for cycling loads.
IF what I have asked you to do, gives you good feed back, ask your A/C man if 'soft starts' on the A/Cs will prevent or reduce the tripping.
My question is why is it tripping the pedestal breakers instead of the breakers on the boat.

All this occured with only turning on the heater/AC in this marina.
I did not have this problem last month in my previous marina. And it is a 6 year old marina.
I do not live on my boat so it sits in the slip with everything turned off except the battery charger.
I came to the boat yesterday and turned on the heat as i always did in the other marina ( same cord same set up) and Im blowing marina pedestal breakers...

 

[jclays]

Industry standard would be a 50a 125/250v socket and a 30a 125v socket. However, it is important to confirm that it is not a 50a 125v socket. If it is a 50a 125v then you will have less power than 2 30a circuits can pull. Your generator is 37a per leg assuming it is wired correctly.

At this point we need to confirm if your pedestal is GFI protected or not.

I will take a picture of the name plate and post it. Ill need your help posting pictures since I have not posted pictures before.

I am just baffled that I did not have this problem last month in the marina I left. It too is only 6 years old after its complete rebuild. Everything on board is always turned off except the battery charger which is running with no issues. I come on board and flip on the heat and POP!

 

[OldDan1943]

All this occured with only turning on the heater/AC in this marina.
I came to the boat yesterday and turned on the heat as i always did in the other marina ( same cord same set up) and Im blowing marina pedestal breakers...

What's your amp meter tell you when you turn it to heat?
Do you have the same problem if you turn it to cool?

 

[ranger58sb]

I am just baffled that I did not have this problem last month in the marina I left. It too is only 6 years old after its complete rebuild. Everything on board is always turned off except the battery charger which is running with no issues. I come on board and flip on the heat and POP!

In 2017/2018 we went south (previous boat) and had no problems. In 2019/2020 (same boat), two of the same previous marinas along the way had replaced dock pedestals, and we immediately tripped at those.

When we brought the current boat (which has an isolation transformer, and no inverter as yet) up here this past Summer, we didn't trip anywhere, including those same two marinas and other along the way that had also since updated their pedestals.

-Chris

 

[jclays]

Industry standard would be a 50a 125/250v socket and a 30a 125v socket. However, it is important to confirm that it is not a 50a 125v socket. If it is a 50a 125v then you will have less power than 2 30a circuits can pull. Your generator is 37a per leg assuming it is wired correctly.

At this point we need to confirm if your pedestal is GFI protected or not.

It is GFI protected.
50A 125/250v, 30A 125v.

 

[jclays]

Played around today with the breakers and the only equipment tripping the pedestal breaker was the rear heater/air conditioning unit.
I noticed that the battery charger was also on the same side of the panel that fed the rear heat unit.
I turned off the battery charger and turned on the rear heat unit. It worked no issues. I then turned on the battery charger and it held.
If I have turn the battery charger off before I turn on the heater unit then I can turn the battery charger back on . It all holds.

 

[Iggy]

I had the same problem. The breaker kept popping on the power station. But I am in a yacht club and do a lot of volunteer work there. I just knew it was not my boat. I went into there marina locker and took a whole new 30A assembly and installed it. The problem went away. The wires were getting corroded so voltage went down and amps went up.

 

[Bacchus]

Played around today with the breakers and the only equipment tripping the pedestal breaker was the rear heater/air conditioning unit.
I noticed that the battery charger was also on the same side of the panel that fed the rear heat unit.
I turned off the battery charger and turned on the rear heat unit. It worked no issues. I then turned on the battery charger and it held.
If I have turn the battery charger off before I turn on the heater unit then I can turn the battery charger back on . It all holds.

One of the common causes of GFCI / ELCI trips are an onboard connection between ground and neutral. Being that you have isolated the source of your problems I would spend some time looking at the connections to these devices... any evidence of the neutral being connected to the ground / case ground?
I believe the tightening of the GFCI / ELCI trip levels and time delay associated with these was 2017. If that is correct, a 6 year old marina may not have been designed & built to the latest / more stringent requirements.

References:
https://www.marinadockage.com/technical-bulletin-electrical-changes-marina-code/

Troubleshooting: Electrical Safety

 

[OldDan1943]

Played around today with the breakers and the only equipment tripping the pedestal breaker was the rear heater/air conditioning unit.
I noticed that the battery charger was also on the same side of the panel that fed the rear heat unit.
I turned off the battery charger and turned on the rear heat unit. It worked no issues. I then turned on the battery charger and it held.
If I have turn the battery charger off before I turn on the heater unit then I can turn the battery charger back on . It all holds.

Will a soft start on the connpressor help?

 

[Bacchus]

Will a soft start on the compressor help?

Only if it is tripping on overload and not GFCI. From info provided I doubt it is overload but it would require confirmation using a clamp on A meter on the main feeds as items are started to see if there is A draw even approaching the breaker limit.

 

[tiltrider1]

My interpretation of jclays's post is, heater only does not trip breaker, battery charger only does not trip breaker, the combination of battery charger and heater starting up trips the breaker.

This suggest that there is not a neutral/ground issue but an issue with too many amps on start up. Most likely, the old dock had slow trip breakers that could handle the surge of the start up and the new breakers can not handle it.

I would need to know more about your battery charger. It is possible that we can turn down the battery charger and prevent the issue or you can just turn the battery charger off when you need heat.

 

[OldDan1943]

Only if it is tripping on overload and not GFCI. From info provided I doubt it is overload but it would require confirmation using a clamp on A meter on the main feeds as items are started to see if there is A draw even approaching the breaker limit.

Dont have a clamp meter, watch the amp meter on the boat.