Heating/Air Conditioning tripping marina shore power pedestal breaker.

[jclays]

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.

If it was due to overload wouldn’t the house breaker trip before the source pedestal?

 

[jclays]

I was told by the other tenants that the pedestal breakers are very sensitive

 

[C lectric]

*****If it was due to overload wouldn’t the house breaker trip before the source pedestal?******

If they are both rated the same then NO. One unit will be faster than the other even under the same overload. Called racing breakers or fuses. This comes down to ageing and also mfg. tolerances even from the same mfgr.

 

[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.

Will a soft start on the connpressor help?

If my previous guess re GFCI is wrong and it really is overload, sequencing the start will likely be a temporary fix. When the heat (assuming AC/heat pump) cycles off then on you will have the same start up conditions that previously tripped. Batty charger on and heat starts. It may depend on what state the charger is in as once it goes to float the amp draw will be very small vs bulk charging.
Ig it is overload OldDans suggestion of soft start could be a solution worth considering. I'd be verifying the actual amp draw under various conditions that trip / do not trip.

 

[tiltrider1]

Knowing your actual amp usage is an important part of the puzzle. So important that I went on eBay and bought 2 digital amp meters that I have permanently installed on both L1 and L2. This way I can monitor how much amperage each line is using at all times.

https://www.ebay.com/itm/2722046909...rTqD%2BvWkfAFgIT|clp:2334524|tkp:BFBMwtD8orhf

 

[ranger58sb]

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.

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 was told by the other tenants that the pedestal breakers are very sensitive

Knowing your actual amp usage is an important part of the puzzle.

Should be easy enough to look up amp usage for both battery charger in bulk/absorption and float, and AC/heat unit at startup.

Might be possible to move that battery charger to the other circuit?

-Chris

 

[jclays]

I’ll have to get a couple amp meters boat is only equipped with volt meters.

 

[SteveK]

One item not discussed is the shore cable connection at the boat. The source of heat corrosion there and possible leakage neutral to GND. One of the reason the smart plugs became commonplace.

 

[EngNate]

Yes, it does sound like a ground-to-neutral connection. Fault current will rise in proportion to total load, and will also be affected by the resistance of the G-N circuit as well as its location in the system. This problem can be caused by a Reverse-Polarity warning lite, especially the larger jewel lens panel indicators; Also polarity-trip circuit breakers which are found on a few boats. Find it using an ohmmeter between the Ground and Neutral busses at the main panel - Resistance here should be 100K Ohms or higher.

 

[Helmsman]

With the sequence of events you listed, it is the combination of the charger being on, and the HVAC starting up that trips the breaker. The reverse is not true. So the combination of those two activities is popping the breaker. On another website, an individual had the same problem. HVAC turning on tripped the breaker. Only at new GFCI docks. He suspected that it was the new GFCI’s. After two weeks of going back and forth, he decided to try replacing his 30 amp breaker. It was fixed.

A 30 amp main breaker is relatively inexpensive. I would replace the suspect one, that solved his problem. In fact, I would replace both. Make sure when you do that the power and the inverter is OFF. Turn the battery feed to the inverter off after turning off the battery switch. Disconnect the SP cables.

If you don’t want to take that step first, then amp measurements are necessary. Check the pedestals, check your cables with them hooked to the pedestal but not to the boat, check the inbound feeds in the panel (if you are not very familiar with AC electrical, I would have an electrician look at it. You can hurt or kill yourself) Recreate the conditions and check the amperage at the breaker. If it is within specs but the breaker pops, then it is probably the breaker.

With these kind of problems, best to eliminate variables from the pedestal into the boat, one step at a time.

 

[CharlieJ]

@EngNate #39:

Resistance here should be 100K Ohms or higher.

Good info with one caveat, N/G resistance >100k Ohms would certainly be excellent but the actual requirement (ABYC) is for N/G resistance to be >25k Ohms and is sufficient to preclude tripping a pedestal ELCI.

 

[CharlieJ]

Here is a very long blogpost that I consider a textbook on the subject:https://tinyurl.com/2p8rcesx

As others have cautioned, be extremely careful as you will be working on energized components and wiring that is a definite shock hazard.