ELCI breaker issue

[tiltrider1]

First, the problem has been resolved. I am trying to understand what was truly causing the problem.

The ELCI worked correctly for years. One day it tripped. It would not reset. If the breaker at the pedestal was turned off the ELCI would reset. No surprise as there was no power. The power could then be turned on and all was fine, for a random amount of time that could be anywhere from seconds to days. If the ELCI was turned off it would not reset unless power was turned off at the pedestal first.

I then tried turning off all the breakers on the Boats panel. This allowed me to reset the ELCI with the pedestal power still on. I could then turn on each breaker except the Engine room Outlet circuit. Turning that breaker on would cause the ELCI to trip. However, I could leave that breaker on, turn the power off at the pedestal, reset the ELCI and then turn the power on at the pedestal and all would be fine, for a random amount of time.

There was a small battery charger plugged into one outlet. I used an extension cord to plug it into a different circuit. This seemed to solve all the problems. At this point I suspected that the GFI outlet had a failure so I replaced the outlet with a standard outlet for testing. As soon as I plugged the charger back into the new outlet the ELCI tripped.

Ok, its not the charger and its not the outlet. It must be the wire. I ran a new power, neutral, and ground wire to the outlet. I was able to disconnect the the old wires. This solved the problem and the ELCI is functioning as it should.

I was able to fully remove the power wire. No marks and no breaks. I am not able to remove the neutral or the ground wire to inspect them. This is where I am at a loss. If the ground and the neutral were to come in contact the ELCI would trip and nothing would allow you to reset it until that connection was broken. What combination of failure in these two wires would explain the ELCI's behavior.

 

[Barking Sands]

I was able to fully remove the power wire. No marks and no breaks. I am not able to remove the neutral or the ground wire to inspect them. This is where I am at a loss. If the ground and the neutral were to come in contact the ELCI would trip and nothing would allow you to reset it until that connection was broken. What combination of failure in these two wires would explain the ELCI's behavior.

It doesn't have to be a hard fault. I would guess the two wires rubbed through the casing in close proximity and has a small amount of current passing from one to the other when there may be some additional moisture present. You may be able to get a good multimeter and set it to ohm and just put each probe on both wires. It should be completely open. If the wire hasnt been disturbed from its partially failed state you may read slight continuity. Did you have any water ingress recently? You did have some temp changes I am sure?

One technique used on aircraft for intermittent problems is the use of freeze spray. many times a switch or very sensitive LVDT or RVDT will act up on a flight but never be duplicated on the ground. Many times the only variable is temperature. So a common tactic would be to shoot freeze spray at the sensor or switch to simulate the cold temps at altitude so we can duplicate the issue on ground.

Obviously you have fixed the issue, so I doubt you will spend time on it..but some careful set up and investigation could probably uncover the issue. It may have even been at the other end...or anywhere in between.

Even worse is when you have this issue, read some very high ohms in a circuit, wiggle and tug on some wires in the hopes it reveals itself even more, only to disappear forever...lol.

 

[SteveK]

I like a mystery. Fill in some details

However, I could leave that breaker on, turn the power off at the pedestal, reset the ELCI and then turn the power on at the pedestal and all would be fine, for a random amount of time.

Was anything plugged in during this random time?

As soon as I plugged the charger back into the new outlet the ELCI tripped.

When you had the outlet and wires out did you inspect those for any breaks?
Is the receptable box metal or plastic?
The wire securing part of the box could have crushed/split the wire encasing.

I am not able to remove the neutral or the ground wire to inspect them.

What? Did you only replace the hot wire and not all three?

 

[tiltrider1]

Was anything plugged in during this random time?

Yes, a battery charger on the offending circuit. Other appliances on other circuits.

Is the receptable box metal or plastic?
The wire securing part of the box could have crushed/split the wire encasing.

Box was plastic. All wires looked visually correct.

What? Did you only replace the hot wire and not all three?

All three wires were replaced. Unfortunately only the power wire could be completely retrieved for inspection. 4’ of the neutral and ground could not be retrieved. They were capped off at both ends.

If I could have retrieved all of the neutral and ground I might have discovered chafing our burned insulation or maybe something else. Still can’t explain why the ELCI behaved inconsistently.

Barking Sands suggests that two chaffed neutrals could cause the random tripping issue but what explains the inconsistency with the resets?

 

[SteveK]

In marine wires all three strands are insulated compared to house wiring where ground is bare. Any breaks in the wire strands would arc and quickly become open. I think we have ruled out vibration causing ground/neutral bares to touch.

If the charger was plugged in then it is still suspect. Inverters are found to be at fault when not switching the ground/neutral fast enough.
Does the charger not have an internal on/off to stop charging when programmed voltage is reached? That could be faulty and source of irregular trips on ELCI.

 

[Barking Sands]

In marine wires all three strands are insulated compared to house wiring where ground is bare. Any breaks in the wire strands would arc and quickly become open. I think we have ruled out vibration causing ground/neutral bares to touch.

This is not always true

 

[SteveK]

This is not always true

Any breaks in the wire strands would arc and quickly become open.
Then it could have been a vibration break on original wires.
But then it could be the wires going into the charger as well.

 

[O C Diver]

On my boat the first receptacle was a GFI. Then down stream of the first receptacle, all the others are regular receptacles as they are protected by the first (GFI). So the question is, was the alternate receptacle you plugged the battery charger into, down stream from the GFI receptacle it was originally plugged into, or a different circuit?

Was the original circuit wire tinned or copper? Were the original circuit wires stranded or solid? If stranded, were there crimp connectors on the connections between the wires and GFI receptacle?

If I were to hazzard a guess, it would be a bad connection on the ground or neutral at either end of the circuit.

Ted

 

[Barking Sands]

Any breaks in the wire strands would arc and quickly become open.
Then it could have been a vibration break on original wires.
But then it could be the wires going into the charger as well.

Yeah...95 times out of 100 the issue is at the ends not in the middle.
But my objection to the statement is mainly from how many times I have seen surface corrosion and/ or moisture cause these kinds of issues where it creates a very slight pathway. This kind of scenario typically affects very sensitive electronics without arcing or full failure. And it is many times intermittent.

 

[Iggy]

I understand the problem was fixed.

What type of charger was in use. A marine or car charger. Most car chargers can cause this problem. I have heard of it but not sure why. It may be how the charger is grounded internally.

 

[tiltrider1]

The Battery charger was moved to a different circuit. A hair drier was used to test the outlet. The hair drier had the same affect as the battery charger. At this point the Outlet itself became suspect and it was replaced with a new outlet. This had no affect. That is when I perused the wiring. Afte running new wires the original outlet was reinstalled and the battery charger plugged back in. After running new wires the ELCI started to behave in the correct fashion. The charger is a marine charger but only a 10 amp charger.

This boat does not chain outlets together. It uses a junction box to supply sperate wiring to each outlet. Moving the battery charger to a different outlet on the same circuit also appeared to correct the issue.

So, we know the issue is not related to the charger or the GFI outlet. We know its related to either the ground wire or the neutral wire. I doubt the ground wire is involved as any continuity between the ground and the neutral would have prevented the ELCI from ever resetting. Temperature changes sounds like an explanation but I shouldn't have been able to reset the ELCI until there was another change in temperature. Some leakage between the neutral and a different neutral such as Line 2's neutral or a neutral not on the Inverter neutral buss could possibly explain it.

I certainly wish I could have pulled the neutral and ground wire out to inspect.

 

[O C Diver]

What about tinned wire and whether there were crimp wire connections between the wire and the receptacle?

Ted

 

[Barking Sands]

I would start by putting an ohm meter on your remaining nuetral and ground from either end. See if you get any reading between the two. Then measure from the old nuetral to a good ground, since your old ground is now isolated.

 

[Fleming]

I think what a lot of you are missing is that you don't need a direct short. You don't need wires touching wires. Using Ohm's law you only need 4,000 ohms resistance between the conductors to trip a 30mAmp ELCI.
Insulation breaks down over time. Moisture gets into places we don't expect. Had you turned the power off, checked resistance to ground at that outlet, I suspect you would have found less than 4,000 ohms.

 

[rslifkin]

I think what a lot of you are missing is that you don't need a direct short. You don't need wires touching wires. Using Ohm's law you only need 4,000 ohms resistance between the conductors to trip a 30mAmp ELCI.
Insulation breaks down over time. Moisture gets into places we don't expect. Had you turned the power off, checked resistance to ground at that outlet, I suspect you would have found less than 4,000 ohms.

Agreed. I had to replace the burner coils on the stove on my boat when I got it. Any time you used them on high, it would trip an ELCI dock breaker. Turned out the old burner coil insulation was breaking down and when they got hot enough they'd leak a bit of current to the stove casing and cause the trip.

 

[SteveK]

High ER humidity, may have wicked into wires now replaced.

 

[tiltrider1]

What about tinned wire and whether there were crimp wire connections between the wire and the receptacle?

Ted

Boats original wiring was not tinned. Yes there were crimped connectors used between outlet and wire.

 

[tiltrider1]

I would start by putting an ohm meter on your remaining nuetral and ground from either end. See if you get any reading between the two. Then measure from the old nuetral to a good ground, since your old ground is now isolated.

I have thought about this. Right now my time is being sucked towards a malfunctioning car.

 

[O C Diver]

Boats original wiring was not tinned. Yes there were crimped connectors used between outlet and wire.

You may have experienced some increased resistance. Consider all the crimp connectors and any junctions in the circuit from the breaker to the GFI. Without getting to far into the weeds, you have copper wire and I'm assuming unsealed common crimp connectors. Probably not an issue until you add an ultra sensitive ELCI breaker.

Ted

 

[Bmarler]

Standard ohm meter may not have enough power to really check for insulation breakdown. I use a megger for that.

 

[NoRain]

You may have experienced some increased resistance. Consider all the crimp connectors and any junctions in the circuit from the breaker to the GFI. Without getting to far into the weeds, you have copper wire and I'm assuming unsealed common crimp connectors. Probably not an issue until you add an ultra sensitive ELCI breaker.

Ted

GFI is *much* more sensitive than an ELCI - 5mA vs 30mA to trip.

 

[tiltrider1]

Well, life has me busy doing other things right now. However, since capping off the old wires and running new ones there have been no issues. The ELCI continues to function predictably.

It was the illogical behavior of the ELCI that had me puzzled. I still can’t explain why it would reset one way and not the other. It should have either reset Both ways or neither way. The closest I can get to an explanation is that two neutrals made contact and one was on the inverter buss and one was not.