Scary Breaker Trips

Barabus said:

How do people monitor there loading? Do you run a amp measuring clamp and just turn items on and off to get the draw? Or is there a table of common loads? Like on marine ac unit is xxxx Watts? Is there something I could hard wire into my 120v system that is like a Killwatt meter for the boat? My main panel only has voltage meter FYI.

Click to expand...

Here is what I have added to my boat it's the blue back-lighted rectangle above the water tank gauge. I think it was 13 bucks on eBay.

Don't forget, that you have a variety of choices for the element in the water heater. I am running a 1000-Watt element, down from the 1400-Watt element I found in there.

Barabus said:

How do people monitor there loading? Do you run a amp measuring clamp and just turn items on and off to get the draw? Or is there a table of common loads? Like on marine ac unit is xxxx Watts? Is there something I could hard wire into my 120v system that is like a Killwatt meter for the boat? My main panel only has voltage meter FYI.

I have a shunt on my house bank connected to monitoring system. Measures amps in and out real time. Very useful

Click to expand...

This is what I did and it is probably wrong but I work with what I currently have:

Well, to figure out my loading on the 12 volt stuff I cheated and noted the amp draw on unloaded system. Then I turn on something and see the amp draw. Then I turn it off. Note that motors like your bilge pump have like a peak startup draw then a "steady" draw so you need to note both. I tracked down all the 12 volt and have a chart in my log book of the boat which has the amp draw for each 12 volt thingy. (note my use of technical terms, it is a programmer thing....). With this information I can plot how I am drawing down my batteries.

Now, for my AC stuff, I read the brochures for the stuff that still had documentation, (but the PO bought the boat from an estate no a LOT of maintenance and other records were missing). For this things I did not know, I made sure all stuff was off and I turned on the thingy and noted the initial draw on the amp meter on my panel and then the steady draw. Again, somethings change for example my AC starts with a pull then steadies but then at 1 minute draws a pull again when the condensing unit cuts in. I made a chart of all these things in the log book.

So, the lady and I , and the cats, play power managers as we are hooked to shore power all the time as we are living on the boat whilst we build the house. It is fun and you learn a lot about amps and watts and volts, oh my.

We were not doing a really good job as we were getting to close to the limit, now we are better power rangers than before. Plus new chords and one new breaker!

rgano said:

Here is what I have added to my boat it's the blue back-lighted rectangle above the water tank gauge. I think it was 13 bucks on eBay.

Click to expand...

I saw those and wondered if they really worked, if you are happy I think I will order one too. I have monitors on the charger(s) but they just tell current load , DC, and only work when charger is on. I want something that accumulates my outgoing to I can see %, but I do not need it for a few months as we are tied up building house so always on shore right now.

Free breaker lesson.

Terminology - Breakers are; open, closed, or tripped, never “on or off”.
They do not know if they are “powered” on not.
By design breakers are only good for one full rating trip.
After that the breaker is considered out of spec.
This usually melts the contacts or weakens the bimetallic in the breaker.

A therman overload, as this was, is a time based trip depending on the overload severity. Resetting the breaker just shortens the trip time by how cool it got while tripped. I have seen them trip and rest so often the literally blow up in hand while being reset.

So a breaker trips faster the more loaded it is, or has been.

As a note, most breakers can begin to start their timed trip at 80% of rating. So a 30A breaker could start it’s count down at 24A, but it might take a week to trip.
This is too allow for manufacturing tolerances. Two identical 30A breakers each with it’s own trip rating.

A resistive load, hair dryers, lights, etc. can creep up on a breakers rating closely. But an inductive load; A/C unit or fridge will spike the current 6-8 times running current at starting up. The breaker will allow for this short duration spike, as it is usually much less than a second, then cool down.

So if able, start the inductive loads first, then resistive.

If a breaker trips on a short circuit it is considered dead by the professional industry, but not local electricians. On a short circuit, current, (100-1000 times), is so high it blows the contacts in the breaker apart magnetically. The main job of the breaker then is; extinguish the electrical arc, keep itself together mechanically.

The small breakers on boats are fairly robust, they see little current cause the boat electrical system is relatively small and contained. The only place you have real destructive power is electrically near the genset and shore power.

The genset running can generate a tremendous amount of magnetic power, and the pedestal has the power company behind it.

As a note, always protect your genset first with fuses versus breakers. Fuses should be specially rated and very fast acting, and will protect the generator wiring and insulation from getting hot. You typically will not get these fuses without special ordering them. Same for battery chargers and inverters.

It is better to suffer with no A/C than buy a new generator winding.

Choices: nice to see someone here that knows his breakers. fyi, i am working on a breaker monitor design. And i calculated the break Amps vs number of opens via equations. Been working with 4kA rated, 238kV line and some 40kA interrupt. And u are correct. Even with this monster, its rated at only one opening at max. Vs a mechanical rating of 5000 before overhaul.

I tried to make it as simple as possible. I taught this stuff to gear builders and OEMs.

But you are correct, the design criteria is pretty much universal. From a safety point it has to be.

I have learned a lot here, trying to give a little back.

It is hard to get 4000 amps at 238kv!

We should post some substation switching arcing videos on here. I may try.

Preparing breakfast on a 30Amp boat with electric stove and a microwave is always interesting.
Using 2 burners.....
A. open the breaker for the hot water heater.
B. put the microwave on the inverter.
I have 3 breakers that like to trip if I dont perform A and B...... the one just inside the boat, the house power at the breaker panel or the breaker for the outlets in the galley.
I dont get excited, I just consider it normal LOL
I just wish the same breaker would trip but noooooo, I have to search.....
Makes life interesting.

Sorry for hijacking the thread.
But for electrical guys this is like porn.


Hope the link works.

OldDan1943 said:

Preparing breakfast on a 30Amp boat with electric stove and a microwave is always interesting.
Using 2 burners.....
A. open the breaker for the hot water heater.
B. put the microwave on the inverter.
I have 3 breakers that like to trip if I dont perform A and B...... the one just inside the boat, the house power at the breaker panel or the breaker for the outlets in the galley.
I dont get excited, I just consider it normal LOL
I just wish the same breaker would trip but noooooo, I have to search.....
Makes life interesting.

Click to expand...

I did a fuse coordination for a job at a nuke site. The idea being to make sure the fuse blows that is closest to the fault. But, it sounds like u may have a couple breakers with the same rating upstream. That makes the puzzle more interesting, maybe even unsolvable.

Choices said:

Sorry for hijacking the thread.
But for electrical guys this is like porn.

Hope the link works.

Click to expand...

My buddy had his laptop die from this. And that was maybe 40 yards away. [emoji51]

And, I cross my fingers that my rental car starts when parked under 500kV air lines.

Greetings,
Mr. OD. Sounds like you're going to have to do a conversion and get Mr. dd to set it up for you.





Edit: Mr. dd. Used to work with a group doing EMP research. That's all I'm allowed to tell you.

diver dave said:

I did a fuse coordination for a job at a nuke site. The idea being to make sure the fuse blows that is closest to the fault. But, it sounds like u may have a couple breakers with the same rating upstream. That makes the puzzle more interesting, maybe even unsolvable.

Click to expand...

I know I overload the breakers and they trip. That is why they are there. It sure would be nice to have and amp meter in the galley.

The breakers closest to the shore power plugs, onboard, were changed. All the shore power breakers on the board were changed. I changed them because they were 10 years old and figured the springs might be getting tired.

This boat would be two steps closer to perfection if it were 50amp boat and had a bigger hanging closet. LOL Given a choice, i'd opt for the bigger closet. SMILE

diver dave said:

My buddy had his laptop die from this. And that was maybe 40 yards away. [emoji51]

And, I cross my fingers that my rental car starts when parked under 500kV air lines.

Click to expand...

I too was nuked trained... main propulsion.
I think I had a core melt down because I am now dumber than a rock and I dont care. No longer am I worried about travel restrictions. On a good day, I remember to put clothes on, tie my shoes, put my teeth in and zip up my fly. Anything beyond that, not necessary. LOL

RT Firefly said:

Greetings,
Mr. OD. Sounds like you're going to have to do a conversion and get Mr. dd to set it up for you.

Edit: Mr. dd. Used to work with a group doing EMP research. That's all I'm allowed to tell you.

Click to expand...

Thats very cool. I saw me first emp test fixture about a year ago. Small one. I am blessed by the fact i have not had to sign any security paperwork [emoji41]

diver dave said:

Thats very cool. I saw me first emp test fixture about a year ago. Small one. I am blessed by the fact i have not had to sign any security paperwork [emoji41]

Click to expand...

DD, we both know, if you have ever signed the paperwork for a security clearance, your security clearance may expire but, the paperwork lives on forever. At the drop of a hat they can bring your clearance up to date just before they throw you in prison. SMIRK

caltexflanc said:

Grab the ends of those cables every day if you can. If you feel warmth, investigate.

Click to expand...

+1000 I try to remember to touch the cable every day just to monitor. Had an external plug go bad but I happened to be onboard when it started to overheat. It left a lsdting impression on my little brain.

Wish I had a temp alarm on it.

https://assets.omega.com/resources/temperature-labels-tl-ti.png

Lots of varieties avail.