Breaker Switches vs Fuses

[rwidman]

Originally Posted by TooCoys

Post #8


I want to rewire the boat completely so that I know where everything is, and how its wired.

Unless there are issues, I would advise against that. It's a lot of work, especially for a beginner and in the end, you have the same boat but you've put a lot of time and money into a job that didn't need to be done.

If you can't figure out where everything is and how it's wired, it would be less costly to hire a qualified marine electrician to show you this. Far less costly.

[transmitterdan]

Originally Posted by exMaggieDrum

The discussion of interrupt ratings is certainly useful but will certainly just be right over the tops of the average cruiser's head. I have worked on hundreds and hundreds of boat electrical systems and I can't recall any major problems (fires, etc.) from using the run of the mill (good) breakers, such as the Class A's from Blue Sea. I am just completing my new BS DC panel and finished my AC panel previously and I have no concerns about them.

DIN mounts are great but the parts and breakers are not easily found by the average boater in the US nor is the expertise to design and install them. They are far more common in European boats. I have mostly seen them on the very large high-end boats who had commissioned electrician engineers on the specification and design team.

Just my observations in the field.

Anecdotal information can lead to nasty surprises. Current interrupting ratings of D.C. protection devices are not arbitrary. If one uses the wrong type of fuse in large battery circuits they may not open as desired. They can flame and continue to burn until the batteries are drained. This has caused fires in the past.

It is precisely because of complicated design issues like fuse ratings that untrained people should not be rewiring their boats. Invariably they do it wrong. Then complain about not being able to get insurance because they fail an insurance survey. It's a penny wise pound foolish approach.

[Cadence]

Originally Posted by rwidman

I wouldn't use one for the cabin lights or even navigation lights, but a breaker switch is fine for things like a refrigerator or the automatic water pump.

The OP never said why he wanted to know the difference, but as a practical matter, the boat manufacturer usually installs the appropriate device.

Ron, I think it was for rewiring a 67 Chris Craft. In another post it sounded like it had AC fuses of the type found in 40s and 50s houses the screw in type.
I guess I learned something about duty cycles of breakers used as switches or at least claimed probably OK.

[lesterbutch]

I'm a former marina owner and worked at several large commercial boat yards. The number of fires, short circuited equipment, damaged engines, etc. that I saw was frightening. Almost all of it caused by amateurs! Boats are not like houses, they move and continually work, fertile ground for short circuits! Do yourself a favor, let a marine certified professional do it! It's worth the money.

[Cadence]

Originally Posted by lesterbutch

I'm a former marina owner and worked at several large commercial boat yards. The number of fires, short circuited equipment, damaged engines, etc. that I saw was frightening. Almost all of it caused by amateurs! Boats are not like houses, they move and continually work, fertile ground for short circuits! Do yourself a favor, let a marine certified professional do it! It's worth the money.

Who certifies them?

[transmitterdan]

Originally Posted by Cadence

Who certifies them?

See for example:

http://abycinc.org/?page=CTD

[Cadence]

Originally Posted by transmitterdan

See for example:

Certified Technician Directory - American Boat and Yacht Council

Thanks. I didn't get much from it as proving proficiency?

[Lake-Effect]

Originally Posted by TooCoys

Post #8

I want to rewire the boat completely so that I know where everything is, and how its wired.

I'm semi-pro - I have ABYC certification and electrical experience both in marine and elsewhere, but I'm not that active in marine these days.

This year I worked with one owner who wanted to get a handle on the electrical system of the new to him 30 ft European racer/cruiser.

In about 2 hours I was able to go over the system with him, explain stuff he was unsure of, and help trace things he couldn't identify. We also identified 4 or 5 small faults (including charger settings, loose connections, defective breaker, poor contact in one inline fuse)

So before you go whole hog with a rewire, book a pro for a couple of hours to review your boat's electrics and answer your questions. There may be nothing seriously wrong with your boat.

[Lake-Effect]

Originally Posted by Cadence

Thanks. I didn't get much from it as proving proficiency?

There isn't as yet a dedicated "marine electrician" diploma/degree anywhere that I'm aware of. Most college "marine tech" courses teach a bunch of different things, including electrical. Some marine electrics manufacturers probably offer training too, though I'm not aware of any that have a widely-recognized certification, equivalent to the Mercury marine training for engine guys. So most marine electrical techs will have electrical experience/training from another field - eg house electrician, automotive, electronic tech, etc, combined with on the job experience with the marine specifics.

The ABYC certification testing is intended to test on a combination of standards knowledge, electrical theory, and practical knowledge. One needs to do better than 80% to pass.

So, by providing a set of industry accepted standards, and these certification programs, the goal is to provide a voluntary standard where one doesn't currently exist, and I think ABYC is currently the de facto standard for many manufacturers, surveyors and insurers.

Does ABYC certification guarantee proficiency? Not necessarily, but in a field where anyone can claim to be a marine tech, it's evidence of at least some knowledge. I guess this will be borne out by people's experience - if they are more satisfied with the work from an ABYC certified provider... that reinforces the "brand".

[john61ct]

I thought there was a practical experience "apprenticeship" requirement as well?

[Cadence]

Originally Posted by Lake-Effect

There isn't as yet a dedicated "marine electrician" diploma/degree anywhere that I'm aware of. Most college "marine tech" courses teach a bunch of different things, including electrical. Some marine electrics manufacturers probably offer training too, though I'm not aware of any that have a widely-recognized certification, equivalent to the Mercury marine training for engine guys. So most marine electrical techs will have electrical experience/training from another field - eg house electrician, automotive, electronic tech, etc, combined with on the job experience with the marine specifics.

The ABYC certification testing is intended to test on a combination of standards knowledge, electrical theory, and practical knowledge. One needs to do better than 80% to pass.

So, by providing a set of industry accepted standards, and these certification programs, the goal is to provide a voluntary standard where one doesn't currently exist, and I think ABYC is currently the de facto standard for many manufacturers, surveyors and insurers.

Does ABYC certification guarantee proficiency? Not necessarily, but in a field where anyone can claim to be a marine tech, it's evidence of at least some knowledge. I guess this will be borne out by people's experience - if they are more satisfied with the work from an ABYC certified provider... that reinforces the "brand".

Thanks, at least it means the person has made an effort.

[Lake-Effect]

Originally Posted by john61ct

I thought there was a practical experience "apprenticeship" requirement as well?

Not for ABYC certification, but the certification test does draw a fair amount on practical knowledge, so it's hard for most to pass it without having had some experience.

The costs and the high pass mark required help somewhat to weed out the inexperiencied or uncommitted.

[mitiempo]

Originally Posted by exMaggieDrum

The discussion of interrupt ratings is certainly useful but will certainly just be right over the tops of the average cruiser's head. I have worked on hundreds and hundreds of boat electrical systems and I can't recall any major problems (fires, etc.) from using the run of the mill (good) breakers, such as the Class A's from Blue Sea. I am just completing my new BS DC panel and finished my AC panel previously and I have no concerns about them.

I don't think there is any real problem with A series breakers in either an AC or a DC panel. Ampere interrupt capacity does become a problem with loads like windlasses, thrusters, and starting circuits. These are the locations where I use high AIC fuses like ANL, MRBF, or Class T.

[mitiempo]

Originally Posted by Cadence

Ron, the problem with using a breaker as a switch is they have a duty cycle. It may not be significant if switching isn't a regular thing.

The 10,000 cycles that an A series Blue Seas breaker is rated for translates to almost 14 years @ twice per day. I don't think is is much of an issue really.

[Colin A]

Originally Posted by Lake-Effect

Not for ABYC certification, but the certification test does draw a fair amount on practical knowledge, so it's hard for most to pass it without having had some experience.

The costs and the high pass mark required help somewhat to weed out the inexperiencied or uncommitted.

Actually they changed that now. I used to have my electrical Certification but let it lapse as I wasn't using it. If I redid it I would now get a Advisory certification as I work for a equipment manufacturer but don't work in the field on boats.

New Certification Requirements - American Boat and Yacht Council