Fuses v. Breakers

[reeljob]

Any particular high points to either? I'm replacing the switch panel on my 'glass boat and I got a Blue Sea Weather Deck blade fuse panel. However, I was planing to use the same thing but in the breaker version on my Simmons when the time comes. The breaker switch panels are more expensive initially, but you don't have to keep spare fuses. I think i like being able to see immediately what rating the fuses are and being able to easily replace them. Any thoughts?

[Figment]

Though I generally favor breakers, the fuse panel gives great flexibility to adapt as onboard systems change, a simple matter of swapping out the $0.28 fuse instead of the $28 breaker.

[Gary E]

I never had breakers, so I dunno about them,
but I did have FUSEs and I do know I NEVER blowed or had to replace one...

[Donn]

My cruiser has a fuse panel, and I just blew the first fuse in 8 years, in the AC circuit, when a plastic bag got hung on my ice-eater.

[Joe ( Cold Spring on Hudson )]

Wow! An on-topic response! What a novelty.

[Gary E]

If your system is complicated.... use Breakers

http://newimages.yachtworld.com/1/6/1/2/8/1612815_22.jpg?1172093643389

[Figment]

Hey, at least they kept the weight on centerline!
(imagine the amount of wiring behind that thing!)

Joe, play nice above the bilge!

[paladin]

I prefer breakers.....I have worked on too many electrical problems on boats where the fuse never blew and started fires...because the fuse contacts etc corroded and bridged the glass/ceramic part of the fuse. If you use the fuses, mount them inside a watertight box, be sure to open the box at least once a year and check for corrosion, put a bag of dessicant in the box and reclose it. Marine/aircraft breakers are sealed, and once the wiring is installed and tested, then coat the terminals with an electrical non corrosive sealer...

[brad9798]

I have fuses in the boat ... prefer them greatly ... fuses do not/cannot hide problems like breakers can sometimes do.

I actually prefer fuses in houses too ... but most of the world looks for the upgraded 150/200 amp service box ... although 7/10 times the wiring is still original.

Perception is reality.

The only fault with the old knob and tube wiring in homes prior to WWII was the insulation ... the grounding could easily be corrected.

They were solid copper wires ... not braided (cheaper) strands ...

But again, perception is reality ... in selling houses over the years, a fuse box with totally updated wiring will NOT sell as quickly as a breaker box with crappy old wiring ... inspectors/buyers/REagents LOVE breakers ... not sure why.

[Donn]

Curb appeal.

[epoxyboy]

Nice thing with (some) breakers is that you can isolate the circuit by pulling the breaker knob. Sure you can pull a fuse, but they ALWAYS mysteriously disappear when you go to refit them.

Pete

[The Bigfella]

Sometime soon, I'll be running the wires to the three Blue Seas breaker panels on Grantala. It seems a bit of overkill to have three panels and all that is hooked up to it is my radio. I totally concur with Chuck's comments - virtually every fuse I've ever seen on a boat has been corroded.

[Gary E]

- virtually every fuse I've ever seen on a boat has been corroded.

That generally means
a... I have not seen all that many boats
and
b... those I did see were wired by incompetent electricians or someone pretending to be an electrician

Fuses have been used for a much longer time than circuit breakers

[ssor]

The original fuse panel in my boat was mounted on the portside quarter berth well below the water line. Such a wonderfully dry, well ventilated space. The wire was always the first thing to turn green in the spring.

[Andrew Craig-Bennett]

All breakers on my boat; never had a problem with them.

[Canoeyawl]

I’m not clear on what type of “circuit breakers” you are considering, but there are breakers that will fit in a standard 12V fuse panel, perhaps the best of both worlds. This type of breaker can have the added advantage of automatically resetting; to let the lights come back on for a moment…
All electrical connections in a boat have potential corrosion issues.

[Dan McCosh]

We have all breakers, and never actually considered fuses, other than a couple of in-line fuse holders. The breaker panels is sometimes handy as a switch box to positively cut off a circuit. For some installations, such as refigeration, this is a handy feature. At least one panel is in use as a switch box for running lights, etc.

[Tylerdurden]

I am real big on breakers for anything I wire, I don't always use sealed breakers as they are hard to come by and not cheap. I have built panels on boats since 85 and to tell the truth unless its a really wet environment the reliability of a good quality electronics grade breaker works out in a cost factor basis. I end up changing the sealed at close to the same rate. I have been using the Tyco brand in toggle types for most applications W-6 and W-31 series mostly.
They have been working quite nicely since I have been using them and the prices are not to bad.
Fuses are a pain in the arse when you really need to change out one in a hurry and if you have an intermittent but still need that equipment you better have a few dozen fuses of each amperage on hand.
You might wipe out that breaker but you can still get home.

[RodB]

I have the Weather Deck panels and I contacted the tech guys at Blue Sea when I purchased them asking this same question. The guy I talked to said the fuse type offer more accurate protection because fuses were made to fail at very close to their specified amperage, where breakers did not perform to the same level of accuracy. He said the fuses would protect your appliances better and that almost any amperage was available and that breakers did not offer the selection of sizes. Note: we were talking about protecting appliances such as GPS, lights, VHF radio, etc that drew low amps. He also said that if you were not protecting electronics with very low amp draw, that breakers were a great way to go. Naturally, the circuit breakers cost more too. I selected these switch panels because of the ease of access to changing fuses (and breakers).

http://www.imagestation.com/picture/sraid224/p6eb8e94675b8049d1f305889a70cc0bc/ea8f80e5.jpg

Note: I would forgo the Weather Deck switch panels in the future because although waterproof on the top surface the backside even if protected will corrode as it is an open circuit board with solder and a few terminals. In a salt water enviornment this will corrode unless very well maintained.

I usually rinse with fresh water and after drying, spray with a very good anti corrosion electrical spray. So far so good but I only go in salt water now and then, and always rinse and clean up everything after fishing.

If starting over, I would use the Cole Hershee individual waterproof switches that can be fitted in groups of three. These switches have only two terminal posts exposed to the outside and have been recommended as much better for withstanding the salt water environment. They come in single and double throw in every variation. All you would have to do is coat the snap on connections with liquid electrical tape.

Naturally, with this system you would have to have a separate fuse or breaker panel, and that element of the system needs to be executed well to insure corrosion protection.

RB

[paladin]

Off hand I would say that the person that gave you that information was not very knowledgable.....I can positively guarantee you that a solid state circuit will blow before the slo-blo fuse.....A circuit breaker is generally slower to react than a fuse...it is true...but.....in a spike situation the solid state stuff goes first....and if it blows the circuit breaker then something has already failed inside the box. Cheap electronics are all basics....a vhf radio costs 25 bucks to build and market, that's why they retail for 99 bucks or so.....a properly constructed unit will have a bridge diode circuit inside that prohibits you from accidentally reversing the power leads, and zener diodes across the input to prevent overvoltage spikes above 18 volts, and other features....There's a reason most aircraft electronics are placarded to read, "turn off all electronics before starting engine"!...the initial spikes from the overvoltage from a generator/alternator is there for milliseconds before the regulator reacts.......

[RodB]

Paladin,

Naturally the Blue Sea tech guy was explaining how to utilize their switch panel.

So, are you saying the appliance's own protection will go before the auto type fuses in these switch panels? Is it not a good idea to place a low amp fuse in line to protect electronics. How about the bilge pump circuits running lights, etc? I guess all electronics (VHF, GPS, AM/FM/) could be on one switch with an appropriate fuse. I realize the fuses are to protect your wiring system, not really save the appliance if it can be damaged.

I wired my boat with these switch panels because they offered an easy way to protect my circuits with easy access to the fuses from the top panel of the switch. You said the breakers reacted slower than the fuses... then why not use fuses....? please elaborate.

RodB

[Peter Malcolm Jardine]

There are different kinds of fuses, and there is nothing wrong with a well constructed fuse panel... The reason the insurance business likes breakers is that you can't change the value of a breaker to suit something stupid that has been done on that circuit. I have fuses, and there is not problem with them... but I will probably go to breakers for some of the convenience reasons outlined above.

[paladin]

Solid state electronics use (of course) transistorized circuitry. By it's very nature it is normally an electrically fragile device...when it comes to fuses or circuit breaker, one is not necessarily better than the other. A slo-blow fuse is designed to take time dependent surges of power....voltage is not worse than current, except for the fact than an increase in voltage will cause an increase in current. It is the combined energy that heats the metallic strip and breaks the fuse...
A circuit breaker is designed for a specific voltage range and current application, it will react in much the same way, but will trip just a little slower under the same circumstances.
A device such as lighting circuits, bilge pumps, and other such devices that are not based on "transistor" applications will not normally be affected by sudden spikes, overvoltages, or power surges....eventually they may fail, but the reasons are generally other causes.
This is also why I have a problem with some products currently on the market. An example is LED lighting which has been discussed on this forum. A person ties three or four lED's together with a resistor and has a solid state light product. With voltage spikes etc present with incandescenr bulbs it is not a problem...but the LED's are solid state devices and require some form of control/isolation to be used properly. Also LED's tied together generate heat, which causes the lights to degrade.
Another problem that was mentioned...keeping a lot of fuses....if one blows, you may need several to help you isolate the problem, whereas you can disconnect the equipment and keep flipping the breaker to isolate the fault.....I do not wish to imply that this is proper "troubleshooting".....when you are somewhere you don't wanna be, all bets are off.

[willmarsh3]

The breakers being electromechanical would react slower than millisecond voltage spikes such as occurring during starting the engine. There's something called Zapstop that I think would address that issue. Would that make sense? Or does it only protect the voltage regulator on the alternator? I don't have a Zapstop yet but I'm thinking of getting one.

[epoxyboy]

Solid state electronics use (of course) transistorized circuitry. By it's very nature it is normally an electrically fragile device...when it comes to fuses or circuit breaker, one is not necessarily better than the other. A slo-blow fuse is designed to take time dependent surges of power....voltage is not worse than current, except for the fact than an increase in voltage will cause an increase in current. It is the combined energy that heats the metallic strip and breaks the fuse...


A "solid state fuse" is is basically nothing more than a current dependant resistor with a very non linear resistance to current curve - they are extremely robust, and transistors dont feature. A solid state circuit breaker on the other hand.......
Also bear in mind that fuses/breakers are not there to "protect" the likes of marine electronics - they can't and won't in most circumstances. What they will do is prevent damage to wiring in the event of a short circuit - and unfused circuit with a direct connection to the battery will get red hot and can set fire to your lovely boat. About the only other things that will be "protected" will be the batteries and alternator.

Pete

[Tylerdurden]

The breakers being electromechanical would react slower than millisecond voltage spikes such as occurring during starting the engine. There's something called Zapstop that I think would address that issue. Would that make sense? Or does it only protect the voltage regulator on the alternator? I don't have a Zapstop yet but I'm thinking of getting one.

Breakers can be had in different delay curves, Trick is to not just look at "marine" breakers. Its a scam and limits your options.
Paladin is right on on this.
I have Pdfs of some available types and the options are almost limitless.
As far as starting goes I have never had a problem with transients.
If properly wired the threat is minimal at best and Like Paladin say's Just like in aircraft there is no need to have systems powered up during starting. Thats why I like remote breakers. I can control the power panel from the helm station and keep the breakers where they belong.
A good habit to get into is to have a At dock and underway plan for your panel. No need to have everything live all the time.

[paladin]

Will...I believe your "Zapstop" product is nothing more than a zener diode.....you place it across the voltage terminals and if the voltage exceeds a predetermined level it will short to ground momentarily.....and I dunno the price of your "Zapstop"....but you can buy a 14.1 volt zener diode for less than a buck from Digi-key"....of course it dunno got "Marine" stamped on it...:D

[willmarsh3]

This is a good, informative thread. I'll add one more thing. I like fuses because their condition is quite self evident - at least for the glass tube with metal end cap type that I have. Along with proper quality wiring and operational plans comes regular inspection and maintenance - which should catch the type of bridging corrosion that Chuck mentions. Breakers are generally sealed units, more complex, and their condition after being installed in a boat for years is harder to evaluate, IMHO.

[willmarsh3]

Will...I believe your "Zapstop" product is nothing more than a zener diode.....you place it across the voltage terminals and if the voltage exceeds a predetermined level it will short to ground momentarily.....and I dunno the price of your "Zapstop"....but you can buy a 14.1 volt zener diode for less than a buck from Digi-key"....of course it dunno got "Marine" stamped on it...:D

Thanks, Chuck. But shouldn't the zener diode be a bit higher than 14.1 volts? Say 16v? My alternator puts out up to about 14.4v to charge the batteries. And that voltage is what the wiring assumes during charging.

[paladin]

strictly an example.....most electronics specify not to exceed 16 volts...and a 14.1 volt zener will break about 15-16 volts....it's a nominal value.....the idea is to protect the electronics, not the breaker...the breaker can be reset after the impulse is gone....
On my power supply designs I specify a minimum of 10 volts input, to a maximum of 40 volts, the inputs are protected for polarity reversal by a diode bridge (it doesn't care which way you connect it) and the supplies are current limited with a nominal 12.5 volts output.
Under those circumstances the electronics will continue to function correctly even with low battery power or overvoltages without system damage....My company in Honduras has sold over 2500 of these things to both givment and commercial interests, and only one has come back with a component failure, and that was a capacitor....The unit is the size of a pack of 100mm cigarettes and produces 12.5 volts at 15 amps continuously at about 96% efficiency....modern magnetics and spacecraft qualified parts help....

[George.]

So far, by glancing at the "Location" of posters, the conclusion seems to be: breakers in salt water, fuses in fresh. :D

[willmarsh3]

strictly an example.....most electronics specify not to exceed 16 volts...and a 14.1 volt zener will break about 15-16 volts....it's a nominal value.....the idea is to protect the electronics, not the breaker...the breaker can be reset after the impulse is gone....
On my power supply designs I specify a minimum of 10 volts input, to a maximum of 40 volts, the inputs are protected for polarity reversal by a diode bridge (it doesn't care which way you connect it) and the supplies are current limited with a nominal 12.5 volts output.
Under those circumstances the electronics will continue to function correctly even with low battery power or overvoltages without system damage....My company in Honduras has sold over 2500 of these things to both givment and commercial interests, and only one has come back with a component failure, and that was a capacitor....The unit is the size of a pack of 100mm cigarettes and produces 12.5 volts at 15 amps continuously at about 96% efficiency....modern magnetics and spacecraft qualified parts help....
Thanks for the clarification. Can you please pm me the model of the power supply or the name of the company? I'm wondering if it is something that would be appropriate for my boat.

[paladin]

Naw, Will....it's a MIL spec power system for jammers and tactical communications...and the price would scare ya....:D
I decided a gazillion years ago to design weird things that I could make a few of and sell for lotsa dollars.....it's a lot more fun than selling a gazillion of something for a buck ninety eight...keeps the company small and manageable so I can do it by remote control.

If you have a specific need for stable power....there are companies like "Power One" that make commercially available supplies with various input voltage ranges and can supply a regulated output....
Google "POWER ONE" or check the digi-key catalog...digi-key as a warehouse type supplier would probably be cheaper than going direct.
If you have a specific need, send the specs and I'll look for something for you..

[willmarsh3]

You're right. I don't need something like that for cruising around the lakes and rivers and such. But that looks like an excellent business strategy.

[carioca1232001]

At my helm station on my motor-cruiser, all the Nav lights, flood lights, helm station lights/lighting, engine-room blowers etc are connected via Blue Seas splash/spray-proof (not water-proof !) fused-switch panels.

A total of 3 such panels, one being a 6-switch and the other two, 3-switch. On the latter ones, a couple of the front access twist-out fuse-holder caps got sore and instead of replacing the whole panel, I was lucky to locate a retrofit replacement fuse-holder (Blue Seas) from a Web-store dealer out in N Carolina (can´t remember their name) . No other problems with the fused-switch panels, touch wood.

In the main cabin, some more Blue Seas gear, viz., a 10-breaker DC panel, a 3-breaker AC Panel, complete with a sliding shore-power to genset/inverter selector. This 10-breaker DC Panel addresses the needs of the main cabin, galley, loo and V-berth area. No problem whatsoever, touch wood again.

Now as for protection from spikes, I have used suitably rated MOVs (metal-oxide varistors). They take more of a beating than Zener diodes and despite a much higher capacitance, there are no high-frequency devices in their path whose bandwidth they may deteriorate. Do MOVs cost more than Zeners ? Don´t know, was a long time ago.

As for 12- Volt DC (nominal)supplies, on boatdesign net there was a chap suggesting using cheap and robust Computer power supplies, wired up in paralell.

Can anyone comment ?

[carioca1232001]

Some of the circuits connected to the 10-Breaker DC panel are set up as follows:

Take the main cabin lighting for instance, 5 x 15 Watt incandescent lamps. A n-fuse holder is used, fed on one side from the hot-side of one of 10 the circuit breakers on the DC panel. The hot-path to each lamp is via an individual fuse. All the return wires from the lamps go to a common bus-bar and a heavier gauge wire connects the latter to the negative bus-bar on the 10-breaker DC Panel.

So the breaker performs a rear-guard (retaguarda ?) function, 'looking-over the shoulder' as it were, of the individual fused circuits.

Will appreciate comments, if any.

[paladin]

If you are referring to using parallelled UPS supplies....it's a bit expensive to do it that way, and the supplies were designed for very short duration work...definitely not continuous duty in any stretch of the imagination..

[carioca1232001]

The chap on boatdesign net who proposed the idea of using 110 V AC 50/60 HZ to 12 V DC (nominal) computer power supplies - and I think he may have actually put it into practice, can´t remember now -has the following philosophy :

"When you are docked and connected up to shore power, simply undo the connection between your house battery and the house bus-bar and have the latter fed with PC grade power supplies (in paralell if required).
While you are so connected, have a battery charger to replenish your house battery."

So in an attempt to suggest a solution to willmarsh3´s power supply needs, of which I know not enough about, I brought up the subject of PC power supplies for boaters while at dock.

No doubt, your state-of -the art design is definitely an overkill for willmarsh3´s application (boating), including pocket-wise !