For Safety's Sake Use Fuses

[Maine Sail]

Did a trouble shooting consult yesterday and found this. Note how the wire had been connected to the batt switch post by simply wrapping it and tightening the nut down.

There was soooo much wrong with the PO's DIY wiring on this boat it would have been difficult to know where to begin. I really felt bad for the guy but referred him to a good marine electrician as I do not have the time to tackle his job and my own lightning strike right now.

As a point of reference the MANUAL mode / side of a bilge pump switch should ALWAYS be a momentary type switch not an ON or OFF. You should have to hold it to keep it in manual mode not be able to turn it on and walk away. Catalina made a dumb mistake on this switch and the whole panel on this boat for that matter with multiple circuits sharing a single breaker.

The guys daughter accidentally turned the bilge pump switch to MANUAL as opposed to AUTOMATIC and the pump literally melted down and created a dead short. I wish I had my camera with me!

The dead short melted the approx 16GA wire between the battery switch post and the panel switch mounted bilge pump switch. It melted into the jacket of multiple other wires including a ground wire before the plastic bilge pump switch melted and broke the circuit. Switches should NOT be depended upon for circuit protection. I gave the guy an in-line fuse holder that I had on-board at N/C..

FUSE your stuff !!!!!!!!!!!!!!!


This guy came about a gnat hair away from a really bad boat fire!!

Off to go sailing!!!!!!

 

[Paul F]

Re: Please Use Fuses !!!!!

Maine Sail, I have a friend who is putting two large alternators on his Valiant. He asked what type of fusing should be used between the alternators and the batteries. I was at a loss to tell him what if anything was needed. What would you recommend?

 

[Stu Jackson]

Re: Please Use Fuses !!!!!

Mega fuses or ANLs would work just fine. If wired directly to a house bank, a switch wouldn't hurt either, 'cuz if the wires at the back of the alternator get loose in any way, it'd be a lot easier to turn the circuit off with a switch or a redundant circuit breaker than it would be to to try to find the right side socket to disconnect the fuse.

 

[Ross]

Re: Please Use Fuses !!!!!

Won't breaking the output circuit from alternator to battery distroy the diodes?

 

[Hermit Scott]

Re: Please Use Fuses !!!!!

The only thing I have unfused is a 5w solar panel clipped directly to the posts. Is there potential for disaster there?

 

[Stu Jackson]

Won't breaking the output circuit from alternator to battery destroy the diodes?

Ross, yes it would if you turned it off when the alternator is putting out. However, if you reread my post, it says: when the wires got loose at the back of the alternator. By then, ya got a BIG problem anyway! I learned this because it happened to a friend.

 

[Stu Jackson]

The only thing I have unfused is a 5w solar panel clipped directly to the posts. Is there potential for disaster there?

Scott, the panel manufacturers all recommend it. That was kinda the whole idea of Maine Sail's original post and suggestions. Please fuse it for your own safety.

 

[druid]

The only thing I have unfused is a 5w solar panel clipped directly to the posts. Is there potential for disaster there?

Actually.. yes. I had my solar panel TEMPORARILY wired up with clips, and the clips shorted out. Say goodbye to two jumpers and took several hrs to get the acrid odour out of the cabin.

druid

 

[Maine Sail]

Actually.. yes. I had my solar panel TEMPORARILY wired up with clips, and the clips shorted out. Say goodbye to two jumpers and took several hrs to get the acrid odour out of the cabin.

druid

Druid,

I make up my own test jumpers with alligator clips only they all have an in-line fuse holder because sh&t happens... If I had a dollar for every fuse I blew on a test lead, well....... Of course I would advise others to always turn stuff off before wiring. To bad I don't always listen to myself...:cussing:

 

[Ross]

Re: Please Use Fuses !!!!!

My concern was with the fuse in the output circuit per PaulF. How can the alternator circuit be protected while also protecting the alternator(s)? This presumes no accidental short circuit caused by misplaced hardware just normal operation before an over current happens.

 

[Maine Sail]

My concern was with the fuse in the output circuit per PaulF. How can the alternator circuit be protected while also protecting the alternator(s)? This presumes no accidental short circuit caused by misplaced hardware just normal operation before an over current happens.

Ross,

If you're wiring to ABYC E-11, and the alt is wired directly to a bank of batteries as many do, then you need a fuse to protect the WIRE within 7" of the positive battery post. This fuse is not intended to protect the alternator but rather the wire in the event of a direct short. If this fuse blows you possibly just saved your alt anyway.

Any wire connected directly to the battery is supposed to be fused with the exception of a dedicated cranking battery. I still fuse start/reserve banks on engines under 100HP. Remember E-11 also covers boats with 4000 HP and there is no fuse that will not blow firing up one of those babies, hence the exception for cranking batteries.

Stu only advises an on/off switch so you can work on the alt without having to remove a fuse. This switch would ideally be well hidden and not used often except when you want to work on the alt. You would obviously NOT turn this switch with the motor running..

This is how I met E-11 on my own boat: From L to R Alternator Fuse, House Bank Fuse, Batt Charger Fuse (these three are bussed together on the inlet side), Inverter Fuse, Reserve Battery Fuse:

P.S. The 16ga wire likely would have melted before a 250 amp ANL fuse so you still need to fuse all branch circuits AND the batts.

 

[Stu Jackson]

Stu only advises an on/off switch so you can work on the alt without having to remove a fuse. This switch would ideally be well hidden and not used often except when you want to work on the alt. You would obviously NOT turn this switch with the motor running..

Agreed, but the purpose is twofold: one as MS says, which he & I picked up discussing this subject on the YBW English website, where they charge their reserve banks first, BTW. Weird.

Anyway, the basis for this suggestion comes from a friend whose alternator wiring disintegrated and he was having a raft of issues at the time, sparks flying, while he figured out what size wrench to use to get the fuse (at the battery end) off his MEGA fuse holder to disconnect that wire.

Just makes sense. For safety

 

[Maine Sail]

Agreed, but the purpose is twofold: one as MS says, which he & I picked up discussing this subject on the YBW English website, where they charge their reserve banks first, BTW. Weird.

This is not necessarily their way and I suspect it is Charlie Sterling's way. His company, Sterling Power, builds an charge controller device called the Pro Split R that does that automatically so they have seemingly accepted that by default.

They have accepted Mr. Sterling's design as "the way it should be".. He's a good marketer that's for sure...

The device basically charges the start bank then disconnects it and charges the house bank. It's sort of an either / or charging device as opposed to a "combine" and charge both simultaneously. He always compares it to a battery Isolator which has been out of fashion in the US for a long while.

http://sterling-power-usa.com/ProSplit-RZeroVoltDropMarineBatteryIsolator-13.aspx

 

[JonnyQuest]

Re: Please Use Fuses !!!!!

Getting back to bildge pump failures...

My bildge pump inline fuse died on me this weekend (mechanical failure, not shorted out) and I didn't have a replacement. I went ahead and rewired the bildge directly for the time being, thinking I'd rather have the bildge burn out than the bildge not working at all (--recent stuffing box repacking, new cutlass bearing; c.b. was fast dripping, made adjustments and got it to a drip every 15-20 seconds now).

Another sailor suggested that he ascribes to keeping bildge pumps fuseless at all times because of the potential for fuses to take out your bildge--a critical piece of equipment on a boat. It seems to me that while his is a logical conclusion, I hadn't thought of a situation like this dead short situation. I'm reconsidering that suggestion now--proceeding with replacing my inline fuse and continue to check my bildge pump before/after each trip down to the dock or sail, and to keep 3-4 spare inline fuses onboard. Anything else regarding bildge pump safety? How about a backup pump? I do have a manual as well, but should I keep a replacement elec bildge pump onboard for emergency replacement? (I'm a weekend sailor only, and very near shore as of right now)

Thanks for the feedback!

JQ

 

[Paul F]

Re: Please Use Fuses !!!!!

O.K. I am following the reasons why to fuse all connections to the battery bank. Is it also a good idea to fuse between batteries in a battery bank?

 

[kenn]

Another sailor suggested that he ascribes to keeping bildge pumps fuseless at all times because of the potential for fuses to take out your bildge--a critical piece of equipment on a boat. It seems to me that while his is a logical conclusion, I hadn't thought of a situation like this dead short situation. I'm reconsidering that suggestion now--proceeding with replacing my inline fuse and continue to check my bildge pump before/after each trip down to the dock or sail, and to keep 3-4 spare inline fuses onboard. Anything else regarding bildge pump safety? How about a backup pump?

If you are frequently blowing the bilge-pump fuse, it may be too close in value to the actual pump demand. The fuse is for protection of wiring, which the batteries could melt in a heartbeat, so you might consider upsizing the fuse, as long as the fuse current rating can be carried safely by the pump wiring. You might also consider using a circuit breaker instead of a fuse for protecting the pump. Consult the ABYC specs for current handling for a given wire gauge and length.

 

[Maine Sail]

O.K. I am following the reasons why to fuse all connections to the battery bank. Is it also a good idea to fuse between batteries in a battery bank?

No real need to fuse the jumpers between batteries. Each battery consists of multiple 2 volt batteries inside and those cells are not individually fused. The only difference is the external case and the separate electrolyte. The fuse is to protect the wiring and 6" jumpers run little risk of a short when run series, parallel or series/parallel..

 

[CMM]

nice picture

Maine Sail, nice picture ! I guess I'm famous....or just lucky. I'd rather be lucky than famous any day.

I didn't catch the name of the electric supply company where I may be able to get a new panel switch. I know it is behind the EMS/Whole Foods stores but not the name of the company.

Thanks again

CMM

 

[Maine Sail]

Maine Sail, nice picture ! I guess I'm famous....or just lucky. I'd rather be lucky than famous any day.

I didn't catch the name of the electric supply company where I may be able to get a new panel switch. I know it is behind the EMS/Whole Foods stores but not the name of the company.

Thanks again

CMM

HR Distributors 101 Hanover Street. If Tip is to busy i may have some time next week. Just pm me.

 

[Roger Long]

my own lightning strike

Is there a post about this somewhere that I can't find?

Was it the big storm the night of July 20 when my son and I were in Greenland Cove, Muscongus Bay listening to tornado warnings for the whole area?

We were huddled up in the forepeak because I suddenly realized that the metal table supports and Dickenson cabin heater just inches from the mast support column will radiate a strike all over the main cabin. I haven't been able to think of any feasible way to ground the mast support column which ends on top of the encapsulated keel ballast that is probably filled with water in voids that will flash into steam explosions. The keel is so wide that there is no way to lead a strike to any kind of grounding plate with a generous enough radius to do any good. The only practical protection I've been able to come up with is prayer which I don't have much practice or experience with.

We heeled over for a minute like we were sailing. I looked out and the water surface looked like a road does when show is blowing over it in a blizzard. I threw my foul weather gear on ready to go out and run the engine to relieve the anchor but it held. I put the SPOT Beacon inside a cooking pot in case we were struck and needed to summon help.