For You DC Voltage Experts

[delmarrey]

I'm in the process of installing a new windlass (N. Euro made). The instructions says to splice the 135 amp breaker in the negative lead before going to the 3 wire motor.

On my old U.K. made windlass the breaker was spliced in the positive lead before going to the switching solenoid.

I've been working with DC voltage since 1966 and it seems the fuses have always been on the positive side of the wire looms. The negative side is the ground/earth side of the battery.

My question would be; why would anyone put a fuse/breaker on the negative side of a DC system?

Plus the red and black wires are not inline between the toggle and foot switch.

My intuition tells me to hook it up positive side to.

.

[David M]

I think your intuition is right.

Putting in a breaker after the load for DC makes no sense except if you want to use that as a switch to keep it from running.

From a safety perspective, you still need a breaker on the hot side to preserve the wire or to keep a fire from starting should there be a direct short or an overloaded circuit.

[Ex-Calif]

No expert but...

I wouldn't worry about the solenoid wires "crossing" inside the 3 wire bundle. Probably done to avoid "crossing them on the drawing. Seems obvious red/hot, grey/down, black/up.

I have no clue why they want the negative side fused. They also don't talk about where to fuse it. You also don't indicate where the components will be located.

If that big fat red wire chafes on a ground someday with the solenoid open, the fuse is isolated and nothing protects the hot side. I'd put the fuse close to the batteries on the hot side.

The no harm no foul solution is fuse both sides. Then you and the manufacturer are happy.

[DeepFrz]

Windlass and Bow Thruster Relay Contact Chatter - Resources - Blue Sea Systems

Blue Sea has a warning about contact chatter that can cause the relay contacts to weld shut. The fuse/cct. brkr should be as close as possible to the positive lug on the battery. I believe that ABYC calls for 7 inches max.

[delmarrey]

Thanks guys for reinforcing my intuition!

My set up has the breaker about 6" away from the battery positive terminal. The battery is mounted just behind the chain locker with charging leads running up to a combiner and the battery. And there is a fuse between the foot/hand switches and switching solenoid. Plus, I'm using 1/0 cable........._/)

And yes it is 7" per ABYC provisions of E- 11.12.1.1.1

[ishipaco]

I'll throw in my opinion on the side of those prior posts (and your intuition) that recommend installing the protective device, whether fuse or CB, in the positive lead to the windlass motor. It appears that the CB in your right-hand drawing IS actually installed in the hot lead. Hmmm...

I was also pleased to see that you located your battery forward and near to the windlass. That's often more trouble, but results in a much better, reliable system. Many people try to run a windlass using batteries that are located far aft. Even if one goes to the expense of installing long runs of huge, expensive wire (e.g., 1/0 or larger), voltage drops can still be a concern. Good job!

[Maggie-K]

When electricity was discovered, nobody knew how it works and
electrons were unknown. So the scientists just defined one of
the poles as "positive" and said that the current is flowing
from positive to negative. That still is the definition of an
electrical current's flow direction.
However, later scientists discovered that in most (but not all)
materials current is carried by negatively charged electrons,
which travel from negative to positive. The electron flow is
thus opposite to the current flow.
In some materials (e.g. electrolytic solutions) the current is
carried by positive ions, which travel in the current's direction.
And in semiconductors there can be currents of negative
or positive carriers, depending on the doping. Thus the confusion
over where a breaker should be located.

[delmarrey]

Maybe we should do a test. Take two lengths of cable exactly the same with a high amp breaker in the middle. Then throw the switch and see which end +/- gets the hottest.

BTW I received an email back from the manufacture and here's the reply.
"Hello

We recommends off course to follow etch counties regulations.

Best Regards
Roy Ilerod
Technical Manager"

Translated, I think, it says: We recommend, of course, to follow each counties regulations.

[Stillraining]

That depends....Some countries are off course...

Me thinks any one that use 240v on a boat for instance...

[MarkJ]

Originally Posted by Stillraining

That depends....Some countries are off course...

Me thinks any one that use 240v on a boat for instance...

There is only one country that uses 110 volts and thats a pack of pussies so scared they tried to only have non lethal voltage, instead of saying "Folks don't stick your fingers where they don't belong!"

The only countries that followed suit were/are camp followers of the first country. (and I don't mean gay camp, I mean camp camp before that word changed meaning. Its a gay ol day here too! )

The ONLY thing good about 110 volts are some of the appliances: a 110 shaver on 240v actuall shaves! a 110 fan on 240 cools! And a 110 toaster on 240V imoliates!

Go 240!!

[Blue Stocking]

Once saw a bowsprit ripped out of the foredeck by a big windlass. Turned out that the foot switch had filled with water, contacts welded shut, and with two sources of positive feed (schematic #1), fuse was bypassed. Bet he wished he had put a fuse on the single negative feed of the circuit.

[DeepFrz]

Electrical drawing #1 is a very dangerous drawing irrespective of the fuse location (+ or -). The small control wiring is only protected by the very large "motor" fuse. It would burn up long before the fuse blew. Could immoliate oneself (nasty toaster)...

[delmarrey]

Originally Posted by Blue Stocking

Once saw a bowsprit ripped out of the foredeck by a big windlass. Turned out that the foot switch had filled with water, contacts welded shut, and with two sources of positive feed (schematic #1), fuse was bypassed. Bet he wished he had put a fuse on the single negative feed of the circuit.

As well, he should have done the maintenance to prevent water intrusion, like a new switch when the boot starts to crack.

Boats are a lot like airplanes! A preflight inspection is a good thing. This is one of the problems of living aboard for some, oversight. A check list is a must just like in the Navy!

http://www.cruisersforum.com/forums/...ule-23330.html

[David M]

Originally Posted by MarkJ

There is only one country that uses 110 volts and thats a pack of pussies so scared they tried to only have non lethal voltage, instead of saying "Folks don't stick your fingers where they don't belong!"

The only countries that followed suit were/are camp followers of the first country. (and I don't mean gay camp, I mean camp camp before that word changed meaning. Its a gay ol day here too! )

The ONLY thing good about 110 volts are some of the appliances: a 110 shaver on 240v actuall shaves! a 110 fan on 240 cools! And a 110 toaster on 240V imoliates!

Go 240!!

Mark, I just want to make sure that people understand that plugging 120 volt alliances into 220 volts is more likely to destroy them possibly causing a fire, rather than making the appliance run faster. This of course does not mean dual voltage appliances that are designed for 220VAC-50Hz or 120VAC-60Hz.

Also, the higher the voltage, the more likely it is to kill. And yes, I know about current as well.

[Ike]

Normally the CB is installed at or close (as was said, ABYC and USCG say 7 inches) to protect the wiring, not the motor. It is the wiring that gets too hot and starts the fire. Howecver A few years back I did encounter a windlass that had two CBs. One, a normal fast blow CB, to protect the wiring, the other was a slow blow thermal breaker to protect the motor. It only blew if the motor exceed a certain temperature. In this case I believe the diagram is correct and it should be near the battery in the positive lead.

I haven't seen a positive ground boat in many many years.