Starter wiring with in line fuse?

[MarkSF]

Originally Posted by deblen

I believe you are correct Mark. Putting fuse at solenoid end does not protect the wire (from start switch to solenoid) at all. It should be at the start switch end,or,better still,the source for the whole start switch could be fused close to the bat. supply(usually the big pos term on solenoid that has the heavy cable to bat.)
Fuses should be close to the source. IMHO

Yes, I did place a fuse in the feed to the panel, as well as in the solenoid wire. I also have the MBRFs at the batteries.

[smac999]

The OP is talking about his ignition feed wire. not his starter wire. not sure how this topic got on starter fusing...

yes fuse the ignition feed wire as it leaves the starter post near the starter. a lot of boats don't. but I have seen this wire burn down a boat. since normally the starter wire isn't fused either. so you have a long unfused ~10awg wire from the back of the boat to the front and back to the back. a big fire waiting to happen if it shorts.

it's probably only a 10awg or smaller. this goes to the switch, feeds gauges, and back to the start solenoid so there is no need having another further upstream at the switch or solenoid.

but yes. also recommend fusing the starter line with ANL or MRBF normally in the 300a range

[skipmac]

Originally Posted by smac999

The OP is talking about his ignition feed wire. not his starter wire. not sure how this topic got on starter fusing...

yes fuse the ignition feed wire as it leaves the starter post near the starter. a lot of boats don't. but I have seen this wire burn down a boat. since normally the starter wire isn't fused either. so you have a long unfused ~10awg wire from the back of the boat to the front and back to the back. a big fire waiting to happen if it shorts.

it's probably only a 10awg or smaller. this goes to the switch, feeds gauges, and back to the start solenoid so there is no need having another further upstream at the switch or solenoid.

but yes. also recommend fusing the starter line with ANL or MRBF normally in the 300a range

Thread drift strikes again. The original question was answered so off onto a tangent we go.

[Stu Jackson]

OK, yes, thread drift, but let's get back to the original question.

Wire from the ignition switch to the starter solenoid. Many boats have a fuse that is in this wire. The fuse holder fails because it is cleverly hidden below the alternator or other hot and nasty places.

The point of my last link is that THIS fuse is useless, since it does NOTHING.

The real issue is to properly fuse the SUPPLY wire to the entire cockpit panel, not just a random wire from it.

Please, read the link that deblen agreed with.

Please.

That's all this was about until thread drift.

TD being a GOOD thing, sure, fuse "stuff" at the battery end, 'cusz that is the supply of voltage/power.

[smac999]

Originally Posted by skipmac

Thread drift strikes again. The original question was answered so off onto a tangent we go.

I see a lot of wrong answers talking about fusing the starter circuit which was not the question. (like your answer) and a couple answers taking about fusing this ignition circuit at the panel or start switch. which is no good as you would be missing half of the wire still unprotected between the starter pos post and start switch.

so I replied with a correct answer to his question.

[smac999]

Originally Posted by Stu Jackson

The real issue is to properly fuse the SUPPLY wire to the entire cockpit panel, not just a random wire from it.

.

and the ignition supply wire normally comes from the starter pos post, being feed from the start battery so this is where the fuse goes. at the starter. as this is the supply to the ignition swtich and start switch. I have never seen a fuse on the start solenoid line near the starter. the OP's fuse was likley in the supply line at start pos post. between starter and ignition. which is what he said.

[Dubble D]

All,
For clarity. I am referring to the wire from keyed switch to the starter solenoid. The one that sends a signal to solenoid in the momentary position. This is~14-16g wire. Now doing more homework, I do see that in the original wire diagram there is a 20a fuse in this line.
Guess I could have done homework prior to posting!
Did we drift a bit, maybe , at least we stayed at electrical! Great links sent out for all to view and learn.This will help me go further and install fuses where needed. I would much rather play with fuses than fire extinguishers.
And yes Stu the original fuse holder was `cleverly hidden` how did you know?
Going below to start tracing!

[MarkSF]

"I have never seen a fuse on the start solenoid line near the starter."

All the Universals have this by default. They had even painted the fuse holder Universal Gold!

By the way, there is very little point in removing an unreliable fuse, if you're going to leave two unreliable trailer connectors inline. Well, it's actually 4 connectors in the path, as the voltage to the solenoid goes through both connectors, two ways! Once to the panel, and once to the solenoid.

[Dubble D]

Originally Posted by MarkSF

"I have never seen a fuse on the start solenoid line near the starter."

All the Universals have this by default. They had even painted the fuse holder Universal Gold!

By the way, there is very little point in removing an unreliable fuse, if you're going to leave two unreliable trailer connectors inline. Well, it's actually 4 connectors in the path, as the voltage to the solenoid goes through both connectors, two ways! Once to the panel, and once to the solenoid.

Yep, point taken MarkSF. Two iffy trailer style connections do exist.
Here we go , off to digging deeper land!

[daveontheway]

Our 35 HP Yanmar has a 30A inline fuse to protect the solenoid circuit cabling several inches only from where it is connected to the starter cable. Also, while undertaking a rewire recently, I fitted new + battery terminals which incorporate Blue Sea 100A cube fuses. These give very neat fuse protection for both the + cable to starter and house electrics circuits.

[foufou]

Not certain if the wire cares what end the fuse is on. If the fuse opens the circuit he wire is saved

[DeepFrz]

Not certain if the wire cares what end the fuse is on. If the fuse opens the circuit he wire is saved

foufou, that is absolutely true. The wire doesn't care and if the fuse opens the wire is saved. However, if you have 29 ft. of unprotected wire and 3 inches of protected wire, you had better care.

[mitiempo]

Originally Posted by barnakiel

Whatever works.

With a 1.5 hp starter motor the amps induced at the first flash of a second the starter kicks in may easily blow up a 200 A fuse (on a 12 V starter, anyways). Plenty depends on how cold it is and what engine one has. A Westerbeke (if similar to those used in gensets) is way different from an old Volvo with an old school flywheel ...

I think maybe 200 / 300 A fuse is fine with lighter wires, but on my boat the wires are ... just imagine. Etc. So to say the size of the fuse, when present, will vary quite a bit between boats.

Big fuses are difficult to buy offshore. They are also difficult to fix (short) in a boat that may be rolling and pitching in the dark (that's exactly when such things happen - mostly at 04:00 hours).

Is it a good practice to have a circuit breaker on this circuit BTW?

I like the idea of protection on the starter circuit much as my boat came without one.

I regularly fuse starter circuits on diesel engines up to about 50 or 60 hp without any issues. I also fused a 6 cylinder diesel and there have not been any nuisance blows in the year since.

First you have to use large wires - usually i use 2/0 and never smaller than 1/0. Fuse for 2/0 is 250 amps and Anl or MRBF. An Anl fuse will handle more than 150% of its rating for 500 seconds. That's over 8 minutes. Since a starter is rarely engaged for more that 10 or 15 seconds there should never be a problem.

[Tempting Fate]

I'm in agreement with many other posts: the 'in rush' current to the starter can be 4-6 times the operating current, amounting to thousands of amps in some cases. Put a 300 - 400amp fuse close to the battery origin. It should be a 'thermal {melting} fuse' which will not have time to build up high temps before the engine starts.

[Elie]

In my opinion, a fuse installed in line(serie) on the load, all the circuit (from end to end!)will immediately affected by a change in amps.Therefore, a fuse placed anywhere in the circuit protect it. Naturally, it is important that the fuse be fast enough to blow before the any damage occur.