Wiring Diagram Review

[maccauley123]

How is it that you get a high amp fuse within 7 inches of the battery? All I have seen are the two post fuses. Do I get a 6 inch long battery cable, run this from battery post to fuse block then run a cable to battery switch?

Is there a high amp fuse that I can connect right to the positive battery post then run my cable off of this? I have not seen anything like this.

[sailingdog]

Mac-

You can use either of these:

Blue Seas Bls5001 Block For Mega Fuse 100 - 250a



or

Blue Seas Bls7102 Circuit Breaker 100 Amp Sfc Mt



The way I did this on my friend's boat is I mounted the Circuit Breaker on the outside of the battery box. That way the actual run between the positive post and the circuit breaker is about a foot long, and the rest of the run is protected.

[peikenberry]

Thanks Sailingdog; I 'll check that out. I used have five different browsers to make sure my web site opened ok, but I dumped three of them. I have a link to Alden Trull on my site, so I'l put a note under it.

[peikenberry]

As for the distance overcurrent protection must be from the source of power, remember the overcurrent protection is there to protect the wire, not the equipment. So it needs to be close to the source. There is an exception. If the wire is contained in a loom, conduit, or sleeve (insulation doesn't count as a sleeve) it can be up to 40 inches away. Here's what both the regulation and ABYC standard says: "If it is physically impractical to put the fuse or circuit breaker within seven inches of the source of the power it can be up to 40 inches (101.6 cm) away, if the wire is contained for it's entire length between the source of power and the circuit breaker, in a sheath or an enclosure."

So if there is a problem and you can't get the fuse or circuit breaker within 7 inches you can move it farther away if you sheath it. There is some great flame retardent wire loom on the market made for use on boats. Here's an example. Wire loom, Cable tubing, Wire organizer from Cable Organizer

[sailingdog]

Peter-

Glad to help out.

Basically, if the wires are protected by conduit, loom, sheathing or some other way, the fuse/circuit breaker can be further away, since the wire isn't likely to get cut and shorted out.

[peikenberry]

That's right.

By the way I checked it out and the Alden Trull site only opens correctly in Internet Explorer and another browser called Enigma. I doesn't work right in Mozilla, Netscape, Opera or Safari.

[sailingdog]

Safari, Netscape, Opera and Mozilla are open-standards compliant browsers... Go figure.

[hellosailor]

Those fuse blocks sd posted, can be mounted directly on the battery with size 00 lag bolts, right into the side of the case and through the plates.

KIDDING!

But Scotch exterior-grade double-sided tape, or hot melt glue, or a good adhesive caulk, or the self-adhesive industrial strength velcro, will all make reasonable alternatives. Or you can mount them to a small plate, make a 3/4" hole in it, and let the battery terminal itself stick up through the hole to "anchor" the plate. All sorts of ways.

SD, unless that breaker is one of the special ones that can carry a 5000A surge without fusing shut--it isn't for battery primary service. The conventional breakers all arc shut (useless) with loads around 3500A, and a good battery can put that out into a dead short. The good breakers are damn closed to $100 each.

[sailboy21]

I, for one, think the schematic posted looks just about right for a small boat. The only comments I have, is 10AWG wire is pretty big, probably not necessary for loads from your 30 amp panel. My boat has a refer, 12 cabin lights, 2 water pumps, 2 blowers, radar, gps, VHF and I have never exceeded even 20 amps from the main panel. I do have other loads that bypass the panel, SSB (20 amps at full output) and 3 bilge pumps that skip my panel and are fused/breakerd independently from the ammeter and panel. This is obviously not a panel for an energy intensive boat.. therefore 4 gage (160 amps max) seems more than adequate for two house banks which are likely nor more than groups 31(???), and 10 AWG wire should be about twice what would be required to safely blow your panels fuse... just a thought. Heavy wire is expensive and hard to run.. I am more than comfortable used 14 or even 16 AWG for my cabin lights no lost sleep for me!

[Hartley18]

Something else to keep in mind:

When installing fuses/circuit breakers/whatever near the batteries, please make sure there are no flammable materials (wood, fibeglass, rubber) within several inches of the wiring - when a fuse blows, lots of heat (and sometimes molten metal) is produced... and we don't want the boat catching fire now, do we?