Questions regarding a Blue Sea fuse block

[TheAxeman]

I installed a Blue Sea fuse block today under the seat and just had a couple of questions....

Is a 30 amp fuse appropriate to use as the main fuse off the battery?

How do I determine fuse sizes for various farkles? (Sirius radio, passport detector, powerlet, starcom)

What gauge wiring should I run to the powerlet socket?

Is a 14 gauge wire ok to run from the relay to a switched source?

 

[Rogue]

I would use #12 but it depends on the trmp rating of the wire insulation and where its going.

There is a chart HERE that may help you.

 

[Randy]

I used a 30a fuse from the battery. I also used 14ga from the Blue Seas box to the accessories.

 

[ionbeam]

Most general electrical/electronics are fused at 2x the rated current draw of the item. If your ElectroWidget is rated for 2 amps, fuse it at 5 amps (round up). If the ElectroWdget is rated for 5 amps fuse it at 10 amps.

 

[TheAxeman]

I truly appreciate the help. Its great to be able to post a question on this board and have an educated response within a couple of minutes. Thanks.

 

[antvq]

Its great to be able to post a question on this board and have an educated response within a couple of minutes.

You must be new here....... :lol:

 

[jestal]

If you have a doubt, short the circuit and see if the fuse blows before the wire smokes.....

No joke. The worst thing that can happen is the circuit gets a dead short and the fuse is the only thing standing between you and a crispy bike due to melting wire and flames. If you wire up the supply to the system and are afraid to short it then something is wrong. With all of my electrical modes and farkling, I always select what I think is the approapriate fuse and then deliberately short the farthest reach of the circuit to see that the fuse pops instantly before any wiring is damaged. Try it on a test circuit and see. The fuse has to pop to protect things and if you short it the fuse should pop with no damage. If something IS damaged (or you smell or see smoke or sense hot wiring) then the circuit is inadequate for the fusing and/or the fuse is too large for the wire you used. Better to find out now than on the road in the middle of the night.

Is the feed wire to the Blue Sea box fused?? That is as important as the fuses in the box as that long wire from the battery to the fuse box could short with disastrous results. I fuse one large feed from the battery (30 amps) to a junction block and then feed things like an auxilary fuse box in the rear of the bike from there. Each circuit from the Blue Sea box is fused but nothing protects the feed to the Blue Sea unless you fuse it at the source.

One way around this is to take the feed for the Blue Sea off at the starter solenoid terminal where the postive battery cable goes to. THAT is fused by the main fuse on the bike which should be adequate to protect a 12 gauge feed wire to the Blue Sea in the rear of the bike. Plus it takes a terminal off the battery post making battery connections easier.

 

[Constant Mesh]

jestal --

According to the FJR wiring diagram the starter relay connects directly to the battery -- it's unfused. So if you connect the Blue Sea feeder to the starter relay you have an unfused connection to the battery.

 

[jestal]

jestal --
According to the FJR wiring diagram the starter relay connects directly to the battery -- it's unfused. So if you connect the Blue Sea feeder to the starter relay you have an unfused connection to the battery.

Hmm....glad you are checking up on me. I better go back and look. There is a terminal that is fused off the main battery feed/main fuse I believe and I probably mixed it up in my memory. I was feeding several circuits off that area to avoid the battery post and thought at the time it might make a good alternative. Better go check...

I fused the circuits separately that I picked up off the starter relay battery post in any case so those are protected in case of a short and the fuses are accessible under the plastic panel in the right rear.

 

[Randy]

y'all are making this non-electronic goon nervous....I just did a straight run off of the battery with a 30a fuse on 10ga wire and ran it to a relay before going to the Blue Seas box. Did I do something wrong???

 

[ionbeam]

y'all are making this non-electronic goon nervous

I always select what I think is the approapriate fuse and then deliberately short the farthest reach of the circuit to see that the fuse pops instantly before any wiring is damaged.

WeelllHellll Jestal is making ME nervous. So, what happens to the wiring should the fuse NOT protect the circuit?

Randy, you done good!

About the only way to really screw things up is to use #28 wire with a 100 amp fuse The #28 wire becomes a heating element, burning off the insulation and igniting anything close by while the fuse just be chillin'.

When wiring general electrical/electronics, the Blue Sea fuse is only for catastrophic failures such as pinching a wire while lowering the gas tank or nicking a wire when clipping on the seats. When wiring in major power hogs like PIAAs which could be on a long time at high power you need to consider wiring and fusing a bit more careful. Still, most fuses are only for catastrophes and should never blow like happens when the toaster oven is on, the microwave is on and then someone turns on a hair drier. While farkling it is best to keep a limited number of items powered by 1 fuse (1 item/fuse is good!)

 

[TheAxeman]

I did like Randy and installed a 30 amp fuse directly off the battery useing 12 gauge wiring to the Blue Sea. I have read of others useing 10 gauge and a 50 amp fuse. Another question. Is there a difference between relays as far as waterproof or non-waterproof? The relay I bought was from NAPA, had the same terminal designations as other wiring diagrams I have seen, but doesn't quite physically look like the ones other folks have used. I explained to the NAPA counterperson what it was being used for and that is what he gave me. Better to ask the questions before I fire the mother up....

 

[ionbeam]

Axeman, your fuse & wire gauge is fine.

Did ya get a headlight/driving light relay? Does it have 4 numbered blades? Are there any holes in the case?

Headlight relay = :yahoo: 4 numbered terminals = :yahoo: Holes in the case = :angry2: If you were sold any relay for under hood use it will be fine. Most headlight relays have between 120 to 240 ohms resistance across the coil to minimize the power used to keep the relay energized. Other relays may have lower coil resistance and consume more power, it will still energize and function, it just sucks more valuable amps.

 

[TheAxeman]

Ion,

Not sure if its a headlight relay but it does have the four appropriately numbered terminals and no holes in the case but unlike some of the others does not have the small mounting tab on top. I simply mounted it in the plastic tray under the seat using industrial outdoor velcro. Its easy enough to change out if its wrong. I happened by Radio Shack yesterday and they had some relays marked only "automotive relay" that looked more like the ones other people have been using. Funny that the ones from RS were about $6.00 and the one from NAPA was $21.00.

 

[ionbeam]

You have the correct type relay. Be aware that the relay can get pretty hot. Some relays like Painless Wiring's relays don't have tabs. Some Bosch relays do and some don't have tabs based on current ratings of contacts. Good luck getting wired!

 

[double_entendre]

I used a 30a fuse from the battery. I also used 14ga from the Blue Seas box to the accessories.

So you're saying the 6 gauge I used is overkill? :glare:

But on the other hand, I didn't wire in a fuse there. I figured there was nothing in the world that would let the smoke out of those wires cables short of, well, a short direct to the engine or frame if the insulation got cut. I thought about putting in a circuit breaker and still have it in the garage.

Bob

Rancho Cucamonga, CA

 

[jestal]

WeelllHellll Jestal is making ME nervous. So, what happens to the wiring should the fuse NOT protect the circuit?

To answer your question: The same thing that would happen to it if it got shorted in the middle of the night by accident if it is not properly fused...it will cause smoke. As stated, better for it to happen now in the garage than on the side of the road in the dark.

I take the installation of spare circuitry and power feeds, especially like running a 12 guage wire from the battery positive post to the rear of the bike, pretty seriously because it can cause some pretty serious problems if it does get shorted or pinched or whatever. If you are afraid to purposefully short it when finished with the install then maybe you should feel uneasy about what might happen. Taking this approach makes the decision "to fuse or not to fuse" pretty simple. That is my basic point.

Besides, first hand experience is a good teacher....whether by accident or on purpose. LOL. Trying the purposeful short test on a test circuit is a good way to learn as stated.

 

[USMC CWO]

I'm preparing to install the Blue Sea 6-circuit fuse block myself. Since the maximum rating of the fuse block is 100 amps. should I install a 100 amp relay?

 

[kaitsdad]

I'm preparing to install the Blue Sea 6-circuit fuse block myself. Since the maximum rating of the fuse block is 100 amps. should I install a 100 amp relay?

USMC CWO, all you need is a 30 or 40 amp relay. You will need to fuse the hot lead from the battery with a 30amp fuse - this is the number you work with.