relay wiring question

[minst7877]

I'm installing a fuse block on my bike and have this relay that I want to use. The schematic on the relay looks like this.



How does it need to be wired? Is this right?

85 to the accessory circuit
86 to ground
87 to fuse block
30 from Battery

[Blueraven]

30 to the POSITIVE terminal of the battery
87 to the AUX block
85 to your switched power
86 to the ground.

So YES.

[Jared]

Here is a nother electrical question. How do you know what gage of wire to use? If there is a fuse in place does it matter?

[Blueraven]

Yes it does. For 30A, you should use between 14 and 16 gauge wire. Your fuse should match the current. Anything smaller, your wire will melt or burn.

[ve3hzz]

Originally Posted by Utah Motorcyclist

Here is a nother electrical question. How do you know what gage of wire to use? If there is a fuse in place does it matter?

YES. First depends on what you need for the MAIN power coming FROM the battery and going TO the accessory you are powering. If for example you are powering a set of driving lights then a 10 gauge wire would be better or a 8 gauge to handle the current. Since the relay will handle up to 30-40 amps (most automotive) and then you put in a 10 amp fuse in line it will protect the rest of the circuit and blow first. If for example you are using it to connect via a fuse box (aux) then using an 8 gauge wire with say a 25/30 amp fuse would protect the main circuit and then each fuse in the aux fuse block would protect each individual and overall draw would (should not) exceed the max of the main fuse (of that relay). Also check the relay some have it so that 85 is ground and 86 is the switching circuit (as in power to a tail light etc) as there is a switching diode to protect from a reverse circuit powering back through the relay.
I used 10 gauge wire from the battery to the aux fuse block for unswitched power and 10 gauge from that to the relay and then to the switched aux fuse panel (I wired up 2 one for each as had them already).

[Blueraven]

As Scotts says, 8 gauge is from the battery to the fuse panel. 14-16 gauge will handle 15 amps. I used that gauge for all my wiring of the accessories. I am fusing my head lamps at 10Amps so 14 gauge was a bit of overkill but no harm done.

[Jared]

Okay, so if I use a 10 gage to go from the battery to my fuse box and then a 14 to each of the accessories, I should be good?

I am completely clueless about this type of stuff. Why couldn't I use a thinker gage, like the 10, to wire up the accessories?

[ringadingh]

Take a look in the tech section, there is a schematic there to look at.

[Jared]

Originally Posted by Ringadingh

Take a look in the tech section, there is a schematic there to look at.

Thanks Ring!

[minst7877]

Thanks for the help with this. If what I am reading is sinking in the circuit to my light bar should be fused with a 15 amp fuse on #14 wire. What size fuse and wire are you using for your accesory plugs? Currently only plan on using the GPS and phone charger on it. I'm thinking 10 amps with #16 wire? Will be using #10 from Battery to relay and over to the panel with a 30 amp inline fuse before the relay.

From the tech link.
"In summation:

For a 10 amp fuse use 16 gauge wire.
For a 15 amp fuse use 14 gauge wire.
For a 20 amp fuse use 12 gauge wire.
For a 30 amp fuse use 10 gauge wire."

Thanks for the help think I'm headed in the right direction now.

DC

[ve3hzz]

Originally Posted by minst7877

Thanks for the help with this. If what I am reading is sinking in the circuit to my light bar should be fused with a 15 amp fuse on #14 wire. What size fuse and wire are you using for your accesory plugs? Currently only plan on using the GPS and phone charger on it. I'm thinking 10 amps with #16 wire? Will be using #10 from Battery to relay and over to the panel with a 30 amp inline fuse before the relay.

From the tech link.
"In summation:

For a 10 amp fuse use 16 gauge wire.
For a 15 amp fuse use 14 gauge wire.
For a 20 amp fuse use 12 gauge wire.
For a 30 amp fuse use 10 gauge wire."

Thanks for the help think I'm headed in the right direction now.

DC

OK I'll make this quick as I gotta leave for work. First, the driving/fog lights use the gauge wire for amps to ensure you don't get the wire warm from passing too much current, but in those 55 watt lights you only need a 10 amp fuse. It is designed to blow to protect the rest of the circuit and wiring including the lights. If you say run a 15 amp fuse in a wire that can handle UP to 15 amps of current, then the wire (if draws too much) can become hot and melt insulation before the fuse blows!!! Remember that as the wire ages it becomes more resistant. You don't want to run a bigger fuse then is required. Think of your home, and in a normal circuit instead of a 15 amp breaker you put in a 30 When would the breaker trip? AFTER a potential dangerous short..or never. Wire would give up first (likely).
So use the wire gauge to ensure that you have enough capacity and use the fuse of the proper rating to protect the circuit and not OVER kill. I've seen many put in a larger fuse to stop popping them instead of fixing the problem!!!! Please don't do that......

OK????
Oh and using a slightly larger gauge fuse then is required for a circuit won't hurt anything, too small a gauge will. But bigger the gauge wire the more it costs, another reason you see smaller wires when larger ones aren't needed.

Scott

[Blueraven]

Just one other quick note. ALWAYS have a fuse in circuit for ANYTHING that requires power and as close to the POWER SOURCE as possible so that if there is a short anywhere, the fuse will take the brunt of it. You run the risk (like the person before me that had the bike and didn't fuse circuit) of burning wires. I had to rewire all my accessories because of that.

[Dave]

http://www.autoshop101.com/forms/hweb2.pdf

[minst7877]

I have started to mount the relay and fuse block under the left side cover. This is what it looks like so far. Need to pick up some different size fuses but so far I like it.

DC

[ve3hzz]

Originally Posted by minst7877

I have started to mount the relay and fuse block under the left side cover. This is what it looks like so far. Need to pick up some different size fuses but so far I like it.

DC

That is what my aux fuse block looks like One of them is in that location and the other...well once done. I'll post pics but similar layout...LOL...great minds think alike

Scott