Blue Sea Systems Fuse Block Wiring Help

[njy229]

I ordered the Blue Sea Systems split fuse block (https://www.bluesea.com/products/5032/ST_Blade_Split_Bus_Fuse_Block) but it had no directions on how to wire it.

I plan on using Block A for constant power and Block B for accessory. I will likely have more questions when I add some relays but as a starting point does the wiring in the pic look ok?

Can I run a wire from terminal A to terminal B instead if running a second wire from battery POS?

Can I ground the fuse block to the body or would running a cable back to battery NEG be better?

Would this relay work for block B? https://www.amazon.com/dp/B073H4RBFN/ref=cm_sw_em_r_mt_dp_U_kbwvEb464B9YR

 

[.94 OR]

I would use something like this:

https://www.amazon.com/CONTINUOUS-S...ive&sprefix=100+amp+con,automotive,213&sr=1-7

between the A and B with a key on trigger for the second half of your fuse panel. I'm worried the relay you linked to is an intermittent relay and would not live long being energized the entire run time of the engine.

 

[Jfryjfry]

The wiring will work just fine. Running your ground to the battery is “better” but unnecessary. The body is fine, provides your battery has a good negative path to the body.

That relay, as mentioned, is a starter relay. I’m unfamiliar with them and can’t say if they’d work it not. And are you sure you need 100a capacity on that circuit? Thats am awful lot.... I used a 50amp relay ($20 for 5 with wired sockets) in the same setup.

 

[njy229]

.94 OR - Appreciate the suggestion

Jfryjfry - I thought the 100 amp relay would be overkill since I only have a couple items to run off the fuse block for now, I wasn't sure if I should overbuild for additional items down the road.

 

[DirtDonk]

Overkill can be good.;D
But in this case it's probably not necessary either. The whole 12 circuits are maxed out at 100a according to the rating. That means that in theory at least your panel A is good for only a 50a max.
But since working something to it's max rating is rarely a best-practice, using a heavier duty than normal relay seems a good move. So something at least rated at 70a would be a good thing. Nothing wrong with 100a either though, if we're thinking along those lines.
Continuous duty required for sure.

Paul

 

[68ford]

http://www.jegs.com/i/Dedenbear/302/BAR/10002/-1

In use these 75amp relays when your standard relays load capacity is in question, but a "constant duty solenoid" is too much.

 

[chuckji]

Curious, why would you have a grounding terminal in the fuse box?
Typically, you would ground devices to the vehicle chassis near or close by the device, or in some cases directly back at the battery.
It would seem unusual to run a ground wire all the way back to a fuse box - just to connect to a ground point that you've grounded to the chassis near the fuse box.

I think this might make sense if this box is installed in a boat where everything is fiberglass and there is no metal "chassis ground", but an automobile is different.

 

[DirtDonk]

That's exactly what it's for. A common grounding area in case it makes sense. On most automobiles it does not, but as you say, a fiberglass boat (which is what BlueSea stuff is designed around after all) is much more likely to need a path.

Paul

 

[Jfryjfry]

I didn’t realize they made a split one. I made one. https://grassrootsmotorsports.com/f...rpose-fuse-box-so-i-created-one/153972/page1/

I removed the grounding bracket and put it behind the dash as a clean way to ground stuff.

 

[njy229]

One reason I asked about the relay that I linked to in my first post was because it had posts that I could easily connect to. I thought about a 70 or 80 amp relay but I can't seem to find the larger spade terminals that slide onto those and the relays that come with socket plugs seem to have 12 and 10 gauge wires on them. The chart I'm looking at says to use at least 6 gauge wire for 50 amps. I wasn't looking to buy a 50 pack of terminals when I only need 2 of them.

 

[Jdgephar]

Another option is to eliminate the 100 amp relay. Wire both A and B right to the battery. Use individual small relays after the fuses on the B side that are all switched on by the ignition key.

Sent from my SM-G950U using Tapatalk

 

[Steve83]

The best way to wire anything (boat, car, golf-cart...) is to run all the negative/return wires back to the battery through Copper the whole way. Using a conductive (steel, Aluminum) body or chassis as a ground is a cheap way to avoid buying as much wire. But it risks problems everywhere the Copper connects to the ground metal, and each of those connections is subject to insertion loss. Eliminating them is better. If the body is conductive, it should still be grounded, but only for RFI; not for power distribution.

If you want a master relay, it needs to be specifically rated for continuous duty.

 

[charlie6976]

On having a grounding point for each positive 'post', those with fiberglass bodies will appreciate. I have one.