making new circuits from a dc distributing box

[paulga]

I want to source power from a dc distributing hub located on the portside. This hub is close to where the appliance (diesel heater) will be installed. This hub supplies power to the bow and stern thrusters. I have some ancor 10awg wires from amazon. The heat shrink terminals that I have are 10-12g with stud size 8, which falls small for the screws on that hub.

1. should I get a 8g lug terminal connector with a bigger ring hole to connect to the dc distributing box?

2. I want to install a recessed circuit switch on the cabin wall, like this toggle switch. Is there a round low key switch with an led indicator?

 

[Delta Riverat]

Just get some 10-12g crimps with larger rings, I know they are available in 1/4, 5/16 and 3/8.

Don't try to use an 8g lug on a 10g wire, not going to be secure.

 

[paulga]

I also want to add a fuse near the dc distribution box.
does a fuse's gauge need to match the wire gauge?
WM has an inline waterproof fuse holder, but it's compatible with 12-16g wires only. I didn't see a similar holder for 10g wires.
does this 14g fuse work?

 

[Portage_Bay]

I also want to add a fuse near the dc distribution box.
does a fuse's gauge need to match the wire gauge?
WM has an inline waterproof fuse holder, but it's compatible with 12-16g wires only. I didn't see a similar holder for 10g wires.
does this 14g fuse work?

View attachment 154854

A fuse doesn't have a gauge. It has a rating at which it blows, time to blow etc. The fuse is there to protect the wire. And you. It needs to be sized such that it blows before the wire ampacity rating is exceeded. Please spend some time on Blue Sea Systems web site studying fuses and wire ampacity before making your decision.

I seem to recall you are installing a diesel heater. It probably came with a fuse. The specs will surely tell you the required fuse size if it did not.

After you know the current demands of the heater start here Allowable Amperage in Conductors - Wire Sizing Chart

Then read about their fuses and make an informed decision.

 

[READY]

Whatever wire gauge is needed for the current and round trip distance should be the minimum that you use. OK to go with a larger wire (smaller AWG #). But not a good practice to try to couple 2 different gauge wires with a butt crimp connector. Fuse selection should be per the heater spec.

 

[O C Diver]

But not a good practice to try to couple 2 different gauge wires with a butt crimp connector.

Actually there are butt crimp connectors specifically designed for different size wires. In the attached pic, the yellow one is for normal yellow size to normal blue size, and the blue is for normal blue size to normal red size. The end with the ring is for the smaller wire size.

Ted

 

[paulga]

A fuse doesn't have a gauge. It has a rating at which it blows, time to blow etc. The fuse is there to protect the wire. And you. It needs to be sized such that it blows before the wire ampacity rating is exceeded. Please spend some time on Blue Sea Systems web site studying fuses and wire ampacity before making your decision.

I seem to recall you are installing a diesel heater. It probably came with a fuse. The specs will surely tell you the required fuse size if it did not.

After you know the current demands of the heater start here Allowable Amperage in Conductors - Wire Sizing Chart

Then read about their fuses and make an informed decision.

The fuse is near the battery to protect the wire loom and battery in case of short circuit due to chafe. The heater's fuse does not work for this purpose.

I mean the gauge of the fuse holder. they matched the 10g fuse holder with 40A fuse, 14g fuse holder with 15A fuse. if new circuit uses 10g wire (the ending section will be the heater's wire harness, that is much thinner, maybe 14-16g), can a 14g fuse holder like below be used? or should I pick the 10g one and plug in a15A fuse?

 

[paulga]

Whatever wire gauge is needed for the current and round trip distance should be the minimum that you use. OK to go with a larger wire (smaller AWG #). But not a good practice to try to couple 2 different gauge wires with a butt crimp connector. Fuse selection should be per the heater spec.

from the calculator a 12g and above should work. I'm going to use 10g wire that i bought.

 

[Portage_Bay]

As you said

The fuse is near the battery to protect the wire loom and battery in case of short circuit due to chafe. The heater's fuse does not work for this purpose.

Use the fuse that will protect the smallest wires in the circuit. You can put whatever fuse you need in the holder. If the fuse is rated less than the wire can handle but more than the heater requires you're good.

I mean the gauge of the fuse holder. they matched the 10g fuse holder with 40A fuse, 14g fuse holder with 15A fuse.

 

[paulga]

Actually there are butt crimp connectors specifically designed for different size wires. In the attached pic, the yellow one is for normal yellow size to normal blue size, and the blue is for normal blue size to normal red size. The end with the ring is for the smaller wire size.

Ted

is there a way to estimate the gauge of a wire to know what size of connectors to use?

I need to shorten the red wire and extend the wire to pump. For the extension i can use some barrier block that does not require connectors. But to shorten the red wire I'd like to use a butt splice terminal connector. Other than it has 32 strand count, the gauge is not printed on its insulation. In a previous post @Nick F mentioned a method of folding the higher gauge wires to match bigger wire barrels or barrier blocks. For what it's worth I'm still interested in how to determine the gauge accurately.

 

[SteveK]

Looks like 14 G

 

[Delta Riverat]

You can use a stripper and compare the various hole sizes with the conductor. You can verify by stripping a quarter inch. If not coming off easy, wire is smaller gauge, if cut strands, wire is bigger.

 

[O C Diver]

is there a way to estimate the gauge of a wire to know what size of connectors to use?

I need to shorten the red wire and extend the wire to pump. For the extension i can use some barrier block that does not require connectors. But to shorten the red wire I'd like to use a butt splice terminal connector. Other than it has 32 strand count, the gauge is not printed on its insulation. In a previous post @Nick F mentioned a method of folding the higher gauge wires to match bigger wire barrels or barrier blocks. For what it's worth I'm still interested in how to determine the gauge accurately.


View attachment 154878

If you're in doubt, try stripping off a little insulation and try a blue connector. If it doesn't go on, it will require a standard yellow connector, not the step down connector.

Ted

 

[jgwinks]

A fuse at the battery end of a circuit protects the wires. If there's a fuse at the device end it's to protect the device, but there must also be a fuse or breaker at the battery end. It's perfectly acceptable to put the device specified fuse at the battery end if that is the only device on the circuit. That's especially helpful if the device end fuse would be hard to access. If there's more than one device on the circuit, then there should be a fuse or breaker at the battery end appropriate to the circuit's wire gauge and whatever fuses are specified at each device.

 

[paulga]

A fuse at the battery end of a circuit protects the wires. If there's a fuse at the device end it's to protect the device, but there must also be a fuse or breaker at the battery end. It's perfectly acceptable to put the device specified fuse at the battery end if that is the only device on the circuit. That's especially helpful if the device end fuse would be hard to access. If there's more than one device on the circuit, then there should be a fuse or breaker at the battery end appropriate to the circuit's wire gauge and whatever fuses are specified at each device.

Does a 14g fuse holder drop more voltage than a 10g fuse holder?

The appliances has an ECU ic inside. Does this require a fast acting type of fuse?

 

[paulga]

You can use a stripper and compare the various hole sizes with the conductor. You can verify by stripping a quarter inch. If not coming off easy, wire is smaller gauge, if cut strands, wire is bigger.

Thanks for the idea.
I ordered a general tools wire gauge to determine the gauge according to this video

 

[jgwinks]

Does a 14g fuse holder drop more voltage than a 10g fuse holder?
I'm not sure but logically it might, slightly. The amount of voltage drop depends on the length as well as the gauge. More importantly, you would now have a piece of 14g wire in the circuit which would lower the allowable rating at the battery end. Unless you put a smaller fuse at the battery end I'd try to find a 10g holder. It's ok to fuse 10g wire at 15 amps, it's not ok to fuse even a very short length of 14g at 40 amps.

 

[paulga]

I'm going to use a 10g fuse holder on the battery side. On the heater side, if the red wire is 14g or lower, then there is no added benefit for using a 10g fuse holder, right?