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Old 06-18-2018, 12:42 PM   #1
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best large to small wire connection?

Folks,

A basic question. I have a head with a 12 ga wire coming out of it and have to run quite a distance to the panel board. The head draws 16 amps so the tables tell me to use a 6 ga wire.

What is the best way to step up from 12 ga to 6 ga at the head end, and then down enough so I can hook up to my breaker? do they make a ready connector for that?
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Old 06-18-2018, 12:51 PM   #2
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I donít like to connect two sizes of wire directly to each other. In your case Iíd use a terminal block.
https://www.bluesea.com/products/260...5A_-_2_Circuit
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Old 06-18-2018, 01:07 PM   #3
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Quote:
Originally Posted by HopCar View Post
I donít like to connect two sizes of wire directly to each other. In your case Iíd use a terminal block.
https://www.bluesea.com/products/260...5A_-_2_Circuit
+1.
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Old 06-18-2018, 01:11 PM   #4
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Folks,

A basic question. I have a head with a 12 ga wire coming out of it and have to run quite a distance to the panel board. The head draws 16 amps so the tables tell me to use a 6 ga wire.

What is the best way to step up from 12 ga to 6 ga at the head end, and then down enough so I can hook up to my breaker? do they make a ready connector for that?
6ga wire for 16A sounds like overkill - are you sure about that requirement? How far are you running that?

http://assets.bluesea.com/files/reso...ence/21731.pdf
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Old 06-18-2018, 03:23 PM   #5
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It's a 16 amp load with a distance from the battery to the head of 32 ft.

The head pump kept tripping the breaker if run for any time, looked at the PO wires - all 12 ga from the head to the panel board - uh oh.
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Old 06-18-2018, 03:31 PM   #6
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I see 4 to 2 gauge for that distance. This is the correct chart. Make sure you install the correct load protection too.
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Old 06-18-2018, 04:30 PM   #7
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Seems to me the suggestion of a terminal block is the best one. There is nothing that I know of that will properly directly connect a 12 to a 6 gauge. And has been said, mind the proper use of overcorrect protection.

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Old 06-18-2018, 05:16 PM   #8
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Originally Posted by HopCar View Post
I donít like to connect two sizes of wire directly to each other. In your case Iíd use a terminal block.
https://www.bluesea.com/products/260...5A_-_2_Circuit
X3.

Out of curiosity, what kind of head is that?
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Old 06-18-2018, 05:20 PM   #9
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I see 4 to 2 gauge for that distance. This is the correct chart. Make sure you install the correct load protection too.
Huh? Look again. A head pump motor is not typically a critical voltage drop item.

First question is, however, what is the roundtrip distance from the breaker?
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Old 06-18-2018, 05:38 PM   #10
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X3.

Out of curiosity, what kind of head is that?
Must be one for a giant ass,16amps is a huge amp draw in my sense!

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Old 06-18-2018, 05:44 PM   #11
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Old 06-18-2018, 05:48 PM   #12
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I have #4 wire feeding the head for the Lectrasan. Total round trip lengths is maybe 12 foot.
Of course the lectrasan has a terminal block on top and much small wires running all over.


The head itself, with its built in macerator, voltage drop not been an issue. Just a standard 12 gauge wire back to the breaker.
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Old 06-18-2018, 06:10 PM   #13
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LOL! So not enough holding tank for these invites !

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Old 06-18-2018, 06:21 PM   #14
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Terminal strip is the best answer. In cases were that wasn’t practical l have used spade connectors.
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Old 06-18-2018, 08:15 PM   #15
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The head is a Jabsco 37010, 12V.

The draw is 16 amps.

I have been calculating the distance from the pump to the power source (battery) X 2.

Using the calculator at Circuit Wizard - Blue Sea Systems I used a 5% voltage drop, not critical, but motors do not like low voltage
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Old 06-18-2018, 09:21 PM   #16
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The SPX AquaT macerator toilet I bought has a table suggesting a 25 amp breaker and #8 for 40' - 60' run distance.


Did yours come with an installation document with electrical requirements?
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Old 06-18-2018, 09:24 PM   #17
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Quote:
Originally Posted by PMF1984 View Post
It's a 16 amp load with a distance from the battery to the head of 32 ft.

The head pump kept tripping the breaker if run for any time, looked at the PO wires - all 12 ga from the head to the panel board - uh oh.
Is the cable routing distance the round trip distance or one-way?
Assuming 32 ft round trip:
Round up to 20 amp load (conservative)
Round up to 50 feet length (conservative)
A head is a 10% voltage drop load
From the chart... is #10 AWG. (conservative)

Assuming 64 ft round trip:
Round up to 20 amp load (conservative)
Round up to 65 feet length (conservative)
A head is a 10% voltage drop load
From the chart... is #8 AWG. (conservative)

If #6 will make you feel better, then go for it!
As far as the tripping breaker goes;

1- What is the amp rating on the breaker, and

2- What is the measured current with an ammeter when the breaker trips?

(This is why I always say a cruiser needs to have a clamp-on DC ammeter on their boat for troubleshooting problems. Otherwise we're all just guessing.)
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Old 06-18-2018, 09:48 PM   #18
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Does the wire to the head run to the battery or to a breaker panel? Hopefully the breaker panel is closer to the head? Only the main feed to the breaker panel and the bilge pump connect to the batteries.
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Old 06-18-2018, 10:28 PM   #19
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No reason to run 6 AWG wire for a 16 amp load.

I have no problem with 12 AWG, but if you want to run 10AWG that would work as well.

Going back to your originally reported problem which is ths head tripping the breaker Iím thinking that the wire size is probably not your problem.
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Old 06-18-2018, 11:50 PM   #20
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I always go for critical voltage - why not? A head is a critical voltage, nothing like killing your only toilet out in an anchorage. Gives you one size larger cable and the extra cost will be forgotten in a week after you install it. Besides, what happens to the wire run when your batteries are 12.2 not 13.5 or so and you run the head?

Do the runs for 64 feet and 16 amps? Its obvious to me.

RT, that rhino puts the no-discharge rule in perspective, doesn't it? I wonder how much volume a humpback whale produces?
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