Texas Fishing Forum

Electrical Question

Posted By: TwoLakes

Electrical Question - 04/22/15 01:50 AM

Hi All,

I'm trying to understand my power pole pump wiring issues a little better. I'm not an electrician and don't understand why my pumps are wired this way and why the fuses are blowing. I have received a suggestion to move my in line fuses to the pump side of the circuit in the diagram below, but I don't understand why that would resolve my issue.

Issue: When I operate both my poles at the same time, both of my 40 amp in line fuses are blowing at the same time. When I operate the poles individually, they do not blow. The diagram below is a quick representation of the current wiring. Both pump hot wires are running through a single 50 Amp Circuit Breaker.



Questions:

Why would moving the fuses to the pump side of this diagram make a difference?
Should the circuit breaker be rated at 80 amps instead of 50 amps?
Why wouldn't the 50 Amp circuit breaker trip before the 40 Amp fuses blow?


I'm going to use a jumper to take the circuit breaker out of the equation. Each pump should then be able to pull 40 Amps like they need. If jumping across the breaker resolves the issue, I can get an 80 Amp circuit breaker. I would just like to understand why the fuses blow before the breaker trips.

Thanks.
Posted By: Lake Fork Guide

Re: Electrical Question - 04/22/15 01:56 AM

Take both power/ground to the cranking battery

Loose the breaker and go directly from pump to battery with am inline 40amp fuse

This is how it should be done
Posted By: Rickmb

Re: Electrical Question - 04/22/15 01:58 AM

How is everything grounded?
What else is connected to the batteries?
I would put circuit breakers on the pump side just to keep them separate if one goes bad.
Posted By: machinist

Re: Electrical Question - 04/22/15 01:59 AM

I would suggest that you rewire the power poles individually. Run you a wire from the battery
with whatever the proper amp circuit breaker to each power pole. I have never seen a circuit
breaker and a fuse together. I definitely wouldn't put a 80 amp breaker in. DC voltage doesn't
work that way.

Johnny
Posted By: TwoLakes

Re: Electrical Question - 04/22/15 02:11 AM

Thanks for the quick replies. I will do the following to test the system:

1. Remove circuit breaker.
2. Ensure positive/negative run directly to the cranking battery.

I assume the circuit breaker is in place so I can turn off power to the pumps when not in use. The pumps have a minimal draw. The circuit breaker is a quick way to turn the power off to both pumps. Does that explanation make sense?? I bought the boat this way, so I don't really know why it's there and I certainly don't understand DC Voltage. eek
Posted By: 04champ

Re: Electrical Question - 04/22/15 01:27 PM

I can't tell you why you're blowing the fuses, but I can tell you that it makes no sense to have a fuse rated less than the circuit breaker wired BEFORE the breaker. Move the inline fuses to between the breaker and the pumps
Posted By: SteezMacQueen

Re: Electrical Question - 04/22/15 01:35 PM

I'll shed a little light on fusing.

Fuses should ONLY be rated to the capacity of the wiring. Fuses protect the electrical SOURCE from the component. This why fusing is 99% of the time as close as possible to the battery or power distribution center(fuse panel). Fuse panels are not only for convenience, they also eliminate excess wiring from being in the circuit unprotected from the source of 12V+(battery). If a component has a built in fuse, then the fuse protects the component, not the wiring. Not the other way around. Circuit breakers are designed to prevent the component from drawing excessive amounts of amperage and damaging the component(power pole) The way this guys circuit is protected it adequate.

The wiring to the poles is likey correct. The wiring between the switches and source is likey the issue. The switches are reversing polarity type switches. If the switches are wired in a way that shares either 12V+,or 12V-, and either switch or source wiring is incorrect, this would send 12v+ to the other switches 12V- and break the fuse. Or vise versa.

Check the wiring before and at the switches.
Posted By: SteezMacQueen

Re: Electrical Question - 04/22/15 01:42 PM

If I had the boat to look at. I could solve this issue in about 15 minutes.

It is likely the switch(es), are faulty. A switch can perform its task (move one power pole up and down), and still be faulty. Faulty in the since that it isn't completely seperating from ground on the input side of the reversing polarity part of the switch, causing 12V+ to "see" 12V- on the other switches 12V+. Then, boom goes the fuses.
Posted By: PhishWhisperer

Re: Electrical Question - 04/22/15 04:17 PM

Originally Posted By: Lake Fork Guide-Cody Malone
Take both power/ground to the cranking battery

Loose the breaker and go directly from pump to battery with am inline 40amp fuse

This is how it should be done


^ This. And locate the fuses close to the battery(ies).
Posted By: Pearlandtexan

Re: Electrical Question - 04/22/15 06:19 PM

If you want to be able to turn the pumps off you need to install a larger breaker, with wiring large enough for that breaker. Install your fuses after the breaker. (this will protect the wiring to the pumps) My best guess is that why you are blowing fuses while using both pumps, is that the load for both pumps is greater then the rating of the 40a fuse, that's why they blow. If you do not want to buy a larger breaker, you can just put a perko switch in (that's what I have on mine) breaker is not needed, the two fuses is all you need. I AM an electrician btw.
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