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Old 10-04-2016, 06:20 AM   #21
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While undersized wiring MIGHT be a consideration, this is an existing system, so why are we even going there. This whole troubleshooting issue is getting way out of hand.
Lets not reinvent the wheel here. Just change the switches, and be done with it.
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Old 10-04-2016, 06:38 AM   #22
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I know in AC systems, If your not current limited in your power source, (relatively speaking to the load demands), the voltage going down means current will go up to keep the watts used about the same.

Battery being a limited power source, If your battery is depleted, drained, it wont be able to deliver the needed current or voltage.

A depleted battery wont cause a breaker to open, not seen that yet.
Interesting but I never really think about this.
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Old 10-04-2016, 06:50 AM   #23
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If you leave devices on till the battery fies, not all loads will trip the breakers....things like lights wont....depends on what the load is.

Corrosion in a switch is adding resistance just in the switch....even resisters have to dissipate heat.

You guys are arguing apples and oranges....thsts why the difference of opinion I think.
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Old 10-04-2016, 08:55 AM   #24
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I know in AC systems, If your not current limited in your power source, (relatively speaking to the load demands), the voltage going down means current will go up to keep the watts used about the same.......... .
Obviously, you do not know electricity as well as you think you do.

It's not my job to teach someone electricity 101, especially if they refuse to learn. An appliance cannot "keep the watts used about the same". The possible resistance of the switch will cause a lower voltage at the appliance and the appliance will draw less power. The only way to keep the power the same at the appliance with the added resistance of the switch would be to raise the voltage to compensate for that lost to the resistance of the switch. How are you going to do that?

The whole argument is pointless anyway. He could have driven to West Marine, bought the switches, returned to the boat, installed them and had a couple beers by this time.
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Old 10-04-2016, 09:08 AM   #25
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I know in AC systems, If your not current limited in your power source, (relatively speaking to the load demands), the voltage going down means current will go up to keep the watts used about the same..
Following this "logic", if the voltage goes down to zero, the current would be infinite, right?

Not going to happen.
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Old 10-04-2016, 09:42 AM   #26
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If the switch gets hot either the contacts in the switch are bad or the wire lugs connected to the switch have some corrosion in them. Replace the switch and crimp on new lugs. No Ohm's law required.
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Old 10-04-2016, 09:45 AM   #27
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BobH is right, just replace the darn things. Cole Hersee and Carling are two good switch brands.
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Old 10-04-2016, 10:24 AM   #28
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If the switch gets hot either the contacts in the switch are bad or the wire lugs connected to the switch have some corrosion in them. Replace the switch and crimp on new lugs. No Ohm's law required.
And that's what I suggested in post #14.
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Old 10-04-2016, 10:27 AM   #29
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Someone above posted a question, bears repeating:

Do switches have indicator lights??
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Old 10-04-2016, 10:33 AM   #30
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Obviously, you do not know electricity as well as you think you do.

It's not my job to teach someone electricity 101, especially if they refuse to learn. An appliance cannot "keep the watts used about the same". The possible resistance of the switch will cause a lower voltage at the appliance and the appliance will draw less power. The only way to keep the power the same at the appliance with the added resistance of the switch would be to raise the voltage to compensate for that lost to the resistance of the switch. How are you going to do that?

The whole argument is pointless anyway. He could have driven to West Marine, bought the switches, returned to the boat, installed them and had a couple beers by this time.
I was not talking about his or any switch in that post I made. You'r going way beyond what I said to try and push your point in saying I know little about electricity??

Where is the word switch in my post??
I know in AC systems, If your not current limited in your power source, (relatively speaking to the load demands), the voltage going down means current will go up to keep the watts used about the same.

Battery being a limited power source, If your battery is depleted, drained, it wont be able to deliver the needed current or voltage.

A depleted battery wont cause a breaker to open, not seen that yet.
Interesting but I never really think about this.


Curious do you think of yourself as having bully tendencies? Hey, don't take this this the wrong way and get angry.
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Old 10-04-2016, 11:54 AM   #31
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I know in AC systems, If your not current limited in your power source, (relatively speaking to the load demands), the voltage going down means current will go up to keep the watts used about the same.
How is the AC device able to control the watts? That makes absolutely no sense unless it's an electronic device with a switching power supply which might be able to control the duty cycle to draw more amps. For a simple AC device, lights, motors, etc. that is just not possible.

To add to my previous post, if the boat is wired with plain copper wires, not tinned wires, chances are the resistance is in the corroded crimped on lugs. had the same issue on our boat, solved it by cutting off the old lugs, stripped the wire back to get to some clean copper and crimped on new lugs.
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Old 10-04-2016, 12:01 PM   #32
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Originally Posted by psneeld View Post
If you leave devices on till the battery fies, not all loads will trip the breakers....things like lights wont....depends on what the load is.

Corrosion in a switch is adding resistance just in the switch....even resisters have to dissipate heat.

You guys are arguing apples and oranges....thsts why the difference of opinion I think.
Yes it is an apples (series circuit) to oranges (parallel circuit) argument.
Total current will go up in a parallel circuit as you add resistance. My example of seeing your amp meter go up as you turn stuff on.
But in a series circuit, current will go down when you add resistance.

I agree, just replace the switch.
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Old 10-04-2016, 05:11 PM   #33
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Appreciate all of the info. Real life got in the way and I haven’t had the chance to get back to the boat to implement several of the good suggestions presented.

Al/Ski – no indicator lights.

DHeckrotte – may be size limited on the sealed switches – have 9-10 in a row, cheek by jowl – may not have space based on what I’ve looked at on line.

sdowney717 – never knew you could buy a sealing boot – or the name of that doomahitchee.

Toolbuddie – going to do that when I get back for my own education.

WesK, Parks, FOG – Remove and replace, that’s the plan. If there’s still a problem, I’ll investigate further downstream.
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Old 10-04-2016, 08:39 PM   #34
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Yes it is an apples (series circuit) to oranges (parallel circuit) argument.
Total current will go up in a parallel circuit as you add resistance. My example of seeing your amp meter go up as you turn stuff on.
But in a series circuit, current will go down when you add resistance.

I agree, just replace the switch.
Any resistance in the switches would increase the resistance in this series circuit and lower the current. Nobody would add "resistance" in parallel because that would not make sense. Someone might add another light, blower, etc. and the current would increase to supply these added loads.

Even with multiple appliances, this part of the circuit (the switch) is a series circuit. The switch is in series with the load(s).
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Old 10-04-2016, 10:12 PM   #35
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Remove and replace, that’s the plan. If there’s still a problem, I’ll investigate further downstream.
How about tearing into those switches with a cellphone camera handy to show us the condition inside? I've never seen the inside of a bad marine switch.
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Old 10-05-2016, 12:54 AM   #36
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Any resistance in the switches would increase the resistance in this series circuit and lower the current. Nobody would add "resistance" in parallel because that would not make sense. Someone might add another light, blower, etc. and the current would increase to supply these added loads.

Even with multiple appliances, this part of the circuit (the switch) is a series circuit. The switch is in series with the load(s).
Are you sure you want to make this statement?
It conflicts with your next sentence.
When someone adds another light, blower, etc. they are adding resistance in parallel. These added loads are resistance. As I have said before, turn stuff on and watch the amp meter go up. Each time you turn something on in your boat it adds another resistive parallel circuit.

Agree the switch is in series with the load. But disagree that the switch is in series with the loads (more than one load). Also, not sure what you mean by the first sentence. Maybe an example to help me understand.

A series circuit is not practical on a boat.
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Old 10-05-2016, 05:59 AM   #37
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How is the AC device able to control the watts? That makes absolutely no sense unless it's an electronic device with a switching power supply which might be able to control the duty cycle to draw more amps. For a simple AC device, lights, motors, etc. that is just not possible.

To add to my previous post, if the boat is wired with plain copper wires, not tinned wires, chances are the resistance is in the corroded crimped on lugs. had the same issue on our boat, solved it by cutting off the old lugs, stripped the wire back to get to some clean copper and crimped on new lugs.
Voltage drop, amperage increase? - electricity electrical engineering | Ask MetaFilter
Just a myth I suppose.

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Motors (or compressors or whatever) also pull more current when the voltage drops as they still try to do the same amount of work.

Pretty much any computer, amplifier, or other electronic device with a modern power supply will draw more current when the line voltage drops. This is because the power needed by the device is constant (or at least not related to line conditions), and power = voltage x current. So if voltage goes down, current must go up to compensate.
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Old 10-05-2016, 08:38 AM   #38
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Are you sure you want to make this statement?
It conflicts with your next sentence.
When someone adds another light, blower, etc. they are adding resistance in parallel. These added loads are resistance. As I have said before, turn stuff on and watch the amp meter go up. Each time you turn something on in your boat it adds another resistive parallel circuit.

Agree the switch is in series with the load. But disagree that the switch is in series with the loads (more than one load). Also, not sure what you mean by the first sentence. Maybe an example to help me understand.

A series circuit is not practical on a boat.
1) A wire from the battery, through a circuit breaker, through a switch, through a light bulb or blower and back to the battery is a series circuit.

2) Extra lights, blowers, etc. are wired in parallel and do increase the current flow in the circuit but if the switch controls them all, the switch is in series with the load (the lights and blowers). Any resistance in the switch lowers the voltage available to the load and lowers the total current.
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Old 10-05-2016, 09:11 AM   #39
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Pretty much any computer, amplifier, or other electronic device with a modern power supply will draw more current when the line voltage drops. This is because the power needed by the device is constant (or at least not related to line conditions), and power = voltage x current. So if voltage goes down, current must go up to compensate.

Let's try to have a little common sense here. We're not talking about a regulated computer power supply, we are talking about a common light bulb or blower motor.
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Old 10-05-2016, 09:24 AM   #40
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Let's try to have a little common sense here. We're not talking about a regulated computer power supply, we are talking about a common light bulb or blower motor.
This was just an example of how when voltage falls current rise to keep the total wattage the same.

I have a digital volt-amp gauge on my shore line.
When running the heat pump, I have seen when voltage drops the amps used do go up.

I have free 30 amp marina power, but it is shared to several boats along the pier, so when people use power available volts drop. So when I am running my AC, it is easy to see, plus if I run something else in the boat, I also see it happen. Worst it can get is down to 100 vac.
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