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sailorboy1 · 03-05-2010, 15:05

Going thur old posts to do "closure" notes

Far as the hot lead to the switch or the motor first; The Rule switch I got first said to go to motor first (motor always hot). But I didn't really like the float switch itself and got a Water Witch because I felt it would be more reailable. The WW said to wire the hot to the switch first.

In the end I wired both switches with the hot going to the switch first. Installed with the WW as a lower/first and the Rule as an upper/second back-up float. Both wired via fuse directly tov the battery. So either switch operates the pump.

I also kept the orginal circuit via the electrical panel that I can manually run the pump with. Since this became a fair number of wires I used a terminal block to hook everything up.

In normal mode the water in my bilge should be at least 3' below the first WW switch because that's where the pump pumps down to.

Philsboat · 03-05-2010, 15:41

To eliminate wear on the bilge pump switch from dc currents,consider using a solid state switch which switches the load at 0 volts greatly increasing the life of the switch.I'll try to find a part number and manufacturer.

Phil

Philsboat · 03-05-2010, 15:46

SSRDC100V Series : Solid State Relays for Vdc Input/ Vdc Output

Here's a solid state relay that I used a lot when I was working.

Phil

perchance · 03-05-2010, 16:24

Rule #1 no spliced wires immersed in water no matter how well you think you've sealed them.
Rule #2 always switch the hot side

ishipaco · 15-05-2010, 16:14

Those posts recommending that your float switch should be installed in the "hot=+" side of the circuit are correct.

The reason is simple: switches, circuit breakers and other disconnect devices are properly installed in the hot side of a circuit in order to minimize the amount of the hot circuit wiring that is potentially exposed and could cause damaging leakage currents, even when the switching device is "off."

Keep in mind that "hot" and "ground" are relative terms. There are actually some old cars that use the + side of the battery as the "ground." In those cases, the whole situation is reversed. I only mention this in the interest of thoroughness; I've never encountered a boat that didn't have the negative side of the batteries grounded.

As an FCC-licensed marine electronics technician, I've worked on many wiring situations in boats. I abhor "butt" connectors in ANY circuits on a boat. Sure, they're easy to install, but almost always lead to problems down the road. In our boat, every splice is done like this: I strip insulation (about 1-11/2") from the end of each lead. Then I slip an ample length of shrink wrap (the more expensive kind with a melt liner inside) onto one of the wires. Next, join the two bare wire ends together with a western union splice. Then I solder the connection to enhance the mechanical strength and minimize the chances of developing a high-resistance point. Next, I completely coat the entire splice with 3M ScotchCote and let it dry. Lastly, I move the shrink wrap down over the splice and shrink it well, so that you can see the melt liner oozing out of both ends. Yes, I know that's a lot of work, but you only have to do it once. The splice will be water-proof and sturdy. Using this technique, I've never had a failed splice.

Therapy · 15-05-2010, 16:23

Quote:

Originally Posted by ishipaco

, every splice is done like this: I strip insulation (about 1-11/2") from the end of each lead. Then I slip an ample length of shrink wrap (the more expensive kind with a melt liner inside) onto one of the wires. Next, join the two bare wire ends together with a western union splice. Then I solder the connection to enhance the mechanical strength and minimize the chances of developing a high-resistance point. Next, I completely coat the entire splice with 3M ScotchCote and let it dry. Lastly, I move the shrink wrap down over the splice and shrink it well, so that you can see the melt liner oozing out of both ends. Yes, I know that's a lot of work, but you only have to do it once. The splice will be water-proof and sturdy. Using this technique, I've never had a failed splice.

That is how I have done it.
Slightly different matierials at times - availability/cost.
Never one failure either.

And I agree with

Quote:

Rule #2 always switch the hot side

**GordMay** · 15-05-2010, 16:37

Switch the positive.
Solder-only, including Western Union, terminations are not permitted.

chala · 17-05-2010, 23:04

Quote:

Originally Posted by ishipaco

Those posts recommending that your float switch should be installed in the "hot=+" side of the circuit are correct.

I disagree, it is about a float switch in extra low voltage, hardly "hot

" but it is a free world.

Maggie-K · 18-05-2010, 01:12

By the looks of the schematic the switch and the float are on + hot. Ground is not involved at all. And it appears to be a ABYC standard. Good post Jiffy.

ishipaco · 22-05-2010, 21:41

Chala said:

Quote:

Originally Posted by chala

I disagree, it is about a float switch in extra low voltage, hardly "hot

" but it is a free world.

Your meaning is not clear to me, but it sounds like you're saying something like, "since the concerned voltage is only 12V, there's nothing to worry about."

If so, I'm afraid you're terribly wrong. Current will flow through ANY conductor (e.g., wire, seawater) between two points of different potential. The relative polarities only determine in which direction the electrons will flow.

There is no such thing as a voltage differential that is too small to cause concern. Vessels can easily be sunk, caused by leakage currents of only a fraction of a volt! In fact, compared to the miniscule voltage differentials that commonly cause electrolytic corrosion (that's why we use sacrificial zinc anodes), 12VDC is VERY HOT indeed, and can cause rapid, catastrophic damage.

If I misunderstood your post, I apologize. Perhaps you can tell us what you're saying in a bit more detail.

**David M** · 22-05-2010, 23:44

By convention for DC circuits we choose the positive (anode) to be the supply and the negative (cathode) side to be the return, irrespective of which way the electrons are actually flowing.

If we wired our DC systems randomly where it did not matter if we used the anode or cathode as the source, then our DC electrical systems would be a mess.

We would essentially have to have two separate and electrically isolated electrical systems...the positive ground system and the negative ground system. Fortunately a convention has been chosen (negative ground) so we only need to have one DC system.

To get back to the original question, you always put the fuse and the switch before the load for a few good reasons.

chala · 23-05-2010, 22:30

Quote:

Originally Posted by David M

then our DC electrical systems would be a mess.

Yes for the one not used to complex installation. In the 60 , 70 the USA was a champion in including switches in active and neutral of control wiring. Until OZ refused to accept system who included switching of the neutral in control wiring this only to facilitate fault finding.

Quote:

Originally Posted by ishipaco

Perhaps you can tell us what you're saying in a bit more detail.

Quiet simple, has I hinted in a previous post, if a short circuit develop in a positively fed float switches it will blow the overload protection and there will be little chance that the pump cut-in. Further more it may remain un-noticed. But if the same happen in a negatively fed float switches it will not blow the overload, depending on the wiring, it may even raise an alarm but the pump will still remain operational.

convention are in general correct.

ishipaco · 05-06-2010, 22:11

Quote:

Originally Posted by chala

Yes for the one not used to complex installation. In the 60 , 70 the USA was a champion in including switches in active and neutral of control wiring. Until OZ refused to accept system who included switching of the neutral in control wiring this only to facilitate fault finding.

Quiet simple, has I hinted in a previous post, if a short circuit develop in a positively fed float switches it will blow the overload protection and there will be little chance that the pump cut-in. Further more it may remain un-noticed. But if the same happen in a negatively fed float switches it will not blow the overload, depending on the wiring, it may even raise an alarm but the pump will still remain operational.

convention are in general correct.

Please forgive me. I don't understand what you're trying to say. I'll let someone else take over. Bye.