Battery cut-off switch

[Maine Sail]

Originally Posted by Hartley18

Maine, it's interesting then that many commercial off-the-shelf bilge pump control panels (like the one below, currently fitted to my boat) are negative switched - that's one reason so many people have problems hooking them up!



1. Are you saying a commercial purpose-built product doesn't meet the standards??

2. Do you seriously expect a competent surveyor to inspect the entire wiring system on a boat - looking for circuits that might be negative switched??

No. I didn't think so.

Our US switches are not negative switched but rather positive.

"ABYC E-11

11.14.2. FOR DC SYSTEMS

11.14.2.1. If single pole switches are used in
branch circuits they shall be installed in the positive
conductor of the circuit.connection


11.7.1.2. BATTERY SWITCH

11.7.1.2.1. A battery switch shall be installed
in the positive conductor(s) from each battery or
battery bank"


Of course I am only guessing the OP is in the US but he may be elsewhere where the standards are different or perhaps there are no standards...

[SEMIJim]

Originally Posted by Hartley18

Maine, it's interesting then that many commercial off-the-shelf bilge pump control panels (like the one below, currently fitted to my boat) are negative switched - that's one reason so many people have problems hooking them up!

That switch/fuse module has two wires going in and two wires coming out, or two sets of terminals, in either case each marked "+" and "-", and the switch is on the "-" side?

Who makes that thing?

Jim

[mitiempo]

If it is true that the switching is negative it means that there are always 2 hot wires in the bilge. With engine and its attachments being the common ground and also in the bilge that sounds like a problem waiting to happen.

[Hartley18]

Originally Posted by mitiempo

If it is true that the switching is negative it means that there are always 2 hot wires in the bilge. With engine and its attachments being the common ground and also in the bilge that sounds like a problem waiting to happen.

Well.. one hot wire at least.

I don't have the manual for my specific one with me, but this is what I find on the web for something similar (ie. cheap!!):





Note that the fuse is in the negative return and positive is applied to the bilge switch whenever it's in 'auto'. I'd still call that 'negative switching' because if the fuse blows ("switches") then you still have +12VDC in the bilge - wired direct from the battery even!

To my reading of Maine's ABYC E-11 posted above, this system complies. If that's the best you can come up with, with no requirement for positive isolation and protection, I'm sure glad we don't mandate ABYC standards over here!!

[mitiempo]

The only difference between that switch and the Rule switches that are so common in North America is the fuse in the negative. The switch is wired the same as the rule but with the positive coming from the battery through the fuse.

[Hartley18]

Originally Posted by mitiempo

The only difference between that switch and the Rule switches that are so common in North America is the fuse in the negative. The switch is wired the same as the rule but with the positive coming from the battery through the fuse.

Yep.. and I'm not sure why - but there must be a reason, because they could have saved some copper if they hadn't done it this way.

These things are used all over the world (mostly because they're cheaper than the Rule version!).

[mitiempo]

I've never seen one. But many are confused when hooking the Rule switch up and this switch could certainly confuse the issue!

It would be easy to change - lose the negative and run positive to the fuse and out to the center connection on the switch. The Rule switch needs negative for the light but this switch doesn't appear to have one. The bilge pump negative can go to a negative bus.

How expensive are they?

[Hartley18]

PossumMarine Inc in Florida sell the one I posted for US$13 - so it must comply with American standards. The one I've got is A$16 from Whitworths - pretty much the same.

Possum Marine, Inc.. Bilge Pump Switch, 3 Way W/ 10amp Breaker - Seasense 50010320

They do need a negative for the lights and re-wiring it would be a pain in the butt. Since it works ok the way it is, I'd be reluctant to modify it without knowing why they made it just they way they did. ...and that would be my argument with any Surveyor idiotic enough to flag it as an issue.

After all, it isn't like I don't have anything else to do...

[mitiempo]

Hartley

I didn't see the lights.

There are no standards to my knowledge except ABYC. There are many non ABYC approvet items available but for a builder to say his product meets their standards ABYC approved items would have to be used. It is less expensive though.

[peikenberry]

A lot of marine electrical equipment is being imported for China and Southeast Asia that looks just like stuff made here but that does not meet any US or ISO standards. A few years back the market was flooded with 3 way battery switches that looked just like Perko battery switches, but had a nasty habit of melting from high current.

Hartley, Actually you do mandate ABYC standards down under, they are just published as Australian. see :: National Marine Safety Committee ::: :: But they were borrowed form ABYC and ISO.

Just because something is sold in the US as "marine" it doesn't mean it meets any US standards, because ABYC, and UL standards are voluntary. There is plenty of stuff like this on the market that doesn't meet any US or international standard.