What type of switch do I need?

[slug]

Originally Posted by mikedefieslife

Now only to find it in rocker form or push button. Ideally rated up to 20a to eliminate the need for relays.

The manufacturer one is by Carling Technologies, but I couldn't see it in their catalogue.

I haven’t looked at the catalogue, but Blue Sea system has a good selection of push button switches suitable for the marine environment

These are commonly available at marine stores Perhaps high amps rated



If you have access to a professional supply house Such as Grainger ..they have a vast selection of switches ...

https://www.grainger.com/category/el...nd-accessories

[Cadence]

If it is going to operate the macerator as one function make sure it has a sufficient amp. rating.

[smac999]

Draw a diagram. I still can’t Understand what you are asking. Are you trying to join 3 wires in the middle. (6 ends)? 3 in and 3 out. Each separately connected As 3 circuits. Or actually joining 3 wires into Single joint. It still seems you are trying to join a neg to pos which makes no sense. As opposed to completely 3 separate cicuits with a single switch.

[Dsanduril]

Here’s a link to DPST switches that should be filtered to 20/25A DC:

https://www.digikey.com/products/en/...=1&pageSize=25

And here’s a Carling rocker from in that list:

https://www.digikey.com/product-deta...274-ND/3025054

Rated 20A at 12VDC, $12.46.

Here’s the same switch in momentary (spring-loaded, you have to hold it to keep the contacts):

https://www.digikey.com/product-deta...275-ND/3025057

I’m not a huge fan of the spade connectors on the Carlings, but on the plus side they are IP67, fully sealed, water”proof”.

[john2445]

Positive and negative have to be on opposite sides of the device or nothing happens. I think what you are calling the negative is actually the positive from the power source and you just want to switch it to the positive of 2 devices.

I don't know why the 2 positive wires to the devices shouldn't be connected. Actually, they will be when the switch is on. If they really shouldn't when the switch is open, then the double pole single throw is necessary. Otherwise a simple momentary switch is all you need.

But I could be wrong.

[oleman]

Originally Posted by lorenzoj

A three pole single throw switch will perform this function, if the terminals ou the output poles are shorted together. A 3pst switch is what You need.

Right on: the poles of a switch are isolated inputs and outputs but all poles are switched at the same time.

You need to locate a technical manual on switch terminology. Cole Hersey is a good place to start. They also have a good range of power type switches, Carling is an electronics switch company and they have a vast array of pole combinations available.

[Dsanduril]

The OP has three wires. The absolute most he needs to isolate them and combine them is a two-pole switch. A three pole switch would have all the wires land on one side, then what? Jumper all the poles on the other side? That’s an inefficient use of poles and means that everything goes through two sets of contacts.

[FlightPlan]

I think he wants a momentary switch. Where the two positives complete the circuit when the switch is pressed and broken when the switch is released.

[skipmac]

OK, problem is just one of terminology. From further explanation Mike wants to put a switch in the positive line feeding his macerator. FYI, Mike the negative is on the other side of the pump going back to the battery or boat ground.

The other question, it sounds like there are two functions you need to accomplish. Connecting two positive wires will only jump their power together. To activate two functions you need to connect to two different output lines, what you originally called negatives. The way a circuit works, power (positive) goes to a device (like a pump), through the pump to make it work, then out of the pump back to the battery or ground.

If you are connecting two positives to one wire that wire will be going I assume to only one device, either the pump or the valve. Assuming this will not cause some mechanical problem or other what you need to do is connect one positive to two different wires (what you called negative), each wire going to a different device. Then when you push the button or turn on the switch you send power to both things and they both work at the same time.

This also assumes the one positive wire you connect can supply enough power to run both things.

[Cadence]

Originally Posted by FlightPlan

I think he wants a momentary switch. Where the two positives complete the circuit when the switch is pressed and broken when the switch is released.

I believe you're right. Keep guests from over using a flush.

[Dsanduril]

A picture being worse a thousand words....

OP, is this what you are trying to do?



This is a DPST with a jumper on one side. The dashed line indicates that the two switches operate together.

Still don't see why post #5 (combine the macerator and water wires together) with a SPST won't work, but if you want to keep them separate the DPST will do the job.

[Mark Thurlow]

Try this- all the functions
See attachments

[Mikado]

This is the momentary switch my toilets use.

https://www.amazon.com/dp/B00K59X1D4..._LVIlEbFV855JG

[SeaBreeze-1]

After reading through most of this thread, I think I understand what you are trying to do:

You have power coming separately, into a pump and a macerator and they each have "output" wires that you want to combine through a single switch so that both items are activated when you push a button. Simply join the two output wires together before they are connected to a momentary SPST switch (with the required amperage rating to fit the job).

I'm not certain what ABYC standards have to say about this, but typically, you would combine wires by using a small buss bar before connecting to the switch. This makes for a nice, securable connection point for the wires. A single wire is then run from the buss to the switch and this is then connected to the negative that returns to the batteries. There are different ways of soldering the whole thing together but if assembled properly with ring and knife connectors, you'll find it a whole lot neater and easier to maintain when the need arrises.

[Cadence]

I have a feeling he wants to keep them separate so that the macerator can be activated independently through another switch, possible discharging his holding tank.