Product Description

Key Switch – Ignition / Overboard Discharge

Quite a nice key switch from Cole Hersee.  This switch is commonly used as either an engine ignition/start switch or can be used as an overboard discharge lockout switch.  Both functions detailed below.

It’s got a very nice matte black appearance.  Strong thermoplastic construction, and boasts a fully sealed contact area with O-rings and ultrasonic welding.

It is supplied with two matching keys with a nice looking black boot.

The switch is waterproof to IP67 for ingress protection when connector is installed on rear.

The contacts of this switch are rated at 10A at 12Vdc nominal, and 5A at 24Vdc nominal.

We love that this switch comes integrated with a Deutsch compatible 6 pin connector.  Mating AT06-6S connector sold separately here.  It makes a nice sealed connection, but you WILL need this connector to use the switch.

The function of this switch is OFF-ON-(ON).  Just like your car ignition switch is… where the single input is sent to a latching function at about 1 o-clock, and there’s a momentary (start) function at about 2 0-clock.

Key Switch Pinouts:

1. Battery Input
2. Start (the momentary function at 2 o-clock)
3. Acc (not used on this variation)
4. Ignition (the latching function at 1 o-clock)
5. Ignition (a second output of pin 4, connected internally)
6. Battery (a second input of pin 1, connected internally)

Complete Spec Sheet here

Dimensional Drawing here

When Used as an Ignition Switch

As an ignition switch it’s pretty straight forward.  Power input from your fuse comes into pin 1.  Your “accessory” loads, like engine electronics, and usually your dash instrument power gets attached to pin 3.  And your starter relay coil positive is attached to pin 4.

When Used as an Overboard Discharge Lockout

So there is a Coast Guard requirement to lock out your blackwater tank from overboard discharging except for offshore use.  This can be satisfied with a pad-lockable ballvalve, or an electrical lockout like this switch.

This key switch can be used for this purpose as either a latching switch or momentary depending on which output terminal (3 or 4) you tie the pump to.  It might be better to be momentary if you run the pump directly to the switch.  Or, say if you have another helm switch you want to use, you could wire it in series with the helm switch using the pin 3 latching connection, so that when you are offshore and turn the key to the ACC function, then your helm based rocker switch will work.

Turn it off again, and remove the key and it satisfies the Coast Guard requirement to have a key locked overboard blackwater discharge.

Your macerator pump pull more than 10A?  No problem, run it through a relay like this one.