# spst illuminated switch?



## idivein (Mar 13, 2013)

how to wire illuminated rocker switch. lite is neon. i have mrc dcc to rails. there are 3 lugs to attach wire on switch. used meter to determine which 2 to wire(2 silver). no lite but works for power. third lug is gold? what do i hook up to gold lug to make the lite work?


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## Bwells (Mar 30, 2014)

It sounds like you are missing a ground to complete the circuit for the bulb. I think DCC is 16 volts AC, is your switch for 12 volts?


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## idivein (Mar 13, 2013)

switch is for 125v. ground to where?


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## Brakeman Jake (Mar 8, 2009)

These switches just aren't DCC friendly...


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## idivein (Mar 13, 2013)

what lighted spst switch would work?


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## Ray Haddad (Feb 19, 2014)

The light is neon, you say? Well, the switch will be rated and most likely it will be for mains voltage with an appropriate resistor added for the neon bulb. Yes, there are other forms of illumination that need specific voltages to work. Neon is one of them. In order for it to ionize inside the little bulb, you need a very specific voltage.

Years ago we used to put them on amateur radio antennae. They'd light up when the transmit button was pressed. No resistor required for that use. The will absolutely not work on DC and the AC equivalent on DCC is just not enough juice.


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## DonR (Oct 18, 2012)

What is it that you want this switch to turn on and off?

The type of switches depends on the use.

Don


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## idivein (Mar 13, 2013)

service track feed off turntable. cut 1 wire and put spst switch in. lite to work when power on thru switch.


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## Ray Haddad (Feb 19, 2014)

idivein said:


> service track feed off turntable. cut 1 wire and put spst switch in. lite to work when power on thru switch.


What is the electrical rating on the switch?


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## idivein (Mar 13, 2013)

25a 12v dc with red led. 3 lugs to wire. i can wire 2 and switch works but lite doesn't. 3rd supoosed to be ground? ground from where?


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## Brakeman Jake (Mar 8, 2009)

no where...if you were flowing DC through your switch,you'd have a ground...with DCC you don't.


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## Ray Haddad (Feb 19, 2014)

idivein said:


> 25a 12v dc with red led. 3 lugs to wire. i can wire 2 and switch works but lite doesn't. 3rd supoosed to be ground? ground from where?


Then it's not a neon light but an LED. You may have your polarity wrong on the LED. Does it have a separate set of terminals for the LED?


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## Brakeman Jake (Mar 8, 2009)

I've installed quite a few of theses switches in trucks and other machineries to power auxiliary lighting and other low draw equipment.There's no mistery to them...they have an identified input and an output wich feeds whatever equipment AND the small bulb within the switch so that it glows when the accessory is "on".The third terminal is simply a ground for the bulb to work,having no effect on the switch itself.

Since the bulb is rated at 12 VDC,this is the rated voltage of the switch.You can use it for higher voltage but the bulb will burn right away.


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## Bwells (Mar 30, 2014)

Hold on here. The switch is incandescent and you are switching one half of the circuit. That is the way to turn off power to a dc track but you mentioned dcc. It is still the same but the voltage maybe different which is what I would be concerned about. In order for the bulb to light it requires the other half of the circuit. Power in on one end, power out on center tap, common in on other tap. When you turn on the switch it sends power to the rail as well as to the bulb but the bulb needs to see a ground, common, other half of the circuit in order for it to light.


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## DonR (Oct 18, 2012)

It does seem you guys have the right idea about the
switch that needs the other side of the DCC track current to
light the light. The main issue then is the voltage
to the bulb. How about a resistor and possibly
a diode on the 'ground' or common side of the track current. 
First it must be determined exactly what type of bulb is in the switch
and what voltage it can take. AC or DC? Then go from there.

Don


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## Brakeman Jake (Mar 8, 2009)

There's no doubt in my mind that this idea could be made to work fairly easy since a DC bulb will light with DCC but aren't we forgetting something here?Isn't DCC supposed to power our trains,not the layout fixtures?


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## idivein (Mar 13, 2013)

yes but this is not a fixture. it is a switch on an isolated section of track. thanks for all the input i have learned alot. it is so nice to have knowledgeable people in this hobby. where would we be without the brotherhood? thanks again.


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## Brakeman Jake (Mar 8, 2009)

Agreed the switch isn't a fixture...the bulb is though.


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## DonR (Oct 18, 2012)

I'm still curious. What kind of bulb is in the device?

Don


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## Brakeman Jake (Mar 8, 2009)

I've installed switches of this type as far as forty years ago so they obviously were incandescent then.It would make sense that they'd be LED's by now but can't tell.I checked a manufacturer (Cole Hersee) and their website doesn't say.


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## idivein (Mar 13, 2013)

the switch is 125vac with an led. does not specify the led details. i hooked the 3rd lug with wire from the tap off the other track wire. it the lite works! the switch is off most of the time. i checked the track voltage with switch on. it is 14.8vac. perfect.:appl:


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## Ray Haddad (Feb 19, 2014)

Just get a wall wart power supply and use it to light the light. Do not use the DCC voltage. That's just asking for problems.


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## Bwells (Mar 30, 2014)

Great to hear! Ray, you can't separate the bulb from the switched leg


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## Brakeman Jake (Mar 8, 2009)

The gentleman wants to interrupt current on sections of track and at the same time have a pilot lamp aknowledge when power is "on",so that he has to feed the switch with DCC.When in "closed" position,the switch flows the current from a single input terminal to both the output terminal and to the imbedded pilot lamp wich in turn needs a ground terminal to work.That is if I understand it right...

The switch can flow the DCC current through...no problem there.What bugs me though is the possible effect bridging DCC with one or more bulbs can have on the digital signal that's traveling along with the track current.As far as I know,the only devices that should bridge between DCC leads should be decoders.


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## Ray Haddad (Feb 19, 2014)

The switch can be transparent to the DCC but not the light. No matter what kind of light it is, it will negatively impact his DCC signal.


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## Bwells (Mar 30, 2014)

This should fix anything: DPST add a bulb and a power supply. Half the switch for DCC, the other half to work the light, separate voltage but a bigger footprint on the panel.


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## trains galore (Jul 22, 2013)

Interesting:stroke:
I agree with Ray, personally I wouldn't try powering the lamp with the dcc, it would be easier to just get some dpdt switches and 3 wire bi colour leds, you use one set of terminals for indicator lights, and the other half for the actual switch

If you are really set on having lighted rocker switches, then you could use a lighted 12v rocker to switch a small relay which controls the dcc signal, but it would end up costing more and more wiring too


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## Ray Haddad (Feb 19, 2014)

Behind your control panel, add a 12v bus for all of your switches - just for the lighted portion. The rest of the switch can then be used to control your trackage and accessories.

The DCC signal on the track is already a dog's breakfast. You would be so surprised that it ever works if you could see it on a scope. Adding any active component to that will affect the signal adversely. No matter how benign you believe it to be, there will be some effect.


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## Brakeman Jake (Mar 8, 2009)

Why not rely on the switch's lever position as an "on/off" telltale?....Come to think of it...too simple...not impressive.


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