2 way light switches with dimmer on a boat....help please

[yachtcaptain]

I've got 2 light switches operating the same light (2 way lighting)
Both swiches have dimmer functions
Having unwired both switches from the wall there are only 2 wires going into each one????

if you take the 2 wires touch them on each other for 1 sec light goes on/off
if you touch and hold light dimms

THERE IS NO 3rd wire??? How can this be???

Problem is i want to add an extra few lights onto the same circuit???

How can I go about this? I was going to add the wiring just before the switch.
But this dimmer situation has confused me!

Thanks for any help!!!

 

[bernardgreen]

The switches would appear to be remote controls for a dimmer module fitted elsewhere.

To add more lights you will need to find this module. With luck it will have a rating plate with details of the maximum load ( in watts ) it can handle.

Provided the total of lights does not exceed that maximum you should be able to wire extra lamps in parallel with the existing lamp.

The dimmer module may be part of the lamp.

 

[yachtcaptain]

Thanks for that reply.

Since my post I have wired an extra 2 lights in parallel which is just what you suggested. Everything works well. I didn't find the dimmer box but will have a look for it.
It is not in the lights as they are simple Halogen 12V20W models.

Would there be any danger not knowing the rating of the dimmer box and having wired in an extra 2 lights to the existing 4?

Also for my own interest and knowledge , I thought that 2 way switches had to have 3 wires going to them (one common)

But as stated in my previous post each switch has only 2 wires?

Does that mean that the dimmer box is doing all the work?
each switch would individually be wired to the dimmer box ?
where would the common be?
If you know what i mean.

Thanks again for your reply. I received it all the way in Spain
What internet does in this day and age !!!

 

[yachtcaptain]

Ok that may have been a stupid question, if i'm right:

12 V is supplied by a big battery bank

adding more lights to the system will never make the lights dimmer as the battery bank is very big.

more lights= more demand in Watts

and the dimmer box may only be rated for so many watts so therefore it could be dangerous and melt the dimmer box???

That is what I reckon. If someone could confirm i would be grateful!

 

[ban-all-sheds]

Eric's your man for boat electrics, but...

1) You can get multi-way dimmer systems which work as you described, and only have 2 wires to each switch - basically all the switches are in parallel, and connected to the control unit. A momentary contact from any switch toggles the lighting on/off, and a longer contact starts the dimming cycling up and down. Switches are either spring loaded or touch sensitive.

It would make sense for there to be a control unit when the entire installation is ELV as otherwise you'd need thumping great switches and lots of very thick cables all over the place. This way the switches and switch cables only carry a small control current.


2) This may be b****cks, but if it's a steel-hulled vessel is the hull used as a current path, like the body of a car is?

 

[bernardgreen]

Does that mean that the dimmer box is doing all the work?
each switch would individually be wired to the dimmer box ?
where would the common be?
If you know what i mean.

The dimmer box is doing all the work.

The dimmer almost certainly has a single control input for a push button.

Short pushes on the button change from ON to OFF ( of OFF to ON ) while a long push makes the dimmer change brightness in a cycle from Bright to Dim and back to Bright for as long as the button is pressed.

The two switches are almost certainly wired in parallel to each other and will appear as a single push button to the dimmer module. So only two wires would be needed.

Would there be any danger not knowing the rating of the dimmer box and having wired in an extra 2 lights to the existing 4?

There is a risk that the extra lamps will be overloading the dimmer. The danger is that the dimmer will fail or over heat. If the yacht is built to a high specification then the dimmer if overloaded will switch itself off before it becomes a fire risk due to over heating. But that is not a certainty. It may become hot enough to damage adjacent materials.

You may find the dimmer is fitted in or close to the main battery power distribution board

 

[yachtcaptain]

Thanks again guys. Both answers were very useful.
BAN ALL SHEDS, no the current is not running along the hull of the yacht. I think it would create issues with electrolysis !!! My opinion?
Besides the fact that salt water is a conductor so probably wouldn't work.

I have found all of the components to my lighting system and got it all worked out now. I think i'm going to have to swap out a transformer as the extra lighting is drawing too many amps.


I've got a transformer 230V to 12 V 105 W max. followed by remote control dimmer rated 1000W 230V
And I have basically added 2 x 12V20W lights to existing 4 lights that were there.

If i'm right :
1.6 A per light , so 9.6 amps are being drawn or 20W x 6 = 120 W

My transformer is rated 12 V 105 W max
So i'm 15 W over the rated capacity.

Remote dimmer is rated for 230V 1000W max.
FROM OHMS LAW THAT MEANS 4.3 A right? How would this work into the equation? Is 4.3 A the amount it is drawing? I'm just trying to make sure i don t have o replace the dimmer as well...?

From my understanding 230V supplies the dimmer, when requested 230V exits dimmer through transformer to 12V and on to the lights>

It would seem more logical o have a 12V dimmer but all i can see is 230V 1000W on my dimmer.

 

[Aragorn84]

The dimmer is fine.

Your transformer is overloaded though, so that will need replaced, and you'll need to ensure you get one that will work with the dimmer.

As for the hull, if its a battery driven system (like a car) then its quite normal for the frame to be connected to the battery negative.

Your boat seems to have mains power though, is this generated onboard?

 

[yachtcaptain]

Aragorn 84 ,

Yes the boat has got constant supply of 230V AC from 2 27KW gen sets.
But yes it is true that a 24/12 V system could work through the hull but not AC.

Yes I figured my transformer is overloaded.
But why is my remote control dimmer not overloaded as well ?

Actually the lights work at the moment but I guess one of the componens will burn out soon if I keep using it...

Also would the dimmer logically be supplied with 230V?

 

[Aragorn84]

dimmer will have 230v in and then 0-230v out depending on the amount its been dimmed by...

Dimmer is rated to 1000W, your only drawing 120w (plus some overhead for the transformer) so its nowhere near its limit.

 

[yachtcaptain]

I understand what I have to do but I sill don't get why:

Remote dimmer is rated for 230V 1000W max.
FROM OHMS LAW THAT MEANS 4.3 A right? How would this work into the equation? Is 4.3 A the amount it is drawing?

Otherwise all my issues are solved thanks guys!

 

[bongos]

I understand what I have to do but I sill don't get why:

Remote dimmer is rated for 230V 1000W max.
FROM OHMS LAW THAT MEANS 4.3 A right? How would this work into the equation? Is 4.3 A the amount it is drawing?

I would imagine the dimmer is drawing next to nothing. Certainly not 4.3A.

What its rating means is that it can be used on ciruits with voltages upto 230v.

It is rated to dim wattages upto 1000w. More than that and you need a dimmer with a higher rating.