Oct 16, 2006 04:31 pm
Re: 3 way switch
Hi Bruce - it doesn't matter if the power is AC or DC, the wiring of a 3-way circuit is the same. I'm guessing you've checked and double checked your wiring to the diagram you are using (I don't know, but perhaps the book has it wrong). If you post an email address I can send you a wiring diagram to try. I would caution you that using inexpensive, readily available 3-way switches commonly used in the AC world could be a problem. They typically aren't rated for DC use. To be safe, I would recommend using a commercial grade switch and limit (by limiting the number of lamps and their current rating) the switching to a couple of amps. The problem is that arcing in switches (happens in all of them), particularly when breaking contact, is typically quenched as the voltage passes through zero (in the AC cycle). In a DC circuit, this doesn't happen. Generally this means that the life of the switch will be shortened vs. AC use. In extreme cases, it could be a fire hazard. So limit the DC current you are trying to switch to well below the rating of the switch. Anyway, let me know if I can help you with your wiring circuit problem.
Regards -
Tom Hardy, PE
HVTA, Inc.