1-2-B Switch and Wring
Hi, Bob,
Oh, boy! The 1-2-B switch: my favorite subject!
1. Don't worry about the positions of the posts behind the switch. Phil's right.
2. If YOU want the house bank to be #1, go for it. In fact, if you ever add a Link 2000, the house bank will HAVE to be #1. A "...normal" for choosing #1 or #2 simply does NOT exist.
3. Use the "C" - common post to run two things, and two things only: the power to the distribution panel (DP) and wire to the starter (unless your alternator output is there, too, see #4 below). Do NOT run your DP from the #1 post because when you turn off the switch, stuff will still be ON.
4. Alternator output & choices: While not mentioned, and perhaps previously discussed with you here on this 'board
http://forums.catalina.sailboatowners.com/showthread.php?t=107109, your alternator output should run directly to your house bank, and NOT to the "C" post of the switch. You'll need a means of charging your reserve bank with an echo charger, relay, combiner, or a simple on/off switch - your choice. If you still run your alternator output to the "C" post of the switch, know that your switch will then determine which battery gets charged when the engine is running, as well as which battery is being used for power when the engine is off. If wired with the alternator output to the C post, do NOT move that switch, ever, when the engine is running, please. Your boat, your alternator, your choice.
Alt. Output Choice: IF the alternator output now goes to the "C" post of switch, you could, very simply, just move your alternator output from there to the #1 (house bank) post of the switch - it's simpler than completely rewiring the alternator output to the house bank if you don't have the time or want to bother, and is electrically exactly the same: think about it to understand this simple idea that I used for many years before I installed our high output alternator and rewired directly from the alt. to the house bank.
This only works if you have TWO separate wires from your C post: one to the alternator and the other to the starter. But check the wire size from the switch to the bank to make sure it's adequate; it's usually #4 wire on Catalinas, so if you still have the OEM alternator, it should be just fine. If and when you get a high output alternator, then you can and will need to change the alternator output directly to the house bank because the #4 wire will be too small for the current it needs to carry over that distance. If you do this simple change now, you'll still need "a means of charging your reserve bank with an echo charger, relay, combiner, or a simple on/off switch - your choice."
I highly recommend this simple change, highly, get it? Get the danged alternator output OFF of the C post and you'll sleep a lot better, knowing your switch cannot ever harm to the alternator EVEN IF YOU TURN THE SWITCH TO OFF WHEN THE ENGINE IS RUNNING!!! That's because the alternator output always has a route to the house bank. It's easy to do, and in most cases the wire from the alternator (unfortunately) is already there - just move it from the wrong C post (which boat factories continue to do!!!) to the right (house bank) post.
5. "
As it is currently wired, there are 3 additional 8awg wires directly to both posts attached to different circuit breakers." YOU have to trace these down and find out what they are serving. What does "both posts" mean, since you have three posts???
Remember: There are three posts on the switch, there are four positions.
#1 house bank output to #1 on the switch. #2 reserve bank output to #2 on the switch. DP and starter to "C" on the switch. "Always on" loads, like the bilge pump and stereo memory wires can go either direct to the house bank or to the #1 post on the switch (which is probably what some of those three "extra" wires are from).
Draw a wring diagram, for both before and after.
Again, you may have this already, but here's a link to my wiring diagram, see reply #23, here:
http://c34.org/bbs/index.php/topic,4623.15.html
A picture is totally unnecessary. Have fun!
PS - Bob, thanks for bringing this up. You're last post stirred me to document the wiring diagram changes, and this one resulted in a new topic on our C34 message board, here:
http://c34.org/bbs/index.php/topic,4934.0.html
