reverse polarity

[dhagen]

Today I replaced a 12V ciruit breaker to my anchor light on my 2001 Catalina 34.  I did not remove any wires from the AC side of the panel.  However, after going sailing and reconnectilng my shore power, the AC said I had reverse polarity.  Anybody have any idea what would cause it and how to fix it?  Everything on the DC side of the panel seems to work fine.
Thanks,
Dan Hagen

[Ron Hill]

Dan : Are you sure that you replaced a circuit breaker? or a switch to the anchor light? 
The DC side of the main panel should have nothing to do with the AC side and reverse polarity, unless somethings from the AC side may be touching and giving a reverse polarity signal.  If AC touches any DC I'd guess that the breaker would trip!?! 
Could you have misaligned the shore power plug when plugging in?

[dhagen]

I replaced breaker on the panel that shows its for the anchor light.  I guess it is also the switch.  It is what you flip to turn on the anchor light.  I don't think I misaligned the plug, because I also tried my next door neighbor's plug to make sure it wasn't my electrical box or cord.  When I press the little rocker switch for polarity, it lights up as reverse polarity and if I just try to turn on the main AC breaker it makes a noise and I didn't try to press the issue.  There is also switch on the back side of where the cord goes into the boat under the seat.  I was working on the steering cables.  If that had gotten moved, would that have done anything?  I can't figure out what happened.
Dan

[Mike and Joanne Stimmler]

Dan, I would start with checking the polarity out of the electric panel at the dock. It wouldn't be the first time that something coincidentally got changed on something other than what you were working on.
My MK1 doesn't have a switch under the seat as you describe. If this isn't something common to MK2's you may want to look into that switch. If it is something added by the PO, who knows, it could be another breaker, a shut off switch or even a polarity reversing switch.
Double check all the areas where you have worked on things to make sure there's nothing obvious that you've disturbed.
If your not comfortable with working with electricity then you need to involve a marine electrician. You definitely don't want to take chances on this.

Good luck,
Mike

[Stu Jackson]

There have been a number of discussions about reverse polarity.  A search finds these:

http://c34.org/bbs/index.php?topic=3761.0  Reply No. 1 has a link to another thread with further discussion.

You may want to try more searches (on polarity and reverse polarity) to find out more, although most are about generator use and polarity.

One of the keys is to use a simple Ace Hardware portable polarity tester, since low dockside power sometimes fools built-in polarity indicators.

[tonywright]

You said "When I press the little rocker switch for polarity, it lights up as reverse polarity..."  Are you sure the little rocker switch isn't just a test to see if the light bulb is broken? If it is, it would light up every time you turn it on if AC power is connected.

If this is the case, the noise from the breaker could be that you have some kind of load or short cicuit that it is trying to protect you against. Maybe a piece of wire or a screw fell into the AC side while you were working?

Tony

[Craig Illman]

Dan - I'd have to agree with Tony, it sounds like something is touching on the AC side that shouldn't be. Do you have a multimeter to check the polarity on the AC without turning on the main breaker? I finally decided that a small multimeter is another necessity for the onboard toolset.

Craig

[Wayne]

"Little switch on the back opposite where the cord plugs into the boat"
I have a MKII; that switch you describe is the 'master' 110 breaker for the boat; I manage to trip it most every time I retrieve something bulky from that locker.  I'm guessing you have a MKII?  Could you have jammed something against the mechanism of that switch when you were working on the steering?

[tonywright]

You could be on to something, Wayne!

Tony

[dhagen]

I don't think I hit the switch under the cockpit, but I will check.  I have a multimeter.  How do I check the polarity and where?  I'll also check and see if there is a loose wire or screw somewhere, but I already did that, or at least thought I did.  And yes I do have a MK II.
Dan

[Craig Illman]

Dan - Checking polarity. You should have a black (hot), white (neutral) and green (ground) coming to the AC side of the panel. Reverse polarity implies that there's 120V between the white & green, instead of the white and black. Black to white should be 120V, black to green could/should be 120V (probably depending on whether your boat has galvanic isolation), but white to green should be zero volts.

The GFI should trip if it sees any current on the green leg or possibly less current on the white leg than black leg.

Please, anyone correct me if I've confused anything.

[Mike and Joanne Stimmler]

Guys,
A little clarification.
If you have a reverse polarity, you will still have 120v between the black(hot) and white(neutral).
You need to use the green as the ground reference point and confirm that you have 120v between the green and black and 0v between the green and white.
If you have 120v between the green and the white, then you have a reversal!

Mike

[dhagen]

I talked to Catalina today.  The polarity rocker switch is only to check the light bulb.  If it is not lit, which it is not, then I don't have reverse polarity.  I will check the box to see what else may be wrong.  I appreciate all the help.
Dan Hagen

[Ron Hill]

Dan : Interesting!! 
It's been my experience that "test" switches are/should be momentary or spring loaded!!  This means that when you engage the "press to test" switch the light would come ON and when you take your finger off the switch it should go to the OFF position - automatically. 
If Catalina didn't do that - then shame on them!!!  A thought

[dhagen]

No, that is what happens.  When I press the rocker switch the light comes on.  When I let go it goes off.  They did it right.
Dan