Matching pairs0.

All U Get

All U Get

.
Oct 2, 2008
3,811
Pearson/ 530 Strafford, NH
Hi all,
I'm installing a two pole changeover switch to my 12V anchor light and have been trying to find the mating pair of wires in my panel. While holding my test leads on the pair at the base of the mast I get 13V with the breaker on, 0.V when it's off. Good. So if I disconnect the return line (aka, black, negative, ground) from the panel buss bar, I should get 0.V with breaker on or off? With three columns of DC breakers I've already tried the 10 closest to the anchor light breaker with no success. I'm thinking there must be an easier way.

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woodster

woodster

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Sep 15, 2009
6,244
S2 9.2a Fairhope Al
are you hunting the black wire to the light...let me restate that question ...are you trying to find the black (return) wire between the light and the buss bar
 
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Ron20324

Ron20324

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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
IIRC my work days.... If your leads are still on the switch, with the black wire removed, the lead on the pos will read that. The other, black, lead is reading the resistance- reduced volage. The light's resistance- in effect- makes a voltage drop that you may be asking about?
 
Davidasailor26

Davidasailor26

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May 17, 2004
6,150
Beneteau Oceanis 37 Havre de Grace
I wonder if it's possible that the ground from the light is connected or shorted to some other ground, like the mast itself. If that were the case then disconnecting the ground from the bus would have no effect.
 
All U Get

All U Get

.
Oct 2, 2008
3,811
Pearson/ 530 Strafford, NH
woodster said:
are you hunting the black wire to the light...let me restate that question ...are you trying to find the black (return) wire between the light and the buss bar
Click to expand
Yes, I would like to wire it to the changeover switch. Up for anchor, down for Tricolor. It's a LED from NASA. Here's the choice of wires less the ten I tried.

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woodster

woodster

.
Sep 15, 2009
6,244
S2 9.2a Fairhope Al
have you found the 12v wire coming from the panel breaker and does that act as a switch to turn on the anchor light at this time....as for the black wire hook up a wire on the deck connection and run it back to where you are working on the panel 12v - buss and take your ohms meter ...hook one side to the temporary wire you ran from the deck connection and keep probing all the black wires till you get a reading and that will be your 12v black to the light...you will have to probe the wire not the connection/terminal on the buss
 
woodster

woodster

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Sep 15, 2009
6,244
S2 9.2a Fairhope Al
if you prob only the buss connection you will get a reading no matter where you prob you want a reading of the wire not the buss
 
All U Get

All U Get

.
Oct 2, 2008
3,811
Pearson/ 530 Strafford, NH
Yes I know which breaker runs the light. So in the panel I have to disconnect each black wire one at a time and check for resistance?

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woodster

woodster

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Sep 15, 2009
6,244
S2 9.2a Fairhope Al
from looking at your panel i think i may have to come up there and stand on the deck and you unhook each black wire with the light burning until i say it went out.... stop hunting....just let me know...
 
capta

capta

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Jun 4, 2009
5,072
Pearson 530 Admiralty Bay, Bequia SVG
You have 3 wires at a new masthead fitting? An anchor light, a tricolor and a common ground?
You have an on/off on the panel? So you need another positive wire to activate one system? Unless (like us) you have several wires running to defunct masthead systems (strobe, etc) I think you will have to run a third wire.
Way off topic, but if you don't already have a tricolor, I wouldn't put one on.
Having spend a portion of my career on the bridge of ships 50 or more feet up there, that disembodied light waving around in the dark is way less visible to me (remember I'm looking DOWN at a sailboat) than the red, green or white light shining on a bit of water around the bow or stern. IMO they are one of the most dangerous bits of relatively new tech out there.
 
heritage

heritage

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Apr 22, 2011
974
Hunter 27 Pecan Grove, Oriental, NC
Ron20324 said:
Just wondering why you have to I.D. the black wire???
Click to expand
That's what I was also wondering. If the old anchor light is working, then you know that it is somehow connected to the negative side of the battery,,, probably to a DC negative bus somewhere. Normally, switching is done on the POS side of the anchor light. No reason to be concerned about the black wire that I can see.
 
All U Get

All U Get

.
Oct 2, 2008
3,811
Pearson/ 530 Strafford, NH
Red and black run from panel to anchor light for the circuit. When red is positive the anchor light is white. Now flip the switch and the black is now positive and it's now a tricolor. Two wires, two colors, one light that's 4" tall instead of a 10" Aquasignal.

Finding the black partner in the panel would make it convenient. Do they make sound resonator for tracing DC wires?

http://www.nasamarine.com/product/supernova-combi-tri-and-anchor-l-e-d-mastlight/

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D

dlochner

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Jan 11, 2014
14,007
Sabre 362 113 Fair Haven, NY
It may be much easier to simply run a new wire. Alternatively mount the change over switch near the mast and the known good black wire. If you choose the new wire option, be sure to label it.
 
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Ron20324

Ron20324

.
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
[QUOTE="...Red and black run from panel to anchor light for the circuit. When red is positive the anchor light is white. Now flip the switch and the black is now positive and it's now a tricolor. Two wires, two colors, one light that's 4" tall instead of a 10" Aquasignal. Finding the black partner in the panel would make it convenient. Do they make sound resonator for tracing DC wires? ...All U Get[/QUOTE]

I believe Home Depot still has a wire tracer. Are you sure each wire does not have a number stamped on it to match the wiring shematic, like Benny does? But isn't the reversal done at the switch, or maybe you want to put the reversing switch at the breaker panel?
 
All U Get

All U Get

.
Oct 2, 2008
3,811
Pearson/ 530 Strafford, NH
dlochner said:
It may be much easier to simply run a new wire. Alternatively mount the change over switch near the mast and the known good black wire. If you choose the new wire option, be sure to label it.
Click to expand
New wire may be the only way. Hate leaving unused wires behind since I have a few already left by others.

The schematic has numbers for the big systems, but not the DC for lights and fans. I'll give my clamp meter a shot before I drive to HD.

(or maybe you want to put the reversing switch at the breaker panel?). Yes

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Head Sail

Head Sail

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Nov 13, 2013
723
Catalina 34 Tacoma
Why don't you turn the light on and disconnect each black. When the light goes out you e found your wire.
 
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woodster

woodster

.
Sep 15, 2009
6,244
S2 9.2a Fairhope Al
is there any danger of that black wire sharing its purpose with something else like a branch of some sort
 
All U Get

All U Get

.
Oct 2, 2008
3,811
Pearson/ 530 Strafford, NH
woodster said:
is there any danger of that black wire sharing its purpose with something else like a branch of some sort
Click to expand
Yes, but from the mast there are three black wires for the different lights. I followed the bundle under the settee then lost them as they entered a chase. The bundle near the end of the chase combines every wire forward of the panel which is quite a few.

I checked out wire tracers and for DC they're not cheap. I asked the local think tank and got referred to MIT. I'll try pulling the black wires at the panel again, only 20 left I haven't tried.

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