Electrical connections to mast problem

[FairweatherDave]

Hi.
Basically I have just had the mast stepped on my (new to me) Centaur and I am trying to reconnect the electrics.

One cable is a mystery, which is the middle black one coming up into the box with a standard blue, brown and earth. I know these 3 connect to the three connectors available on the left hand end of the block (which have a black, red and brown going back to the bowels of the boat). (You need to ignore the black cable above the connection block on the left hand end as it is a photographic illusion and does not connect inside the junction box).I am guessing the black is an earth ( it is a fatter wire) and the red and brown go to the brown and blue. Am I right? An informed guess from people here would be most appreciated. The other two photos in my public album on my profile show the switch panel front and back. (Apologies for my clumsy photo attaching).
Thanks for your help anyone.
Dave

PS There are four cables that come from the mast, a VHF aerial, a wind "instrument", a mast head nav light and an unknown one. A guess on the function of the fourth would be a bonus.

PS2 The photo may need to be moderated before it becomes visible or you may need to be logged in to view it.

 

[FairweatherDave]

Apologies for a crude "bump" but I'd love help with this. You do need to be logged in and then you can see the piks. Ta anyone
Dave

 

[VicMallows]

Rather than hoping that anyone may be able to tell you to 'connect this wire to that wire' I suggest you need to get hold of a basic multimeter and start learning how to work out which circuit is which. Plenty of help available here. By now the wiring on your particular boat is likely to be totally unique.

 

[pvb]

Apologies for a crude "bump" but I'd love help with this. You do need to be logged in and then you can see the piks. Ta anyone
Dave

Your album apparently has no pictures in it. You need to sort this if you would like help.

 

[capetown]

Dave,
I can't see your photos yet.

Could the three core cable be, supply for combined steaming/deck light or have you a mast top nav light?

I think you would be correct in assuming that black is 0v.

If you have a multimeter you could connect it to the terminal block and operate the most likely switch/s. Also determining which is +v and 0v.

If you can connect a temporary supply to the cables going up the mast so that you can discover what wire lights what up.

You might have to wait till dusk to see what mast top lights are on, I can never see our mast top light in the day.

 

[FairweatherDave]

Thanks for all the replies. http://www.ybw.com/forums/picture.php?albumid=774&pictureid=4119

If you can see neither the photo in this reply nor in my album then we await the moderator for the piks. Apologies for now.

However re. the multimeter I have got one I inherited and I have tried to use it previously following idiots guide type instuctions off the web that allege it to be easy to use. It probably is but I haven't cracked it yet. I was hoping this might be a quicker solution.

The reason I was guessing the black is earth is because it is thicker than the other two which leaves guessing which of the red and the brown is the live one and which the neutral. This also makes sense as the rear of the switch panel is all connected in red and brown. Thanks for input Capetown, I will have an experiment next time I'm at the boat. The switch panel does mention a deck flood so that is the likely answer.

 

[William_H]

Mast wiring

You mentioned "neutral" in the last post. Neutral is a concept used only in 240v AC house wiring nto in boat wiring. So you need just a 12v power +ve and a return which you may call earth or -ve.
It is convenient as has been done to use house wiring flex that comes in 3 wires. The old system being green for earth black for neutral and red for live or power. The more recent system uses yellow/green striped for earth blue for neutral and brown for power. Now none of this matters to you. Any wire can be used for any job. 3 wires would generally indicate that you have 2 different lights on the mast.
As said these may be mast head nav light tricolour and or a white steaming light facing forward and or an anchor light shining white all round.
If you find a multi meter confusing then try a small 12v lamp on wires and a small 12v battery which can be connected to things. Use the lamp to find which wires from the cabin have power on them when various switches hopefully labelled are turned on. Use the battery to apply 12v to the various wires going up the mast to see which lamps operate when power is applied. Of course the lamps may be dead so you get no result. That my then require a trip up the mast or remove the mast again. Note here if LED lights are used they will be sensitive to correct polarity. Use your multimeter to find +ve and -ve.

Or do as I do and avoid mast lights all together relying on cabin side nav lights and stern light. And simply being illegal if I ever need to motor in the dark. And have an anchor light that can be hauled up a halyard and use this for motoring. good luck olewill

 

[FairweatherDave]

Cheers Olewill
That's really helpful re. the "earth".
As it happens I have the same philosophy re. boat nav lights, largely because I don't intend to sail at night. So I have a proper anchor light that goes direct off the battery and a Navisafe AAA battery LED nav light that fits on the pulpit (and I also have something rather fine and homemade LED inspired by one of your old posts for the stern if required).
Dave
Equally I look forward to sorting the original post problem out at leisure, (and in the dark) the priority is to get sailing at last on the new boat (its bleeding June now)!

 

[DaveS]

Well, it's a week since your last post but since you say you're not in an immediate hurry to sort out your mast electrics I thought a reply might still be useful.

Your link gives a black screen, not a picture. The text says that the image is 1 X 1 pixel, so that may be a clue that something is wrong.

I concur entirely with Vicmallows, and would go further: you cannot safely assume anything based solely on wire colours. Some of my boat's original 2 core wiring is blue and black with black being +ve!

Using a multimeter is in principle not difficult, but can sometimes be physically a bit fiddly. I keep on board a number of lengths of wire with sleeved crocodile clips at each end which allow me to connect up the meter probes leaving my hands free to do something else, like operating a switch. Maplin is one source of these, they come in packets of 10 IIRC and they're cheap, but I've found that some of them as bought do not work due to a crimp being over insulation and not making contact with the wire core. So first test each one by setting your meter to its lowest ohms range and clipping one croc. clip to each probe. You want to see a low value, ideally well under 1 ohm, which should be the same for each wire. When taking subsequent low resistance measurements subtract this value from each reading to get true resistance. Put aside any lead where the meter stays at 1 for later investigation / repair.

Now you can start investigating. Taking your three wire cable as an example, let's assume that it supplies a combined steaming light and deck floodlight unit. With a bit of luck you will have a labelled switch panel and can identify the relevant switches. It is normal practice for all switches to operate on the +ve side of the battery so we'll assume that is the case for now. With the battery main switch on, switch on the steaming light and set all other switches on the panel to off. Now set the multimeter to the 20V range and touch terminal 1 of the 3 way connector with one probe and terminal 2 with the other. If the meter reads something like 12.5 then you're lucky and seem to have hit on the right terminals first go. Confirm, however, by switching the steaming light off and checking that the meter now reads below 1V. If the meter reads - 12.5 when the switch is on then you've got the right terminals but wrong polarity. Swap the meter leads and it should now read 12.5 You have now identified the + and - terminals supplying the steaming light, so mark them.

If your first try did not find voltage, put one probe on terminal 1 and one on terminal 3. If that gives a reading, proceed as above, if not test between terminals 2 and 3. If none of these three tests show voltage then either there's another problem (is there an open circuit fuse or breaker? Are you sure the main switch is on?) or the initial assumption that the 3 way connector is for the 3 core cable is incorrect. If the latter, then further probing, testing every combination of pairs of terminals in the box will eventually reveal the steaming light + terminal.

With the steaming light switch on, leave the +ve meter lead connected to the steaming light + terminal and touch each of the other terminals in the box with the -ve lead. Some of these should also show voltage: these are also -ve terminals and can be so marked. Now switch off the steaming light and switch on the deck flood, place the -ve meter terminal on one of the - terminals and probe the other terminals with the the +ve lead. One, and only one, should show voltage: this is the deck flood + terminal: mark it.

So now we have, hopefully all in the 3 way connector, identified and marked the + terminals for the steaming light and deck flood and their common - terminal. Now for the cable: the fact that one core is thicker than the others makes it likely that this is the common - wire, but trust nothing! Set the multimeter to the lowest ohms range and connect one lead to the thick wire. Now probe each of the others in turn, noting the (corrected) resistance for each. Let's say you get 1.1 and 0.4 ohms. Now test between the two thinner wires: if the result is about 1.5 ohms then you've confirmed that the thick wire is the common - return. The wire that showed the lower resistance is connected to the higher wattage lamp - probably the deck flood - so now you know where to connect each wire. Labelling everything now will make the job faster next time. If measuring resistance between any pair of wires shows an open circuit (meter stays at 1) then you've either got a blown bulb or a bad connection somewhere aloft. Techniques for ascending masts are another topic ...

 

[VicS]

Apologies for a crude "bump" but I'd love help with this. You do need to be logged in and then you can see the piks. Ta anyone
Dave

If you are trying to use the Albums to post pictures you have to inform admin by email that you have pictures awaiting moderation.

Best to forget the albums .. They are next to useless .. at least they are the way they are operated.

Use the "attachment" method ... details of how to are in the FAQs

Better by far is to set yourself up with a free Photobucket account and use that.
Unlimited capacity and you can use the pictures you have stored there for all sorts of other purposes not just for these forums

 

[FairweatherDave]

Wow! What can I say..... thanks DaveS for taking the trouble. I'll be printing that out for another crack at it when I have time on the boat as it is a good project to learn to use my multimeter. As usual time is the issue but hopefully I will update you within a month (the priority is floating caravan time with the family and fortunately I have good lights I can use as required, mainly the anchor one.... I'll run that off battery 2).
Thanks on the photo advice Vic, I thought they would moderate after the long BH weekend, the whole system is a bit weird.