I have to admit that electrical wiring is not my strong suit (by far) and since I am installing new lights, a new wind instrument and new coax for the VHF antenna on the mast for my winter re-fit project, I bought Dan Casey's Sailboat Electrics Simplified for guidance. A few things leave me with unanswered questions. I am planning on using a four-way plug connection to join the wiring at the mast base. I will have an anchor light drawing .83 amps (10 W) with a total round trip length from the terminal box to the top of the mast of 100', a steamer light, also .83 amps but the length is 65', and the deck light drawing 1.67 amps (20 W)with a length of 65'. Using the wire size formula for 3% voltage drop I find that the steamer and the anchor lights can be 16 guage and the deck light can be 14 guage. I assume that even though there is a break in the wiring where the deck plug is located (my mast is 33') I have calculated the round trip length as if the wire runs were continuous and independant. I thought about using primary wire to run positives up the mast to the lights and primary wire to daisy chain the negatives for the 3 lights down the mast. I reconsidered and figured I would rather use duplex safety wire because of the added insulation to the wire. I assume that for the 4-way plug to work, I would pigtail the 3 negatives into the plug and run one negative primary wire from the mast base to the terminal box. So to summarize the wiring, I will have 3 primary positive wires from the terminal box to the plug at the base of the mast, 3 duplex wires inside the mast serving the 3 lights, and one negative primary wire from the plug back to the box (about 15' one-way). So now, sizing the primary ground is my first question. If I assume the run is only 15', for 3.33 total amps it appears that a 16 guage wire is sufficient. That doesn't seem logical to me so I assumed that the formula should be used assuming the combined amps for the longest run of 100'. This leads me to a 10 guage wire. Is my logic faulty? I am assuming that ALL lights can be on at the same time (by mistake) even though it isn't logical for the anchor and the steamer to be on at the same time. Also, I thought I read that it is not a good idea to have a coax cable and an instrument cable in close proximity. I planned on putting them both inside the 1-1/4" pvc conduit that will be used to run all the wiring. Is this something that should be avoided? I figure that if the wind instument is disrupted during a vhf transmission it would be no big deal. Any comments about this?
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sounds correct to me
Scott Wire size you plan sounds right but not sure without checking voltage drop tables which it sounds like you already did. Coax is shielded cable and, with a properly tuned antenna, you should have no RF on the outside braid to interfere with any instrument wiring, regardless of how close they are.
Scott Wire size you plan sounds right but not sure without checking voltage drop tables which it sounds like you already did. Coax is shielded cable and, with a properly tuned antenna, you should have no RF on the outside braid to interfere with any instrument wiring, regardless of how close they are.
Scott...
If the 4 wire connector you are contemplating using is one of the small Perko-like screw-on plug units as found in the WM catalog, you might want to reconsider. I found the clearances extremely tight inside the plug for even 16 AWG wire, causing shorts when closed up. Consider a trailer wiring plug/socket assembly inside the mast to make for an easy mast removal the next time.
If the 4 wire connector you are contemplating using is one of the small Perko-like screw-on plug units as found in the WM catalog, you might want to reconsider. I found the clearances extremely tight inside the plug for even 16 AWG wire, causing shorts when closed up. Consider a trailer wiring plug/socket assembly inside the mast to make for an easy mast removal the next time.
Almost there
I'll concur that running coaxial next to power is fine; that's the beauty of the coaxial design, with the ground surrounding the signal. You need to account for 30' (15' X 2) on the final run to power and ground. Round-trip. Maybe 14AWG. But no need for 10AWG. Good luck. Paul
I'll concur that running coaxial next to power is fine; that's the beauty of the coaxial design, with the ground surrounding the signal. You need to account for 30' (15' X 2) on the final run to power and ground. Round-trip. Maybe 14AWG. But no need for 10AWG. Good luck. Paul
Thanks!
That is what I thought about coax so I was surprised by something I thought I read. I couldn't find the reference again when I was looking last night so I probably was mistaken. My main concern was having the right size for the common ground back to the ground bus at the box when the three grounds from the lights are connected at the plug.
That is what I thought about coax so I was surprised by something I thought I read. I couldn't find the reference again when I was looking last night so I probably was mistaken. My main concern was having the right size for the common ground back to the ground bus at the box when the three grounds from the lights are connected at the plug.
Mast Wiring
Coax cable has no electric field outside of its shield. The field is between he conductors only - even if the antenna is not tuned properly. As far as the gauge of the wire used - 14 AGW is plenty for the grounds of all of your lights even if all of them are on at the same time. Think of the wiring in your car lights. The lights on your car are brighter and draw more current, yet you do not see any wire larger that 14 for any of the running lights. The hear light that draw 10 Amps have larger wire. The mast is already grounded to the negative side of the battery by the manufacturer, but I would still run a separate ground for all the lights on the mast. To keep the plug pins from corroding and causing bad contacts - go to an aouto store and buy the kind of dielctric paste used to water proof the spark plug caps on your card. It looks like vaseline.
Coax cable has no electric field outside of its shield. The field is between he conductors only - even if the antenna is not tuned properly. As far as the gauge of the wire used - 14 AGW is plenty for the grounds of all of your lights even if all of them are on at the same time. Think of the wiring in your car lights. The lights on your car are brighter and draw more current, yet you do not see any wire larger that 14 for any of the running lights. The hear light that draw 10 Amps have larger wire. The mast is already grounded to the negative side of the battery by the manufacturer, but I would still run a separate ground for all the lights on the mast. To keep the plug pins from corroding and causing bad contacts - go to an aouto store and buy the kind of dielctric paste used to water proof the spark plug caps on your card. It looks like vaseline.
Expensive grease!
Joe- "go to an aouto store and buy the kind of dielctric paste used to water proof the spark plug caps on your card. It looks like vaseline. " The grease sold specifically for plugs and points is often Krytox grease, about $5 for a 1/2 ounce tube. It's great stuff, but for wiring all you need is silicone grease, aka "High temperature brake grease" "vacuum dielectric grease" and a couple of other names. In the auto stores, $3 for a single ounce tube or $5 for the big six ounce tube, I bought the big one and can afford to be generous about using it.<G> In fact I won't make any connection in the boat or car with it, I've been so impressed at the way a little bit of it keeps corrosion out of crimps and bulb sockets and battery terminals so many other things. Scott- Running all those duplex cables up the mast is a bit redundant. overkill and excess weight aloft. If you really want to splurge, there are some comapnies that sell 4-up and 5-up wiring (i.e. quadplex and quintplex, not just duplex) in one jacket. Even marine grade tinned stranded. It might take some looking to find it, but that gives you just the wires you need, in the extra jacket. Remember that the splices you make at the mast base, at the lights, and the through-deck are all subject to failure, you need to make top-quality splices and then seal them, i.e. wrap them in butyl tape to keep the water out, even if you've used grease on the pins or crimps. A little extra time and money here really pays off long term.
Joe- "go to an aouto store and buy the kind of dielctric paste used to water proof the spark plug caps on your card. It looks like vaseline. " The grease sold specifically for plugs and points is often Krytox grease, about $5 for a 1/2 ounce tube. It's great stuff, but for wiring all you need is silicone grease, aka "High temperature brake grease" "vacuum dielectric grease" and a couple of other names. In the auto stores, $3 for a single ounce tube or $5 for the big six ounce tube, I bought the big one and can afford to be generous about using it.<G> In fact I won't make any connection in the boat or car with it, I've been so impressed at the way a little bit of it keeps corrosion out of crimps and bulb sockets and battery terminals so many other things. Scott- Running all those duplex cables up the mast is a bit redundant. overkill and excess weight aloft. If you really want to splurge, there are some comapnies that sell 4-up and 5-up wiring (i.e. quadplex and quintplex, not just duplex) in one jacket. Even marine grade tinned stranded. It might take some looking to find it, but that gives you just the wires you need, in the extra jacket. Remember that the splices you make at the mast base, at the lights, and the through-deck are all subject to failure, you need to make top-quality splices and then seal them, i.e. wrap them in butyl tape to keep the water out, even if you've used grease on the pins or crimps. A little extra time and money here really pays off long term.
simple is the way to go
i have this same project going myself the wire im using is 16awg 4plex the kind used for direct bury its rated for 600 volt i would recommend two of these up the mast with a pair to each lite make sure you grease and shrink wrap each connection(i use high temp wheel bearing grease and heat shrink tubing) the whole idea is to keep water and air from the exposed wire so oxidation wont take place good for battery terminals also ive rewired semi trucks & trailers for years and i grease all my connections and heat shrink when possible because these things see contaminates you couldnt imagine out there on the road that your boat will never encounter and ive never had to redo them a second time
i have this same project going myself the wire im using is 16awg 4plex the kind used for direct bury its rated for 600 volt i would recommend two of these up the mast with a pair to each lite make sure you grease and shrink wrap each connection(i use high temp wheel bearing grease and heat shrink tubing) the whole idea is to keep water and air from the exposed wire so oxidation wont take place good for battery terminals also ive rewired semi trucks & trailers for years and i grease all my connections and heat shrink when possible because these things see contaminates you couldnt imagine out there on the road that your boat will never encounter and ive never had to redo them a second time
Why run 4-plex ?
I have no need for 4 or more wires running to the top of the mast for one anchor light. The steamer and the deck light are midway up the mast and where I could use a 3-plex for them (2 positive, one common negative), they have different minimum guage requirements so it made more sense to me to run separate duplex cables. Although it may make sense to run the 3-plex with the larger (14 guage) wire. I considered that the bare minimum in wiring could be three primaries with the minimum guage requirement running up the mast to the respective lights and one negative primary daisy chained to the three lights down the mast, but I think the duplex wiring makes life easiest. Gregs diagram pretty much sums it up. I appreciate the comments about the size of the plug at the base of the mast. I will look at this with a more critical eye. Thanks!
I have no need for 4 or more wires running to the top of the mast for one anchor light. The steamer and the deck light are midway up the mast and where I could use a 3-plex for them (2 positive, one common negative), they have different minimum guage requirements so it made more sense to me to run separate duplex cables. Although it may make sense to run the 3-plex with the larger (14 guage) wire. I considered that the bare minimum in wiring could be three primaries with the minimum guage requirement running up the mast to the respective lights and one negative primary daisy chained to the three lights down the mast, but I think the duplex wiring makes life easiest. Gregs diagram pretty much sums it up. I appreciate the comments about the size of the plug at the base of the mast. I will look at this with a more critical eye. Thanks!
I am gonna sound stupid...
I got the diagram of the mast, thank you it's awesome just what I need. I was working on my mast lights this weekend, and found out I had more of a problem than I first thought. My lights are as follows. I have a steaming light, a mast head anchor light and a spreader light on my port spreader. I was hoping that my issues were bulb related that I couldn't get my steaming light to come on with my nav lights. My anchor light has always been hit and miss, some days it's on, others not so much. I took off my steaming light and only one wire was connected. Great, found the problem, but, can't find the other end. I want to rewire the whole mast, just so I know what is what. The wiring drawing makes perfect sense to me and looks like a relatively easy weekend project. But, here is where I might sound stupid. Since the anchor light and the steaming light will never be on at the same time, but the spreader light and the steaming light could be, and the anchor light and the spreader light could be. So, obviously, they all need their own switch. Does the switch go on the postive or negative wire. (I am no electrician) Help!!! Ross in Tampa
I got the diagram of the mast, thank you it's awesome just what I need. I was working on my mast lights this weekend, and found out I had more of a problem than I first thought. My lights are as follows. I have a steaming light, a mast head anchor light and a spreader light on my port spreader. I was hoping that my issues were bulb related that I couldn't get my steaming light to come on with my nav lights. My anchor light has always been hit and miss, some days it's on, others not so much. I took off my steaming light and only one wire was connected. Great, found the problem, but, can't find the other end. I want to rewire the whole mast, just so I know what is what. The wiring drawing makes perfect sense to me and looks like a relatively easy weekend project. But, here is where I might sound stupid. Since the anchor light and the steaming light will never be on at the same time, but the spreader light and the steaming light could be, and the anchor light and the spreader light could be. So, obviously, they all need their own switch. Does the switch go on the postive or negative wire. (I am no electrician) Help!!! Ross in Tampa
Always break the positive
Always break the positive side of a circiut with the switch. Your ground should be uninterupded. Fair Winds Scott On Eagles Wings.
Always break the positive side of a circiut with the switch. Your ground should be uninterupded. Fair Winds Scott On Eagles Wings.
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