What is the best way to wire a mast. I am palnning on having an anchor light, steaming light w/ foredeck light, and spreader lights. Is it ok for all the grounds from each component go to the anchor light ground wire? So should I use this triplex wire or should use just individual wires for each component? Also, I was going to wrap a 4 zip ties every 12" so I wouldn't get all the nosie from wires hitting the inside of the mast. Thanks for all the replies
Mast wiring
- Thread starter Traumaguard
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Your plan should work
Your plan is exactly what I did and it came out great. I ordered quadplex wire, a foredeck/steaming light, a masthead light, and a couple quick disconnects from west marine and installed it. Did just as you said, put tie downs every 1.5 feet or so in a star pattern and everything has been working great. The only reason I put in disconnects what that in the case that i want to take the mast down i have an easy way to disconnect the wiring from the deck. JayK Oday 25
Your plan is exactly what I did and it came out great. I ordered quadplex wire, a foredeck/steaming light, a masthead light, and a couple quick disconnects from west marine and installed it. Did just as you said, put tie downs every 1.5 feet or so in a star pattern and everything has been working great. The only reason I put in disconnects what that in the case that i want to take the mast down i have an easy way to disconnect the wiring from the deck. JayK Oday 25
Forgot to mention i used seperate ground wires
Forgot to mention that I used seperate ground wires for each light to avoid the all or nothing working if one of the connections went bad. Not sure if this was correct though......
Forgot to mention that I used seperate ground wires for each light to avoid the all or nothing working if one of the connections went bad. Not sure if this was correct though......
Common
As JayK indicated, common grounds are not the preferred method. If you do use a common ground, it should be upsized to accomodate the highest current that could resuilt from multiple light circuits on. The size is dependant upon ampacity & length (voltage drop). Goto: The charts at: http://cruisersforum.com/photopost//showphoto.php?photo=1850 http://cruisersforum.com/photopost//showphoto.php?photo=1321 http://cruisersforum.com/photopost//showphoto.php?photo=1322 “Ohm’s Law & You” at: http://cruisersforum.com/photopost//showphoto.php?photo=1315 http://cruisersforum.com/photopost//showphoto.php?photo=1316
As JayK indicated, common grounds are not the preferred method. If you do use a common ground, it should be upsized to accomodate the highest current that could resuilt from multiple light circuits on. The size is dependant upon ampacity & length (voltage drop). Goto: The charts at: http://cruisersforum.com/photopost//showphoto.php?photo=1850 http://cruisersforum.com/photopost//showphoto.php?photo=1321 http://cruisersforum.com/photopost//showphoto.php?photo=1322 “Ohm’s Law & You” at: http://cruisersforum.com/photopost//showphoto.php?photo=1315 http://cruisersforum.com/photopost//showphoto.php?photo=1316
Zip ties
I saw a suggestion that when running wire in the mast to NOT cut the ends off the cable ties. The end acts like a little standoff, keeping the wire from slatting around inside the mast. Maybe mounting each one 90 degrees from its neighbor would help that. YMMV.
I saw a suggestion that when running wire in the mast to NOT cut the ends off the cable ties. The end acts like a little standoff, keeping the wire from slatting around inside the mast. Maybe mounting each one 90 degrees from its neighbor would help that. YMMV.
Proper way
After looking at Gord's links (Thanks Gord). You can select the proper wire sizes. You may not use smaller than 16ga wire for the lights unless you use duplex cable (18ga wire is allowed in duplex). The grounds should be separate. The masthead (steaming) light and deck light combo may share a ground. The masthead light is a COLREG requirement and has to wired to nav light specs. (3% voltage drop max IIRC) I prefer to run a duplex cable to each lamp from the panel. If there is a fault, you can replace one wire at a time. You cannot replace one wire from a bundle that is zap strapped together, the whole harness has to come out. If you have internal halyards, don't even think about letting the wires bang around inside the mast. The halyards will remove them soon enough. The wires must run inside a conduit to keep them from playing with the halyards.
After looking at Gord's links (Thanks Gord). You can select the proper wire sizes. You may not use smaller than 16ga wire for the lights unless you use duplex cable (18ga wire is allowed in duplex). The grounds should be separate. The masthead (steaming) light and deck light combo may share a ground. The masthead light is a COLREG requirement and has to wired to nav light specs. (3% voltage drop max IIRC) I prefer to run a duplex cable to each lamp from the panel. If there is a fault, you can replace one wire at a time. You cannot replace one wire from a bundle that is zap strapped together, the whole harness has to come out. If you have internal halyards, don't even think about letting the wires bang around inside the mast. The halyards will remove them soon enough. The wires must run inside a conduit to keep them from playing with the halyards.
Avoid #16
Assuming a load of approximately 2 Amps (25Watt @ 12.8 Volt), # 16 Wire (Rated 25 Amps*) would result in a 3% Voltage Drop (max. permitted) over a total circuit run of under 40 feet (18.75' each + & -). See the previously linked Wire Sizing Chart (Amp/Ft) - #16AWG Cu = 75 Amp/Feet (Load Amps x Total Feet of Wire) Not very useful for the typical longer runs required for Nav’ Lighting. * ABYC permits much higher ampacities than the NEC, which would only rate #16 @ 16A (Free-Air)
Assuming a load of approximately 2 Amps (25Watt @ 12.8 Volt), # 16 Wire (Rated 25 Amps*) would result in a 3% Voltage Drop (max. permitted) over a total circuit run of under 40 feet (18.75' each + & -). See the previously linked Wire Sizing Chart (Amp/Ft) - #16AWG Cu = 75 Amp/Feet (Load Amps x Total Feet of Wire) Not very useful for the typical longer runs required for Nav’ Lighting. * ABYC permits much higher ampacities than the NEC, which would only rate #16 @ 16A (Free-Air)
Gord? You selling wire by the pound? 
Avoid #16? Check the math. You can run a #90 Bulb on a 150ft circuit with 3% drop on 16ga. Anyone here have a nav light that is 75 feet away and a 12V system? Gord is correct about the 25W/2A-75ft circuit needing larger than 16ga. However the only 25W lights on a mast are the spreader lights if you use the old tractor style sealed beams. Most Nav lights are less than 10 Candle Power, so none of the standard 12V lamps draw more than 1 amp @ 12.8V. The #90 lamp that is used in many nav lights is 6CP, 7.5W, .58A @ 12.8. A 75 foot run with a .6 amp current calls for 18ga, 16ga is overkill, 14ga is just silly. Ancor Marine has a wire calculator on their site. Get the information on the actual lamps you use, measure the runs and select the wire.
Avoid #16? Check the math. You can run a #90 Bulb on a 150ft circuit with 3% drop on 16ga. Anyone here have a nav light that is 75 feet away and a 12V system? Gord is correct about the 25W/2A-75ft circuit needing larger than 16ga. However the only 25W lights on a mast are the spreader lights if you use the old tractor style sealed beams. Most Nav lights are less than 10 Candle Power, so none of the standard 12V lamps draw more than 1 amp @ 12.8V. The #90 lamp that is used in many nav lights is 6CP, 7.5W, .58A @ 12.8. A 75 foot run with a .6 amp current calls for 18ga, 16ga is overkill, 14ga is just silly. Ancor Marine has a wire calculator on their site. Get the information on the actual lamps you use, measure the runs and select the wire.
Voltage Drop Calc's
Moody: To paraphrase Wolfgang Pauli, You’re math isn’t right - it isn’t even wrong. I’d respectfully suggest you read “Ohm’s Law & You” available at: cruisersforum.com/photopost//showphoto.php?photo=1315 cruisersforum.com/photopost//showphoto.php?photo=1316 Or, if you don't have the time to understand the priciples, at least look at the chart and explanatory notes at: cruisersforum.com/photopost//showphoto.php?photo=1321 cruisersforum.com/photopost//showphoto.php?photo=1322 A 0.6 A 12.8V circuit length of 150 feet (total pos + neg) would require #14AWG Cu wire, to maintain < 3% Vd. Of course the theoretical calculation makes no allowance for the additional resistance(s) that terminations add - and the significant additional Voltage Drop they impose on a real-world circuit. Even at retail prices*, the incremental cost of #14 vs #16 wire would be about $1.50 (for 150 feet total). Of course, the use of #18 (vs #14) could save you the magnificent sum of $15.00 total. * Budget Cu Primary Wire Prices (by the foot): #18 @ $0.19 #16 @ $0.29 #14 @ $0.30 #12 @ $0.45 I have no idea why you introduce candlepower into the discussion. Candlepower is a measure of a lamp’s luminous source output, and has no direct relationship to the power (Watts) required to drive a given lamp. The modern terminology is Mean Spherical Candelas (MSCD) and is the total light output from a lamp measured in all directions. Respectfully, Gord May
Moody: To paraphrase Wolfgang Pauli, You’re math isn’t right - it isn’t even wrong. I’d respectfully suggest you read “Ohm’s Law & You” available at: cruisersforum.com/photopost//showphoto.php?photo=1315 cruisersforum.com/photopost//showphoto.php?photo=1316 Or, if you don't have the time to understand the priciples, at least look at the chart and explanatory notes at: cruisersforum.com/photopost//showphoto.php?photo=1321 cruisersforum.com/photopost//showphoto.php?photo=1322 A 0.6 A 12.8V circuit length of 150 feet (total pos + neg) would require #14AWG Cu wire, to maintain < 3% Vd. Of course the theoretical calculation makes no allowance for the additional resistance(s) that terminations add - and the significant additional Voltage Drop they impose on a real-world circuit. Even at retail prices*, the incremental cost of #14 vs #16 wire would be about $1.50 (for 150 feet total). Of course, the use of #18 (vs #14) could save you the magnificent sum of $15.00 total. * Budget Cu Primary Wire Prices (by the foot): #18 @ $0.19 #16 @ $0.29 #14 @ $0.30 #12 @ $0.45 I have no idea why you introduce candlepower into the discussion. Candlepower is a measure of a lamp’s luminous source output, and has no direct relationship to the power (Watts) required to drive a given lamp. The modern terminology is Mean Spherical Candelas (MSCD) and is the total light output from a lamp measured in all directions. Respectfully, Gord May
Well someones math is different
Gord, I don't mean to argue, but after checking the math, I have to stand by my choice of 16AWG wire. My math is just fine, thanks. Say hello to Wolfgang for me. The formula I use is: CM = (K x I x L) / E Where: CM = circular mils K = 10.8 (for copper) I = current in amps L = total conductor length in feet E = voltage drop in volts For our 150 foot total run: 10.8 x .6 x 150 = 972 3% of 12.8 = 0.384 972/0.384 = 2531.25 circular mils 16 AWG wire is 2,583 CM, borderline yes, but still correct. 14 AWG wire is 4,107 CM, and sounds like overkill to me. I see the article you wrote uses 10.75 for K, giving slightly lower CM numbers than the 10.8 figure I use. Using 10.75 calculates to 2519.5 CM, less than the 2531 I came up with. The 150 foot run is near the theoretical maximum for a typical .58A #90 12V bulb using 16AWG wire. The typical masthead light has a run of 75-80 feet and 16AWG is just fine. 14AWG wire won't fit into many USCG approved lights for one simple reason, 16AWG is plenty big enough. Many new boats come with 16ga wire in the mast harness and carry ABS/LLOYDS/CE certification. In fact fitting 14AWG wire to fixtures that were quite properly designed around 16AWG wire can require modifications that reduce the reliability of the system. I mentioned CP, because at one time the range of the light we use was related to candle power and marine bulbs are still rated that way. Could you point me at a more current source of information? Of course you are correct that poor connections and terminations can increase the resistance of a circuit. Has it been your experience that normal practice of using tinned marine grade AWG wire, proper crimps, and ring terminals adds enough to the circuit to require larger wire?
Gord, I don't mean to argue, but after checking the math, I have to stand by my choice of 16AWG wire.
My math is just fine, thanks. Say hello to Wolfgang for me. The formula I use is: CM = (K x I x L) / E Where: CM = circular mils K = 10.8 (for copper) I = current in amps L = total conductor length in feet E = voltage drop in volts For our 150 foot total run: 10.8 x .6 x 150 = 972 3% of 12.8 = 0.384 972/0.384 = 2531.25 circular mils 16 AWG wire is 2,583 CM, borderline yes, but still correct. 14 AWG wire is 4,107 CM, and sounds like overkill to me. I see the article you wrote uses 10.75 for K, giving slightly lower CM numbers than the 10.8 figure I use. Using 10.75 calculates to 2519.5 CM, less than the 2531 I came up with. The 150 foot run is near the theoretical maximum for a typical .58A #90 12V bulb using 16AWG wire. The typical masthead light has a run of 75-80 feet and 16AWG is just fine. 14AWG wire won't fit into many USCG approved lights for one simple reason, 16AWG is plenty big enough. Many new boats come with 16ga wire in the mast harness and carry ABS/LLOYDS/CE certification. In fact fitting 14AWG wire to fixtures that were quite properly designed around 16AWG wire can require modifications that reduce the reliability of the system. I mentioned CP, because at one time the range of the light we use was related to candle power and marine bulbs are still rated that way. Could you point me at a more current source of information? Of course you are correct that poor connections and terminations can increase the resistance of a circuit. Has it been your experience that normal practice of using tinned marine grade AWG wire, proper crimps, and ring terminals adds enough to the circuit to require larger wire?
Sample Installation
This is how I do it when I build a mast: 42ft mast with Masthead/Decklight Combo, Anchor light, and 2 spreader lights AquaSignal Series 25 combo light. Height above deck 25 feet. The masthead light is rated 10W, the deck light is rated 20W 10W = 0.78125 Amp @ 12.8 volt 20W = 1.5625 Amp @ 12.8 volt If it takes 20 feet of wire to get from the panel to the mast, the total run is 45ft x 2 = 90ft The 10W masthead light requires 3% vd for 1968 CM, and 16AWG is called for. The deck light can use 10% vd for 1181 CM, and 16AWG is fine for the 20W bulb as well. The maximum length for 16AWG to the 10W light is 118 feet or 59 feet from panel to light. The Anchor light is 42 feet off the deck, plus 20 to the panel for 62 feet. We cannot use a .78A bulb on 16AWG wire, the total run is 124 feet. If 18AWG (OMG!) wire is chosen the 124ft run, it can handle a maximum of .460A. Anchor lights that draw as little as .110A are available. Two 25W spreader lights will draw almost 4amps on a 95 foot total circuit. Using a 10% vd, 14AWG wire is called for. The total install will be: 90ft of 16AWG for 6.1 pounds 124ft of 18AWG for 4.6 pounds 95ft of 14AWG for 6.2 pounds 16.9 pounds of wire. If 14AWG is used for all 309ft, the weight is over 20 pounds. Using properly sized wire and components saves over 3 pounds of weight aloft. If the spreader lights are left off (we already have a deck light), another 6 pounds of wire is saved, plus the weight and windage of the lights on the spreaders. Manufacturers are constantly trying to save weight. Performance sailors spend big $$$ to save weight aloft. Blocks, halyards and rigging are selected to save ounces, why waste the effort by using 14AWG where 16 or 18 will save pounds? 14AWG to the top of the mast would support a 50W load, what are we going to do up there? Read? When a mast is built, I prefer schedule 20 PVC conduit rather than schedule 40 (half the weight). If I can use 3/4" diameter instead of 1" diameter by selecting wire sizes for each light, more weight can be saved. Where else on a boat can you save weight and money at the same time? Why do it any other way?
This is how I do it when I build a mast: 42ft mast with Masthead/Decklight Combo, Anchor light, and 2 spreader lights AquaSignal Series 25 combo light. Height above deck 25 feet. The masthead light is rated 10W, the deck light is rated 20W 10W = 0.78125 Amp @ 12.8 volt 20W = 1.5625 Amp @ 12.8 volt If it takes 20 feet of wire to get from the panel to the mast, the total run is 45ft x 2 = 90ft The 10W masthead light requires 3% vd for 1968 CM, and 16AWG is called for. The deck light can use 10% vd for 1181 CM, and 16AWG is fine for the 20W bulb as well. The maximum length for 16AWG to the 10W light is 118 feet or 59 feet from panel to light. The Anchor light is 42 feet off the deck, plus 20 to the panel for 62 feet. We cannot use a .78A bulb on 16AWG wire, the total run is 124 feet. If 18AWG (OMG!) wire is chosen the 124ft run, it can handle a maximum of .460A. Anchor lights that draw as little as .110A are available. Two 25W spreader lights will draw almost 4amps on a 95 foot total circuit. Using a 10% vd, 14AWG wire is called for. The total install will be: 90ft of 16AWG for 6.1 pounds 124ft of 18AWG for 4.6 pounds 95ft of 14AWG for 6.2 pounds 16.9 pounds of wire. If 14AWG is used for all 309ft, the weight is over 20 pounds. Using properly sized wire and components saves over 3 pounds of weight aloft. If the spreader lights are left off (we already have a deck light), another 6 pounds of wire is saved, plus the weight and windage of the lights on the spreaders. Manufacturers are constantly trying to save weight. Performance sailors spend big $$$ to save weight aloft. Blocks, halyards and rigging are selected to save ounces, why waste the effort by using 14AWG where 16 or 18 will save pounds? 14AWG to the top of the mast would support a 50W load, what are we going to do up there? Read?
When a mast is built, I prefer schedule 20 PVC conduit rather than schedule 40 (half the weight). If I can use 3/4" diameter instead of 1" diameter by selecting wire sizes for each light, more weight can be saved. Where else on a boat can you save weight and money at the same time? Why do it any other way?
Now are we really missing one point?
I've sailed at night with voltage dipping below 11. Why are we doing theory on 12.8v? I bet we really can well justify 16 if we go to 14.6v and keep the motor running. Don't those lights just brighten up when the motor is running. Wires and connections after a few years do seem to start to corrode. Is it really the answer to not overkill on a long run of wire? "Just right" today stays just right how long? I've seen 12 volts on a digital meter to a light socket... but the corrosion limited the amps to the point the bulb would not glimmer. For small change ... go the bigger wire on long runs. By the way in Amateur Radio land ... we never question using heavier low voltage power wires than the recommended. We have "low-voltage" phobias. Vic "Seven" ww4ok
I've sailed at night with voltage dipping below 11. Why are we doing theory on 12.8v? I bet we really can well justify 16 if we go to 14.6v and keep the motor running. Don't those lights just brighten up when the motor is running. Wires and connections after a few years do seem to start to corrode. Is it really the answer to not overkill on a long run of wire? "Just right" today stays just right how long? I've seen 12 volts on a digital meter to a light socket... but the corrosion limited the amps to the point the bulb would not glimmer. For small change ... go the bigger wire on long runs. By the way in Amateur Radio land ... we never question using heavier low voltage power wires than the recommended. We have "low-voltage" phobias. Vic "Seven" ww4ok
Hook it up....
The comments about the ABYC codes are correct. Soldering should be avoided to comply. That said, a good, well protected, solder joint in an area that can't flex or is subject to vibration is still inherently superior to a crimp connection. That eliminates most uses on a boat. I would not try to 'get by' with a single ground lead. Every fixture should have its own complete circuit. What happens if that single ground wire breaks....nothing works. It's more wire, more work, but well worth it. As far as the mast wiring layout, when I rewired my mast, I had the mast on saw horses and laid out my wires next to it to have a feel for proper lengths and exit points. I used foam pipe insulation with heavy cable ties every 16 - 18 in...absolutely no mast slap. The old wiring in my mast was all 12ga, and since I figured Peason knew what they were doing, I replaced with 12ga. Actually for a long run like this, even though it's only 12v, nothing less than 14ga should even be considered, since the wire will be heavier and 'tougher' than lighter gauges, and less suseptible to damage. The hard part, is trying to find connectors where you go through the deck, etc that will accept 12ga wire...or even 14ga for that matter. Good luck....
The comments about the ABYC codes are correct. Soldering should be avoided to comply. That said, a good, well protected, solder joint in an area that can't flex or is subject to vibration is still inherently superior to a crimp connection. That eliminates most uses on a boat. I would not try to 'get by' with a single ground lead. Every fixture should have its own complete circuit. What happens if that single ground wire breaks....nothing works. It's more wire, more work, but well worth it. As far as the mast wiring layout, when I rewired my mast, I had the mast on saw horses and laid out my wires next to it to have a feel for proper lengths and exit points. I used foam pipe insulation with heavy cable ties every 16 - 18 in...absolutely no mast slap. The old wiring in my mast was all 12ga, and since I figured Peason knew what they were doing, I replaced with 12ga. Actually for a long run like this, even though it's only 12v, nothing less than 14ga should even be considered, since the wire will be heavier and 'tougher' than lighter gauges, and less suseptible to damage. The hard part, is trying to find connectors where you go through the deck, etc that will accept 12ga wire...or even 14ga for that matter. Good luck....
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