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A question about lights and switches and splicing into cables.
- Thread starter CamperJack
- Start date
i think your diagram needs a bit of a 
rehash....
rehash....
you need to move the right hand puck connections to the far left near the left puck then put the puck switch in the positive feed to the pucks..
funflair
LIFE MEMBER
I hope you are wrong s there are 100's in our van
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CamperJack
Free Member
i think your diagram needs a bit of a
This better?
Would you just move the switch so the splicing in for the reading lamps is before the puck switch or would you wire it totally differently? How would you do it? I'm very keen to learn from the more experienced!
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looks electrically correct , i would keep the switch separated as you have drawn it. I dont know what wattage is likely to be drawn if all lights were on so you may want to look at the size of the cable from the fuse box as that is carrying everything
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CamperJack
Free Member
Thanks Phil.
They are all LED lights so very low consumption.
The reading lights are 3W each, which is 0.25A on 12V. 0.25A X 4 = 1 A. The puck lights are 0.2A X 2 = 0.4 A.
Total 1.4 Amps for everything on the bed system.
Using this cable size calculator (https://tinyurl.com/y2jf6q6e) and putting in 2% loss, 12V, 1.4 amps I can use 2.5mm cable for up to 10 meters cable length.
I was going to use 6mm because I have some. But I might buy some smaller wire to make running it easier. Perhaps 3mm? Open to ideas / suggestions though, as always.
They are all LED lights so very low consumption.
The reading lights are 3W each, which is 0.25A on 12V. 0.25A X 4 = 1 A. The puck lights are 0.2A X 2 = 0.4 A.
Total 1.4 Amps for everything on the bed system.
Using this cable size calculator (https://tinyurl.com/y2jf6q6e) and putting in 2% loss, 12V, 1.4 amps I can use 2.5mm cable for up to 10 meters cable length.
I was going to use 6mm because I have some. But I might buy some smaller wire to make running it easier. Perhaps 3mm? Open to ideas / suggestions though, as always.
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CamperJack
Free Member
I hope you are wrong s there are 100's in our van
I'm quite possibly thinking about something else. I think this is something everyone you ask will have a different opinion on.
Put the switch and fuse box where you want them.
Run wire between the two.
Connect from the closest reading light to either of those points.
Daisychain the other reading lights to the first using the shortest/easiest routes.
The switch is probably good, because you can put two wires into the same crimp on the input to the switch. And that brings me to cable sizes - 1.4A is the square root of fcuk all. 1.5mm2 cable is overkill, never mind 6mm2.
Which brings us to another point to check - when you say 6mm what do you mean? The cross sectional area of the copper? The diameter of the copper, or the diameter of the whole thing?
The correct one is cross sectional area. If you see (a number) AWG on a cable that's something different again!
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CamperJack
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What I normally work with the stated rating. In this case the "6mm" multi-strand is rated at 53 amps (https://tinyurl.com/yyug4szn). Massively oversized so will buy thinner for ease of running them.
Will daisy chain still work it each reading light is switched on the base? These lights: (<Broken link removed>).
I'm going by this calculator for cable size.
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Ok, yes, buy thinner.
Yes, you're connecting to it before it's switch.
Don't. lol. There are a few things wrong with your entries. It's not 12V we're using. You can accept a much greater loss %age in this situation (possibly even helpful as a lot of LED's are designed for 12V, not the 14. something you might see. It's rubber cable, at 30 degrees C etc.
The table a bit down this page is more useful:
DC cable selection guide
I have recently installed solar and dual bettery systems on two buses, refreshed my own installation and am starting to think like an electrical engineer. After some extensive research, I have prod…
stephenstuff.wordpress.com
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CamperJack
Free Member
Don't. lol. There are a few things wrong with your entries. It's not 12V we're using. You can accept a much greater loss %age in this situation (possibly even helpful as a lot of LED's are designed for 12V, not the 14. something you might see. It's rubber cable, at 30 degrees C etc.
The table a bit down this page is more useful:
DC cable selection guide
I have recently installed solar and dual bettery systems on two buses, refreshed my own installation and am starting to think like an electrical engineer. After some extensive research, I have prod…
2.5mm (29amp) okay for these lights?
Minxy
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I can tell you from first hand experience that they Wago blocks may let go of the wires, when we got a previous Globecar Familyscout L van one of the light strips over the bed didn't work which was a bummer. I located the Wago blocks and worked out which was which (Germans like to use blue & brown wires and its not always consistent as to which is live and neutral!), whilst checking the wiring I found that one of the wires for the light was loose so lifted the 'clamp' on the block, reinserted the wire, and clamped it soundly in place, it never came out again. Whether this issue was down to the block itself or that the wire hadn't been fully inserted originally I don't know. One thing to make sure of when using Wago blocks is that the insulation is cut back sufficiently on the wire to allow it to be fully inserted to ensure a good tight fit.
Also, what size fuse were you thinking of using?
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CamperJack
Free Member
The system is 1.4 amps so 1.4 X 1.25 = 1.75. Round it up to 2 amps.
That’s just above the normal operating conditions and well below the rating of the wire.
That’s just above the normal operating conditions and well below the rating of the wire.
TheBig1
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As already mentioned, scotchloc connectors are the work of the devil, made for lazy DIYers who know no better. Soldering can introduce a point of failure very easily if not supported, due to hardening and vibration.
The best solution is a good solid mechanical connection, like a crimp connector. Even better still use combined crimp and heatshrink connectors to reduce the risk of corrosion, a constant issue on any vehicle.
Run each bank of lights in a parallel daisy chain using piggyback crimps, positive to positive and negative to negative with the positive side being switched. This will allow the reading lights to be independently switched on the base. You can cluster groups of lights before the switch to fuse more than one light circuit for simplicity. Using LED lights means you are drawing very low current overall. Count the lights and used amps up, add a small margin for addition and fuse accordingly. A wire csd of 6mm is massive overkill for a lighting circuit, is heavier and less flexible. If you are using best practice and running wiring in trunking, flexible is best and smaller csd wiring is far easier to pull through and allow for any future circuits
Back to crimps, buy a decent set of crimping pliers, as they give a good joint without over or under crimping leading to failures. A half decent set of ratchet crimping pliers is only about £20, and will be a great addition to any toolbox
The best solution is a good solid mechanical connection, like a crimp connector. Even better still use combined crimp and heatshrink connectors to reduce the risk of corrosion, a constant issue on any vehicle.
Run each bank of lights in a parallel daisy chain using piggyback crimps, positive to positive and negative to negative with the positive side being switched. This will allow the reading lights to be independently switched on the base. You can cluster groups of lights before the switch to fuse more than one light circuit for simplicity. Using LED lights means you are drawing very low current overall. Count the lights and used amps up, add a small margin for addition and fuse accordingly. A wire csd of 6mm is massive overkill for a lighting circuit, is heavier and less flexible. If you are using best practice and running wiring in trunking, flexible is best and smaller csd wiring is far easier to pull through and allow for any future circuits
Back to crimps, buy a decent set of crimping pliers, as they give a good joint without over or under crimping leading to failures. A half decent set of ratchet crimping pliers is only about £20, and will be a great addition to any toolbox
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CamperJack
Free Member
My initial thought was piggy back crimps but something in my little head, when giving it some thought, had this idea that the spades might fall out and so I decided on scotchlock. Popular consensus seems to be the reverse. Back to plan A and piggybacks?
Would you use a piggy back to splice off the positive wire to the puck lights before the switch to provide a positive line for the reading lamps?
Would you put a big piece of heat shrink over the entire piggy back connector, or just where the wire enters it or both?
I bought a ratchet crimper for about £20 on eBay and it broke. Ratchet stuck shut on the second connection. I also have a pair of ten ton hydraulic crimpers. They're fantastic and also about £20. https://tinyurl.com/10TCrimps Also hand crimpers.
Thanks for the helpful post!
- Mar 14, 2019
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Came across this which will help. Note they state that LED pucks must always be in series, ie daisy chained so the negative goes back to the power source, only the positive goes through the LED's in a chain. the link below explains it all.
- Mar 14, 2019
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Having re-read the posts the link I gave in my last post gives the size of cables and the length of a cable run before significant voltage drop, up to 250 metres with 32 LED's and 0.75mm2 cable. Note also that it is only the end LED in the chain which is connected to the negative, all others are connected in the chain. The information is very full for creating a chain of LED's
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The way to do this is so it can be adjusted/ removed easily, if i was you i would fit one of these terminal blocks near to where your positive and negative feed is and run two different circuits for each light type, one for the main bedroom lights to switches and one for the reading lights with integral switches, this way you can isolate either if there is a problem. make sure your supply to the terminal block is fused or alternatively get a fused block. the Waco connectors are fine, and replaceable by the way.
Terminal block - http://rover.ebay.com/rover/1/710-5...0001&campid=5338547443&icep_item=153302970885
Fused Block - Amazon product ASIN B07SGQ3QNRAmazon product ASIN B085NQ9H98
Terminal block - http://rover.ebay.com/rover/1/710-5...0001&campid=5338547443&icep_item=153302970885
Fused Block - Amazon product ASIN B07SGQ3QNRAmazon product ASIN B085NQ9H98
This site contains affiliate links for which MHF may be compensated.
Strip the two wires, twist and put into one fully insulated crimp.
Like, but with the correct crimp:
Nothing extra to fall apart, short out etc.
Perfect.
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CamperJack
Free Member
So you wouldn’t use piggy back?
No. They are a weak point, have a lot of un-insulated area and are 2 crimps when you could just do one.
This has far less chance of anything going wrong if crimped correctly:
Amazon product ASIN B00XWDMHC6
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CamperJack
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