What connections for 16/0.2mm droppers?

[Ravenser]

I think I used 16/02 wire for droppers on Blacklade which is DCC . Almost certainly massive overkill. But you can get away with that  in 4mm where the rail is bigger and the sleeper gaps much bigger too

 

The current small N gauge project is using 7/0.2 droppers, and often two to a piece of track. This is still awkward to solder to the rail. I mention this because I know Lacathedrale has 2mm interests, and I'm not clear what scale the project in question is

 

With Blacklade the whole lot was wrapped round stripped solid mains cable and soldered. For the current project I'm taking the wires back to tag strip - and I'm finding that you run out of space on a tag to take wires.16/02 becomes quite impractical for droppers inder those conditions

 

[WIMorrison]

I solder 16/0.2 to the side of the code 80 rail used in my 9mm gauge track without issues.

[Ravenser]

On 21/07/2022 at 18:20, Miss Prism said:

RS Stock No: 433-781

 

 

And how do you fix in place when you need less than 30 tags??

 

I've managed to fix sections some similar stuff with eyelet fixing of the tags using 3/4" panel pins through the eyelets, but it's an ugly bodge. And the strip in your picture has no eyelet holes.

Edited August 15, 2022 by Ravenser

[rab]

On 25/07/2022 at 13:39, DCB said:

For strict prototype authenticity use a a nut and bolt and connect the rail ends...

What size would the bolts be in N gauge :)

[Miss Prism]

22 minutes ago, Ravenser said:

And how do you fix in place when you need less than 30 tags??

 

Cut strip to suitable length. Remove a tag, to reveal a convenient fixing hole. The most commonly used arrangement (for undertrack droppers) will be tag hole tag.

 

[Enterprisingwestern]

On 23/07/2022 at 20:35, AndyID said:

Yes, the "fusing current" (the current at which the conductor will actually melt) for 7/0.2 copper wire (equivalent to 24 AWG) is greater than 29 amps

 

I reckon if any of us can create 29 amps out of less than 20 volts AC or DC layout voltage we're in the wrong job!

 

Mike.

Quite happy with his 7/02 droppers on dcc!

[WIMorrison]

It isn't the fusing current capacity that you need to be concerned about, it is the voltage drop that you get with thinner wires - especially if you have long runs of wire, as the drop can be significant when load is applied, and you will not see that drop with a meter.

[AndyID]

3 minutes ago, Enterprisingwestern said:

 

I reckon if any of us can create 29 amps out of less than 20 volts AC or DC layout voltage we're in the wrong job!

 

 

Not that difficult if you have a convenient car battery 😀

[Enterprisingwestern]

Just now, AndyID said:

 

Not that difficult if you have a convenient car battery 😀

 

Don't tempt me, in frustrating times it could be an option!

 

Mike.

[AndyID]

2 minutes ago, WIMorrison said:

It isn't the fusing current capacity that you need to be concerned about, it is the voltage drop that you get with thinner wires - especially if you have long runs of wire, as the drop can be significant when load is applied, and you will not see that drop with a meter.

 

You certainly will see that drop with a meter. Why would you think you will not? In the grand scheme of things all wires (other than super-conductors) have resistance.

[WIMorrison]

Because a meter, especially a digital meter, doesn’t draw enough current to show the drop.

 

You need something that is drawing current to make the drop evident. The power loss is exponentially dependent upon the current drawn.

[spamcan61]

5 minutes ago, WIMorrison said:

Because a meter, especially a digital meter, doesn’t draw enough current to show the drop.

 

Indeed, Ohm's law shall prevail; I saw this in action a few years back where a section of track on my train set seemed OK with  a DVM but testing with a bulb as a load showed that there was a resistive/dry joint to the track.

[AndyID]

9 hours ago, WIMorrison said:

Because a meter, especially a digital meter, doesn’t draw enough current to show the drop.

 

You need something that is drawing current to make the drop evident. The power loss is exponentially dependent upon the current drawn.

 

Surprisingly, voltmeters are designed to draw as little current as possible 😀

 

Also, there won't be any voltage drop in a circuit that is not passing current.

[Ravenser]

1 minute ago, AndyID said:

 

Surprisingly, voltmeters are designed to draw as little current as possible 😀

 

Also, there won't be any voltage drop in a circuit that is not passing current.

 

Don't you use the resistance metering, not the voltage,  set to the most sensitive possible band? That really should test the resistance through the wiring

 

[WIMorrison]

30 minutes ago, AndyID said:

 

Surprisingly, voltmeters are designed to draw as little current as possible 😀

 

Also, there won't be any voltage drop in a circuit that is not passing current.

 

When testing circuits e.g. model railways you should do an open circuit measurement to see what voltage is present and establish a baseline. The easiest way to do this is to disconnect the controller from the layout and measure the output at the back of the controller.

 

You then undertake a second test with a load on the model, and at the furthest point from the supply input. This can be the usual stock, however if this is limited or very modern therefore drawing little current, a car indicator bulb is an ideal load as this will be 21w which means 1.5-2A current draw (depending on supply input). If there is a difference between the baseline and the loaded measurement then you have either

 

•  a power supply that is too low and needs uprating to provide, or
• a resistance caused by wire that is too light thus causing a power loss due to internal resistance
• a poor connection or contact, possibly a cold or dry solder joint, broken wires going into a screw connector (extremely common), dirty wire at connections, ...

When a difference between the baseline and measured value is different, then fault-finding needs to be done to establish where the fault lies.

 

Simply sticking a voltmeter on a circuit and reading it is useful, but only if you know what the reading actually means.

[AndyID]

4 hours ago, Ravenser said:

 

Don't you use the resistance metering, not the voltage,  set to the most sensitive possible band? That really should test the resistance through the wiring

 

 

Unless there is a very poor connection somewhere in the circuit a multimeter won't help much. The resistance values of interest are fractions of one ohm.