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Premium Member
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Discussion Starter · #1 ·
Hi All,

Can i run 12V DC for track power and accessories /16V on the same D connector my thought are to have 12V track power on two of the pins for a shuttle the same on another two pins for a seperate track and the same for 12V accesories /16V using 8 pins in total on one connector is this safe and possible


Any help would be appreciated.
 

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Just another modeller
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9,983 Posts
Yes you can do it, no the pins and their mount shells aren't rated for high current use. I'm always conservative with power wiring so when I use a D connector which is rarely, I use TWO wires for each power wire, with only ONE power source per connector, and use spare pins for any small current purpose such as detection etc....

Having said the above they are used reasonably often by modellers on a one pin per wire basis, so for a small layout with a lesser power system and carefully wired, they will survive as connectors as long as a full short isn't left cooking for too long.

But - My one warning. Its not good to mix active external power connections with the DCC power bus wiring.

Be VERY careful with the wiring to the plugs, be tidy and heatshrink each terminal of the D's properly - if you touch external 12v to the output of your DCC system, even for a moment, you will risk killing the DCC system.

Richard
 

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Premium Member
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Discussion Starter · #4 ·
Hi Richard,
Many thanks for the advice it want to use a D connector in my cue case layout so DCC wont be involved a D control or similar is fine to run the track as the maximum track length will be only 50'' so the ends of the track will be open.

I wanted to use the D connector as space is limited fitting it at one end with an experimentor box holding the control and any other accesories switches shuttle unit etc.

On all D connector pins i apply heatshrink
.
 

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293 Posts
The rating of D Connectors varies considerably with price, quality, manufacturer and construction.
As has been mentioned, a typical connector you might obtain from a model show or shop is unlikely to have a sufficiently high current rating for DCC.
However, better quality types can be found, rated at 5A per pin if you can justify the cost.
Alternatively, you can use more than one pin for each connection to spread the current if that suits you instead (usually adjacent pins would be used for convenience). Even military equipment sometimes uses this technique to save having to use special mixed contact connectors with their even more horrendous price tags!

Heatshrink over each joint is definitely worth the effort to reduce the risk of shorts occurring should any strands come loose (which they shouldn't, but it can happen).
Most people shy away from using 50 way D connectors though, because they have three rows of pins and it can be difficult to access the middle row for maintenance should it become necessary.
 

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Hi
I have used sub D connectors on several dc operated model railways and particularly when connecting a mimic panel to the layout. You can mix suplies and voltages within one D connector.
9 and 25 way versions are normally used (Avoiding the 15 pin three row version as its a swine to solder wires onto).
The solder buckets inside the connector accept 16/02mm wire with reasonable ease. Pre solder tin wire ends and also fill the buckets with cored solder before entering the tinned wire end into the heated bucket. Remove iron and don't move the wire until the solder has solidified (about 5 - 7 seconds).
I also slip a short length of heat shrink tubing over every other wire prior to soldering, then the tubing is slid down over the cooled bucket and wire joint and shrunk down to form a total insulation sleeve insulating it from the adjoining pins.
The Maplin sub D is rated at 7.5amps per pin, but I seriously doubt if that sort of current will be seen on a model railway per wire!
I use D connectors on all track feeds, point motor feeds, signal feeds, and where a common return is used, I have doubled up adjacent pins to help improve the higher currents through these connections Though technically and according to the manufactures data they don't need doubling!
Maplin Sub D connectors
 

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Chief cook & bottle washer
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One simple tip when you solder wires to a D plug. Make sure you have the male and female plugs joined up, so that you don't have pins dropping out of line if the plastic gets a bit soft with the heat.
 

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An alternative approach is to buy completely assembled cables, cut them in half and use small terminal blocks or solder tags to connect a section of layout to a cut cable end. Fit the other end of the cable to the next section in similar fashion. This avoids the soldering to the small plugs which some people find too fiddly to do.

Such cables can often be found second-hand and going cheaply at car boot sales and other places but may need to be checked with a multimeter before use to ensure all pins are connected.

Regards,
John Webb
 

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I wouldn't advise using ready made cables as suggested, because although the pins in the connectors themselves might be OK, the wires they are attached to are unlikely to be rated sufficiently for DCC use. Such cables are normally meant for low current applications such as printer connections. You may also find that not all the ways are wired through, even if the pins are there in the connectors. Buyer beware!
 
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