Terminal block connectors (choc box)

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The Sligo Rover
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Terminal block connectors (choc box)

#1

Post by The Sligo Rover » Thu Mar 12, 2020 8:04 am

Help the novice again please, I have plenty of the 3 amp version but I think I read somewhere that I should use 5 amp.
This would be for my DCC bus and accessory bus.
Also, the common return wire for accessorise, can it be the bare earth wire stripped from mains cable or is it better to use an insulated cable?

Tricky Dicky
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Re: Terminal block connectors (choc box)

#2

Post by Tricky Dicky » Thu Mar 12, 2020 10:11 am

If you are DC then I would say you are OK, DCC controllers can deliver several Amps, Lenz for instance can deliver 5amps. So you would need to uprate. Solenoid motors can draw a current of 4-5amps but it is momentary so should not present a major issue except where you are firing several motors at once.

Using uninsulated wires always presents a risk of a short circuit and although it is possible to manage that, I do not see what is gained over using insulated cable so I would not recommend it. Be aware that using a common return will carry the sum of all the currents on the layout so it needs to be a much heftier cable than any others.

Richard

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Brian
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Re: Terminal block connectors (choc box)

#3

Post by Brian » Thu Mar 12, 2020 10:39 am

3 Amp connectors are fine. However, you need to ensure when using these and assuming two (or more) wires can be secured inside the connectors tube, that each wire is stripped of its insulation material so as its long enough so that the bare end goes right into the connector and reaches the far end. Thereby creating an overlapping of two or more wires inside the connector tube and both screws then grip down on all the wires inside the connectors tube. The fact of getting two or more wires inside a 3Amp connectors tube may be the limiting factor and 5Amp or larger connectors may be required. Personally I would purchase 5Amp type from the beginning. ;)

These are 5Amp blocks used on my last DCC layout.
Image

As for using the bare copper wire stripped from former main cable. Where perhaps the two insulated wires are used for other feeding - DCC bus pair etc is ok but only if it can be securely fixed throughout its full length. I have used a 1.5mm2 bare earth wire on a fixed layout without any issues, but it was securely clipped around the layouts undersides and only used for the common return of point motors and building and street/platform lighting return. I would not recommend that a bare wire be used on a portable layout as there is far more risk of it being moved accidentally during handling etc In fact I do not recommend using any solid core wire on a portable layout due to the risk of a wire fracturing.
All the layout rails are bare conductors and these don't normally cause issues, unless they are shorted by a tool or loco derailing! :D

Red & Black DCC Bus pair runs with a bare common return 1.5mm2 return wire
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The Sligo Rover
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Re: Terminal block connectors (choc box)

#4

Post by The Sligo Rover » Thu Mar 12, 2020 12:46 pm

Many thanks again for all your expert guidance. 5 amp connectors it is so off to Screwfix or Toolstation to get them in ready in case my soldering technique is not up to scratch. My layout (wood work done) will hopefully move on a bit more now that I have this vital information.

RFS
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Re: Terminal block connectors (choc box)

#5

Post by RFS » Fri Mar 13, 2020 10:55 pm

Have you considered Wago (and lookalike) connectors for your DCC bus connections? For example, these 8-way ones (price is for 10 of them) https://www.banggood.com/10Pcs-PCT-218- ... rehouse=CN

You just connect one wire to your bus and up to 7 wires to individual rails. Each connection can take more than one wire provided they are the same gauge. There are 3 and 5-way options too. Much easier than soldering under the baseboard.

Plenty of options on Ebay also - search under Wago.
Robert Smith

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