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17 September 2007, Robert Madson
This Extension describes modifications and additions to the Smart-N standard, for the purpose of using Anderson PowerPole connectors for inter-module electrical joiners.
Use of this Extension, or any Extension, is optional. It is recommended that an organization choose a consistent set of Extensions, and use that set for all of its modules.
The Smart-N standard uses jumper wires to electrically join modules at their interfaces. While this method is cheap and reliable, it is also somewhat cumbersome, as each pair of joined interfaces requires inserting eight wire ends into the proper terminals. It's easy to insert a wire into the wrong hole, and difficult to find such mistakes by visual inspection. It's also easy to lose the jumper wires between shows, which can cause delays and frustration when setting up.
NTrak has adopted Anderson Powerpole connectors as a new Recommended Practice, to eventually supplant the older Cinch-Jones (CJ) connectors. While MARRS rejected the CJ connectors for both its HO and N modular standards, the PowerPoles appear to address most of the problems of the CJs. More importantly, when compared to Smart-N's current jumper-wire system, the PowerPoles offer faster and less error-prone setup and take-down.
 Red and black PowerPole shells, and a contact wiper. Note the "hood" and "peg" on each shell. |
Each connector has a C-shaped "hood" and a rectangular "peg" molded into it. By convention, the hood is the "top" of the connector and the peg is the "bottom." An electrical connection is made by turning one PowerPole upside-down relative to another and pushing them together end-to-end; therefore, there are no "male" or "female" PowerPoles.
PowerPole connectors are available in different amperage ratings, based on the size of wire they are designed to accept. For example, 15-amp PowerPoles accept 18-22 gauge wire; 30-amp PowerPoles accept 12-16 gauge wire. The 15-, 30-, and 45-amp versions use the same shell, and can be freely intermixed. Higher-rated connectors are progressively larger, and cannot be intermixed.
 PowerPoles joined "red over black." Note the hood and peg positions. |
The current Smart-N standard is unchanged by this Extension, with the following exceptions.
It is not necessary to supply jumper wires with PowerPole-equipped modules; however, "pigtail" adapters may be needed when interoperating with non-PowerPole-equipped modules. (See 6. Backward Compatibility" below.)
It is recommended to use European-type barrier strips on PowerPole-equipped modules, instead of spring terminals. (However, spring terminals are still acceptable.)
The following requirements are in addition to those in the Smart-N standard.
Each interface will be equipped with two "pigtails," each consisting of a length of 18-gauge, two-conductor wire fitted with PowerPole connectors at one end and stripped (and optionally tinned) leads at the other. Each pigtail will have one red PowerPole and one black PowerPole. Recommended: if red/black zip cord is available, it should be used, with the colors matching the PowerPoles.
Each pigtail will connect with its associated mainline at the terminal strip for the interface. The pigtails should be long enough to extend 6 to 12 inches beyond the interface when pulled taut.
When looking at the interface from the end of the module, the left mainline will have a pigtail installed with the left rail connected to the red PowerPole, the right rail connected to the black PowerPole, and the PowerPoles joined red over black. The right mainline will have a pigtail installed similarly, except with the colors reversed.
Thus, the four rails of the mainlines are color-coded red-black, black-red from left to right. The PowerPoles are joined red-over-black, black-over-red from left to right, in the same pattern.
By keeping extra pigtails available, backward compatibility with non-PowerPole-equipped modules can be easily maintained. The pigtails can be temporarily installed on such a module, in the place of the "normal" jumper wires, following the pattern described in section 5.2 "Connector Wiring" above. Once the need has passed, the pigtails can be removed.
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Email:
Rob Madson, MARRS Web POC and Site Maintainer
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