Connections

Crimped connections are preferable to soldered connections. Bad crimped connections are easier to identify than bad solder joints. Additionally, it is easier to fix a bad crimp in the field since it does not require powered tooling.

If you’re making a crimped connection, use a proper crimp tool if at all possible. Pliers are not an acceptable alternative (see ESRA safety critical wiring guidelines). We have proper crimp tools for: generic butt splice and ring/spade connectors, Dupont and JST connectors, and RJ45 connectors.

Use ferrules for stranded wire that goes into a screw terminal.

Crimped connections should be done on stranded wire only. 

Wire should only be soldered to connectors that are specifically made for it (e.g. connectors with solder cups). Stranded wire should be used in the vast majority of cases since solid core wire becomes brittle and prone to breakage (exception: wire soldered onto protoboard should be solid core).

All solder joints should be strain relieved with zip-ties or P clamps.

 If you screw up a soldering job, redo the job. When soldering surface mount components, inspect solder joints with a small magnifying glass.

All connections must be tug-proof.

The amount of exposed wire should be minimized and the insulation should come as close to the connector as possible. All exposed wire should be heat-shrunk; all heatshrink should be clear (IREC regulation).

If a connector could be asymmetric (keyed), it should be asymmetric, since asymmetric connectors are much harder to plug in backwards.

Use locking connectors wherever possible. A plastic clip is better than nothing, but any sort of screwed locking mechanism is preferable.

All battery connectors should be terminated in a female connector to prevent battery shorting and enable easy battery swapping.