This is the 30 Amp connector.

The recommended configuration is shown above. If you take the time to pre-assemble the connector bodies per the pictorial above, as you receive your shipment, you will find it much easier to assemble the connectors for use and there will be no ambiguity in plus minus connections.

When you finish crimping the spade lug to the wire, insure you re-form the crimped portion to round. This will allow easy insertion into the plastic connector body. The easiest crimp tool to get is the Gardner Bender GS-88 available at Ace Hardware or Home Depot for about $8 plus tax.

Many recommend soldering the connections instead so they are reusable and more secure.

To assemble the wire/spade-lug and the plastic body, insure you - firmly - press the wire/spade-lug into the plastic body with the 'hooked' side of the spade lug facing the metal plate in the body as shown. There will be a distinctive click as the wire/spade-lug locks in to the plastic body.

Diagram used with permission of Anderson Interconnect Inc., manufacturer of the Anderson Powerpole connectors.