Anderson Plugs Explained: Sizes, Wiring and Common Faults

Anderson-style plugs are the heavy-duty DC connectors used to link a vehicle to a camper trailer, a solar blanket or a portable fridge battery. They're genderless, so two identical plugs join face to face.

1. The common sizes

The number is the maker's current rating in amps under their test conditions. Genuine plugs are rated to their spec sheet. Cheap copies may not reach it.

2. The plug doesn't set the current, the cable does

The fuse at each end protects the cable. A 50A plug on a thin cable is still a thin cable. Size the cable for the current and the run length, then pick a plug rated above that current.

3. Wiring it

• Use the right size contact for the cable, and crimp it with a proper crimper for that size. A pliers-squashed crimp heats up.
• Push each contact in until it clicks behind the spring.
• Keep the same layout on every plug you own: positive on the same side, so you can't swap polarity.
• Use a dust cap when it's unplugged.

4. Warning signs

• Warm or hot plug after a run: poor crimp, dirty contacts or undersized cable.
• Discoloured or melted housing: stop using it and replace the plug and the damaged cable.
• Plug falls apart easily: worn springs. Replace it.

5. Quick summary

• Rating is the plug's limit, not the circuit's. Size the cable first.
• Crimp properly, click the contacts in, keep polarity consistent.
• A hot plug is a fault, not normal.

Work on 240V AC wiring, including inverter outputs and mains inlets, must be done by a licensed electrician. For high-current DC gear, follow the maker's installation manual and have an auto electrician check your work if you're unsure.

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