How do I wire an Anderson plug?

Quick answer

Choose the plug and contact size to suit your cable (for most 12V accessory and charging jobs, a 50 A Anderson-style connector with 6 B&S or 8 B&S contacts). Crimp the contacts on with a proper crimp tool, push them into the housing until they click, and wire every plug the same way round so positive always meets positive. Fuse the positive cable close to the battery, and fit a cover on any plug that’s live when unplugged.

Is this a DIY job?

• Difficulty: Medium
• Time: 15 to 30 minutes per plug
• Tools: cable cutter, wire stripper, Anderson-style crimp tool (hex or ratchet type sized for the contact), heat gun, multimeter
• Skills: crimping heavy cable properly

The plug itself is simple. The quality of the crimp is what matters: a poor crimp gets hot under load.

Step by step

1. Pick the right connector and colour. The SB50 suits most fridges, solar panels and DC-DC charger inputs. The SB120 and SB175 are for high-current jobs. The real rating depends on the contact and cable, so match the contact to your cable size. Use the same housing colour as the plugs already on your vehicle and trailer, or they won’t join.
2. Choose your cable. Use twin-core cable sized for the current and the length of the run. (see What size cable do I need for my 12V accessory?)
3. Disconnect power. If the cable is connected to a battery, remove the fuse or disconnect the battery first.
4. Strip the cable. Strip only enough insulation for the copper to sit fully in the contact barrel, with no bare copper showing past the barrel.
5. Crimp the contacts. Put each contact in the correct die of the crimp tool and crimp firmly. Tug hard on each one: it must not move. Don’t use pliers or a hammer crimper unless it’s designed for that contact.
6. Add heat shrink over the back of the contact and cable if the contact design allows it.
7. Decide your polarity convention and stick to it. Anderson-style connectors are genderless: two identical plugs join by turning one over. Hold each plug with the face towards you and the same edge up, and put positive on the same side every time. Then any two plugs you wire will join positive to positive. If you’re adding plugs to an existing setup, check how the existing plugs are wired and match them.
8. Insert the contacts. Push each contact into the housing from the back until it clicks behind the spring. Pull gently to check it’s locked.
9. Check polarity with a meter. Before connecting anything, measure at the plug face and confirm positive is where you expect it. Then plug two plugs together and confirm positive reaches positive.
10. Fuse it. The positive cable must have a fuse or circuit breaker close to the battery or power source, sized to protect the cable. (see Where should the fuse go when wiring an accessory?)
11. Mount and cover it. Use a mounting bracket or dust cover, especially for plugs on bumpers or drawbars that stay live.

Specs table

Common Anderson-style sizes

Anderson Power Products makes the genuine SB series. The number in the name (SB50, SB120, SB175) is a size, not a promise: the current a connector can actually carry depends on the contact fitted and the cable crimped into it. A small contact in a big housing is only as good as the small contact.

All three are rated to 600 V by the maker. In a 12V vehicle the limit is always current and heat, never voltage.

Contact sizes

Choose the contact to match the cable, and the cable to match the current and run length. (see What size cable do I need for my 12V accessory?)

Housing colours and voltage

The housing colour is a voltage key. Genuine housings of different colours have different moulded keys, so in general they won’t plug into each other. That’s meant to stop a 12V plug being joined to a 24V or 48V system. Anderson Power Products’ recommended colour key is:

In Australian 12V fit-outs the maker’s key often isn’t followed. Grey housings are widely used for 12V, and red is common on 12V battery boxes and power leads. The key only protects you if every plug in your system uses the same colour. Check what’s already on your vehicle, trailer and accessories before you buy, because a plug of a different colour won’t join them.

What you’ll need

• Anderson plug 50A (with contacts to suit your cable)
• Anderson plug crimp tool
• twin core auto cable (size for your load and length)
• adhesive heat shrink
• Anderson plug cover or Anderson plug mounting bracket
• inline fuse holder or circuit breaker

When to call an auto electrician

• You’re wiring a charging circuit for a caravan or trailer battery, especially with a DC-DC charger or a smart alternator.
• The cable runs the length of the vehicle, through the firewall or near airbag zones.
• An Anderson plug or its cable gets hot in use. That points to a bad crimp, a loose contact or undersized cable.
• You need SB120 or SB175 connectors with heavy cable.

Related questions

Q: Which side is positive on an Anderson plug? A: There’s no single rule printed on the plug. What matters is that every plug you use is wired the same way when viewed the same way up, so positive always meets positive. Check with a multimeter.

Q: Can I solder Anderson contacts instead of crimping? A: A correct crimp with the right tool is the common method for these contacts. Whatever method you use, the joint must be mechanically strong and not get hot under load.

Q: Why did my Anderson plug melt? A: Usually a poor crimp, a contact not fully seated, corrosion, or more current than the cable or connector can carry.

Q: Do I need a fuse if I have an Anderson plug? A: Yes. The plug isn’t a fuse. Every positive cable needs a fuse or circuit breaker close to its power source.

Sources

1. Anderson Power Products, SB50 connector datasheet (via Farnell) – 50 A rating, 16–6 AWG contact range, genderless design, colour-keyed housings. https://www.farnell.com/datasheets/273617.pdf (checked October 2026)
2. Anderson Power Products, SB50 datasheet (via Farnell) – silver-plated contacts for 6 AWG (13.3 mm²), 8 AWG (8.4 mm²) and 12–10 AWG (3.3–5.3 mm²); “genderless design mates with itself”. https://www.farnell.com/datasheets/3046067.pdf (checked October 2026)
3. Anderson Power Products, SB50 connector datasheet – recommended voltage key colour code (yellow 12V, orange 18V, red 24V, grey 36V, blue 48V and higher); 600 V rating. https://www.e-kart.fr/images/stories/technique/anderson/sb50-connector.pdf (checked October 2026)
4. Anderson Power Products, SB120 datasheet (via Mouser) – 190 A UL rating at 75°C with largest cable; #6 to #1 AWG contacts. https://www.mouser.com/catalog/specsheets/DS-SB120(7)%5B1%5D.pdf (checked October 2026)
5. Anderson Power Products, SB175 datasheet – 175 A UL rating at 65°C with largest cable; #4 to 1/0 AWG range plus a #6 contact; colours used to identify voltages. https://static.chipdip.ru/lib/221/DOC011221459.pdf (checked October 2026)
6. Home of 12 Volt (Australian 12V supplier), red to grey 50 A Anderson adaptor – genuine Anderson colours don’t mate with other colours; grey used for 12V, while many newer battery boxes and 12V leads use red. https://www.homeof12voltonline.com.au/products/red-50-amp-anderson-to-grey-50-amp-anderson-genuine-andersons (checked October 2026)
7. Narva, heavy-duty 50 amp connector housing (red) – red 50 A housing sold for chargers, inverters and fridges; keyed to prevent accidental connection. https://www.narva.com.au/products/57200R/heavy-duty-50-amp-connector-housing-red (checked October 2026)