The number on an Anderson plug housing is not a complete cable-sizing instruction. A safe, reliable connection depends on the housing, the exact contacts, conductor size, cable length, expected current, duty cycle, ambient temperature, crimp quality and circuit protection.
For that reason, there is no single cable size that is correct for every SB50, SB120, SB175 or SB350 installation.
Connector family and contact size are separate choices
Each SB housing accepts a defined range of contacts. The contact barrel must suit the conductor, and the completed contact must lock correctly into the housing. Do not trim conductor strands to force an oversized cable into a smaller contact.
AFS Offroad plug kits are supplied with a specific contact size:
| AFS kit | Included contact size | Common starting point |
|---|---|---|
| SB50 kit | 6 AWG / 6 B&S / 13.3 mm² | Fridge, solar and accessory connections where the full design suits |
| SB120 kit | 4 AWG / 21.1 mm² | Heavier charging and power circuits |
| SB175 kit | 2 AWG / 33.6 mm² | High-current battery or inverter connections |
| SB350 kit | 2/0 AWG / 67.4 mm² | Very high-current applications designed for the connector |
These are the contacts supplied in the AFS kits, not a recommendation that every circuit should use that cable. Check the product details and electrical design before ordering.
What determines the required cable size?
- Continuous and peak current: a compressor or inverter may have a high start-up surge.
- Round-trip cable length: in DC systems, include the positive and negative path when assessing voltage drop.
- Acceptable voltage drop: sensitive equipment may shut down even when the battery is charged.
- Installation method: bundled, enclosed or hot cable can dissipate less heat.
- Ambient temperature: under-bonnet conditions differ from a ventilated canopy.
- Fuse or breaker: protection must be coordinated with the cable and equipment.
- Terminal and crimp quality: a poor joint can add resistance and heat.
Why voltage drop matters in a 12V system
A small voltage loss is proportionally significant in a 12V circuit. Long runs, undersized cable and poor connections can cause a fridge low-voltage cut-out to activate, a charger to underperform or a plug to heat.
Measure the actual route, not the straight-line distance. Include bends, service loops and the return conductor. Use the equipment manufacturer's limit and a recognised cable-sizing method, then have the result checked by a competent installer.
Do not size a circuit from the connector name alone
Manufacturer ratings depend on the contact, conductor, temperature and test standard. Anderson Power Products publishes current and temperature-rise information on its SB® connector product pages. Always use the data for the exact genuine housing and contact being installed.
Crimping is part of the electrical design
The correct cable can still fail if the contact is crimped poorly. Use the tooling and preparation method specified for the contact. The conductor should be clean, fully inserted and mechanically secure. Inspect that the contact has locked into the housing and that no strands or conductive material are exposed.
Do not solder a connection simply to compensate for an incorrect crimp unless the manufacturer specifically permits that method.
Fuse placement and cable protection
A fuse or breaker protects the cable from excessive current; it is not chosen only to match the appliance label. Protection is normally placed close to the energy source so an upstream cable fault is not left unprotected. Systems with energy sources at both ends may need protection at both ends.
Route cable away from exhaust heat, sharp edges, moving parts and water traps. Use grommets, conduit and clamps where appropriate.
Choosing the housing size
Start with the current, cable, contact and installation requirements, then choose the connector family that supports them and fits the available space. Our SB50 vs SB120 vs SB175 comparison explains the physical and application differences.
Pre-installation checklist
- Current draw and surge are documented.
- Round-trip cable length is measured.
- Voltage-drop target comes from the equipment requirements.
- Housing, contact and cable sizes are compatible.
- Fuse or breaker rating and placement are documented.
- Approved crimp tooling is available.
- The mount has enough rear clearance and strain relief.
- A qualified auto electrician has checked high-current work.
Final word
Treat the connector, contacts, cable and protection as one system. Choosing a bigger plug does not repair an undersized cable or poor crimp, and a large cable is not useful if it does not fit the specified contact correctly.
Important safety information
Water protection: Dust covers, mounting gaskets and connector mounts discussed in this guide are not waterproof or watertight. Install them in a protected location away from direct spray, high-pressure water and immersion.
Electrical installation: All electrical wiring and installation must be carried out by a suitably qualified electrician or auto electrician, as appropriate. The installer must confirm cable sizing, terminations, fusing, circuit protection and suitability for the application.