SB50, SB120 and SB175 identify Anderson connector families, not a universal fuse-sizing rule. Select the housing, contacts, conductor and mating parts together using the manufacturer's exact ratings. A connector must also suit the environment and switching duty.
The three sizes to compare
| Family | Selection question | What to verify |
|---|---|---|
| SB50 | Does the smaller connector suit the circuit and cable? | Contact part number, conductor range and applicable current rating |
| SB120 | Does this intermediate family suit the required cable and space? | Matching housing key, contacts and assembly tooling |
| SB175 | Does the larger family suit the high-current connection? | Continuous duty, permissible load breaking, cable and protection |
Use the Anderson SB series catalogue and the data sheet for the chosen assembly. For example, the current SB50 housing page describes ratings up to 120A under specified conditions. That is why neither a blanket 50A limit nor an automatic 120A allowance is appropriate for every SB50 installation.
SB and Powerpole are different families
The two-pole SB housing is not the same construction as individual stackable Powerpole housings. Do not assume parts interchange. Housing colour and keying can prevent some combinations mating; the matching family, mechanical key and contact details matter more than a seller's generic “Anderson style” label.
Cable and protection still govern the circuit
Suppose an accessory takes 20A continuously. That does not mean any connector advertised above 20A is suitable. Check the conductor size, terminal contact, crimp tool, ambient conditions and protection at the source. Protect a cable from every battery source capable of feeding a fault.
For portable solar, use the actual PV voltage and current, which are different from the controller's battery-side output. Check polarity at both ends and compatibility with the charge controller. Never connect an unregulated panel directly to a battery as a shortcut.
Assembly and use
Obtain the specified contacts for your cable, strip to the manufacturer's dimension and crimp with suitable tooling. Confirm retention in the housing and provide strain relief. Follow marked polarity and verify the completed assembly before energising it; genderless mating does not correct reversed wiring.
A connector is not automatically a rated load-break isolator. Follow the permitted connection/disconnection duty and isolate loads where required. Use environmental protection suited to its location; a cover or similar appearance does not prove a particular ingress rating.
Can different colours connect?
Check the exact keying in the manufacturer catalogue. Do not force or modify housings to defeat a key.
Can I use a larger fuse because the connector is larger?
No. The fuse must protect the complete cable circuit and satisfy the equipment requirements.
Is SB50 always the best choice for portable solar?
Only if its selected contacts, cable, ratings and environment suit the actual array and connection arrangement. A model name alone does not establish compatibility.
Continue with portable solar planning, cable sizing, fuse sizing, the wiring guide and planner.
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Jack Kennedy is a self-builder who has built two vans. He created Roam Wired to simplify conversion planning and share free tools, supported by affiliate links.
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