Short answer: the number in an Anderson SB plug's name (50, 120, 175) is a rough current, not a hard limit. The real rating depends on the cable, the crimp and the conditions. The colours are mechanical keys, so only matching colours plug together, and Anderson's own colour code doesn't make grey 12 V. Go by the labels on your gear, not by assumption.
What does the "50" in SB50 actually mean?
It's a nickname more than a limit. Anderson's SB50 datasheet gives several ratings, each from a different test:
- UL rating, wire-to-wire with 6 AWG: up to 120 A.
- CSA rating: 50 A.
- IEC: 50 A, tested with 16 mm² wire.
- Hot plugging (connecting or disconnecting under load): rated to 50 A, over 250 cycles at 120 V DC.
Every one of those assumes ideal conditions: 105°C-rated cable of the largest size, Anderson's own properly calibrated crimp tooling, a 25°C ambient, and the rating is per position with all positions loaded.
So a 120 A figure doesn't mean an SB50 on thin cable, crimped with pliers, in a hot engine bay, will carry 120 A. Size the cable for the job first (our cable sizing guide covers that), then pick a plug that takes that cable.
What size Anderson plug do I need?
Start from the cable. Here's what Anderson say each size takes and is rated for:
| SB50 | SB120 | SB175 | |
|---|---|---|---|
| Wire sizes | 16 to 6 AWG | 10 to 1 AWG (5.3 to 42.4 mm²) | 10 to 1/0 AWG (5.2 to 53.4 mm² in the catalogue) |
| UL rating, wire-to-wire | 120 A (6 AWG) | 240 A (1 AWG) | 280 A (1/0 AWG) |
| CSA rating | 50 A | 130 A | 175 A |
| IEC amp rating | 50 A (16 mm² tested) | 120 A (50 mm² tested) | not given |
| Hot plugging | 50 A | not given | 100 A |
Anderson's own documents don't line up in a few spots. The SB50's metric range is 1.5 to 16 mm² on the datasheet's front page but 1.3 to 13.3 mm² in its table. An older Anderson sheet rates the SB120 at 190 A on 1 AWG, where the current datasheet says 240 A. And the SB175's largest wire is 53.4 mm² in the catalogue but 50 mm² on the product page.
None of that changes the big picture, but it's a good reason to buy the contact that matches your cable and use the right crimp tool, rather than forcing a cable into the nearest plug.
All SB connectors are rated to 600 V (UL 1977), so on a 12 V or 24 V system, current and cable decide the size.
Is an Anderson plug a fuse?
No. It's a connector, and nothing in Anderson's ratings makes it protection. That's the fuse's job, and our fusing guide covers where fuses go and how to size them.
What do the colours mean?
The colour shows the mechanical key. SB plugs are genderless, so a plug mates with its twin, and only housings with the same key fit together. The colour is how you tell the keys apart.
So a grey plug mates with a grey plug, a red with a red, and grey and red won't go together. Anderson say the point is to keep different circuits apart and stop people accidentally plugging different voltages together. The colour doesn't limit the voltage the connector can handle.
There are exceptions to "only matching colours mate":
- SB50 black and grey share the same key and plug into each other.
- The SB175 black housing has no key and mates with every other colour.
- More generally, Anderson warn that some SB50, SB175 and SB350 housings in different colours share a key.
Does grey mean 12 volts?
Not by Anderson's code. Their catalogue's recommended voltage colours are:
| Voltage | 12 V | 18 V | 24 V | 36 V | 48 V | 72 V |
|---|---|---|---|---|---|---|
| Colour | Yellow | Orange | Red | Grey | Blue | Green |
(It carries on: 80 V black, 96 V brown, 120 V purple, 144 V white.) Anderson say it follows the voltages industrial trucks, batteries and chargers have adopted as a standard.
Gear makers don't necessarily follow it. Exotronic's own pre-wired boards use colours to mark a job rather than a voltage, and don't even agree with each other:
- Coorong: solar input on a red Anderson, starter battery on a grey one.
- Noosa 50 Plus: starter battery on a blue Anderson, solar on a grey one.
We couldn't find a published Australian colour convention from a maker or a standard, so don't assume one. The practical rule is simpler:
- Use different colours for things that must never be plugged together, like a solar input and a battery output.
- Label both ends, and check the colour on the gear you're plugging into before you buy the other half.
- Be careful with black SB175s and the SB50 black/grey pair, since they mate across colours.
If you're fitting a pre-wired board, our guide to pre-wired boards vs DIY covers what you connect yourself.
Can I mix genuine and copy plugs?
Anderson's catalogue says only Anderson housings should be mated with each other, and that mating non-Anderson parts with theirs "will void UL certifications, warranties, and liability". That's Anderson's position on their own ratings; if the figures above matter to you, use genuine Anderson housings on both sides.
Where do I find them?
Our genuine Anderson connectors include the SB50 grey, SB50 red, SB120 grey and SB175 grey. Lugs and other connectors are in connectors and lugs.