A 12V compressor fridge is one of the most important appliances in a campervan electrical system and also one of the most sensitive to poor wiring. If the cable is too small, voltage drop increases and the fridge may struggle to start, run inefficiently or shut down when battery voltage drops overnight.
This guide explains typical cable sizes used for campervan fridges, how voltage drop affects performance, what fuse size to use and how to calculate the correct cable size properly.
For an exact result based on your installation, use the MKGT calculator here:
Open Cable Size Calculator →
Typical 12V Campervan Fridge Current Draw
Most 12V compressor fridges used in campervans, motorhomes and van conversions draw relatively modest running current, but still require correctly sized cable because low-voltage systems are sensitive to voltage loss.
| Fridge size | Typical running current | Notes |
|---|---|---|
| Small compressor fridge | 3–5 A | Short cable runs allow smaller cable |
| Medium campervan fridge | 4–6 A | Most common installation size |
| Large 12V fridge | 5–8 A | Often requires larger cable on longer runs |
Even though current draw is not high, incorrect cable sizing can still affect fridge performance significantly.
Recommended Cable Size for a 12V Campervan Fridge
Typical cable sizes for campervan fridge installations:
| One-way cable length | Recommended cable size | Comment |
|---|---|---|
| Up to 2 m | 1.5 mm² | Suitable for short runs |
| 2–4 m | 2.5 mm² | Common campervan choice |
| 4–6 m | 4.5 mm² | Recommended for longer runs |
Final cable size should always be confirmed using cable length, system voltage and acceptable voltage drop.
Why Voltage Drop Matters for a 12V Fridge
Compressor fridges are sensitive to voltage drop. Even a small voltage loss can prevent the compressor from starting or running correctly.
If voltage at the fridge becomes too low, the fridge may:
- stop cooling correctly
- struggle to start the compressor
- show low-voltage protection warnings
- cycle inefficiently
This is especially common overnight when battery voltage naturally drops.
Check voltage drop for your installation here:
Open Voltage Drop Calculator →
Example Cable Size Calculation
Example installation:
- System voltage: 12V
- Fridge current: 5A
- One-way cable length: 5m
- Voltage drop target: 3–5%
In this case:
2.5 mm² = minimum practical size
4.5 mm² = recommended for improved performance
Use the calculator here:
Open Cable Size Calculator →
Recommended Fuse Size for a 12V Fridge
Fuse size should protect the cable and circuit. A common method is selecting approximately 125% of the running current.
| Fridge current | Typical fuse size |
|---|---|
| 4 A | 5 A |
| 5 A | 7.5 A |
| 6 A | 10 A |
Check fuse sizing here:
Open Fuse Size Calculator →
Best Wiring Layout for a Campervan Fridge
Recommended wiring structure:
Leisure battery → fuse → fuse box → fridge
Best practice:
- install fuse close to the battery
- keep cable runs short
- use quality terminals
- avoid unnecessary cable joints
2-Core Automotive Cable for Campervan Fridges
Most campervan fridge circuits use 2-core flat automotive cable.
- 1.5 mm² for short cable runs
- 2.5 mm² for typical installations
- 4.5 mm² for longer runs
Browse MKGT 2-core cable range here:
Shop 2-Core Automotive Cable →
Use a Calculator for the Exact Cable Size
Correct cable size depends on:
- current draw
- cable length
- system voltage
- acceptable voltage drop
Calculate your installation here:
Open All MKGT Calculators →
FAQ
Can I use 1.5 mm² cable for a 12V campervan fridge?
Yes for short cable runs. Longer installations usually require 2.5 mm² or larger.
Is 2.5 mm² cable enough for a 12V fridge?
Yes in most campervan installations up to around 4–5 metres one-way cable length.
Why does my campervan fridge stop working at night?
This is often caused by voltage drop when battery voltage falls and cable size is too small.
Should a campervan fridge be wired directly to the battery?
Best practice is wiring through a fused distribution circuit connected to the leisure battery.
What fuse should I use for a 12V campervan fridge?
For many fridges drawing around 5A, a 7.5A fuse is a typical starting point.