How do I hardwire a dash cam, and when should I not?

Before you start: switched or permanent?

• Switched (ignition) live. Nextbase says this makes the camera turn on and off with the vehicle and protects the battery when the engine is off. Choose it if you just want a tidy install without a socket plug.
• Permanent live. Needed for parking mode. Nextbase's support article says Parking Mode requires a constant power supply when the ignition is off, and that a switched fuse disables it. Only do this with a kit that has low-voltage protection: the Nextbase Series 2 kit listing describes a built-in voltage limiter that protects the battery on a permanent live feed.

What you need

• A hardwire kit made for your camera brand. The Nextbase kit includes ATO/C and ATM fuse tap cables, 2 A fuses and a 5 m Mini USB lead.
• Your car's owner's manual with the fuse box chart.
• A multimeter or 12V test lamp to confirm which fuses are switched and which are permanent.
• A plastic trim tool, cable ties, and a fuse puller.

Steps

1. Mount the camera first, behind the rear-view mirror, so you know where the cable has to reach. Our guide tochoosing a dash cam mountcovers placement.
2. Find the fuse box the kit's lead can reach (often in the passenger footwell or the end of the dashboard) and identify candidate fuses from the manual chart.
3. Test each candidate. With the ignition off, probe the fuse; then with the ignition on. A fuse live only with the ignition on is switched; one live in both states is permanent. Steer clear of airbag, SRS, braking or engine management circuits even if they test correctly.
4. Fit the fuse tap. Remove the original fuse, put it in the tap's slot for the car's circuit, put the kit's own low-rated fuse in the other slot, and push the tap into the fuse position. Follow the kit diagram for which way round it goes.
5. Earth the kit. Fix the earth ring under a bare metal bolt on the body. BlackVue's guide specifies a solid metal ground bolt on the vehicle chassis.
6. Route the cable up from the footwell, along the A-pillar and into the headlining to the camera. BlackVue's guide is explicit: never run cables across side-curtain airbags, always route behind the airbag housing. Tuck the cable into the door weatherstrip or behind the trim, never over the face of the pillar trim where an airbag deploys.
7. Test before refitting trim. Check the camera starts with the ignition and, for parking mode, use Nextbase's check: engine off, and look for a lightning bolt through the battery icon.

When not to hardwire

• You cannot identify the fuses with certainty.Nextbase's own advice is to always consult a qualified installer to select the correct fuse and complete the installation.
• You do not need parking mode and your 12V socket already switches off with the car. A plug-in lead does the same job with no wiring.
• The car is rarely driven. Nextbase says its cameras are not designed for continuous 24/7 operation and advises unplugging them for long periods without driving, which a permanent hardwire install makes awkward.
• It is a short-term car. Nextbase suggests its OBD kit is better suited to temporary or quick installations.

Common mistakes

• Tapping a fuse by guesswork from the chart without testing it.
• Fitting the fuse tap the wrong way round, so the car's circuit or the camera feed is not protected as intended.
• Earthing to a painted panel or a plastic bracket.
• Running the cable across the face of the A-pillar trim over a curtain airbag.
• Wiring to a permanent live fuse without any low-voltage protection.
• Concentrating on the wiring and mounting the camera where it intrudes into your view of the road; keep it tucked behind the mirror.

Related pages

• Can a car charger drain the battery?
• Does a 12V socket work with the engine off?
• Is a rear dash cam worth it?
• Dash cam features explained
• Best dash cams

Frequently asked questions

Should I use a switched or a permanent live fuse?

Use a switched (ignition) fuse if you only want the camera recording while you drive: Nextbase says this makes the camera turn on and off with the car and protects the battery. Use a permanent live fuse only if you want parking mode, which Nextbase says needs a constant power supply when the ignition is off.

Which fuse should I tap?

One whose circuit you can identify from the owner's manual fuse chart and test with a multimeter or test lamp, such as the accessory socket or radio for a switched feed. BlackVue gives cigarette lighter or radio as examples of ignition-only fuses, and hazard lights or interior lights as examples of constant ones. Avoid anything labelled for airbags, SRS, braking or engine management. Nextbase's advice is to consult a qualified installer to select the correct fuse.

Is an OBD power cable easier than the fuse box?

It avoids the fuse box entirely, but Nextbase describes its OBD hardwire kit as better suited to temporary or quick installations than permanent setups. It is a reasonable option for a car you will not keep long.

Can I use the Nextbase kit with another brand of camera?

No. The listing says the Series 2 hardwire kit is designed for Nextbase Series 2 cameras and is not compatible with Series 1 or other brands. Other makers sell their own: the 70mai A510 listing, for example, names specific 70mai hardwire kits.

How do I know the hardwire install worked?

Start the car and check the camera powers up and records. If you wired to a permanent live fuse for parking mode, Nextbase suggests turning the engine off and checking for a lightning bolt symbol through the battery icon on the screen. If the camera shows a low-battery warning instead, it is probably on a switched fuse.