How to Power an Outdoor Security Camera

The view is set; now, where does the power come from? Working out how to power outdoor security camera positions early decides the cable you pull, the boxes you mount and whether the job needs an electrician. This guide compares the outdoor camera power options and works through the voltage drop that catches long low-voltage runs.

Outdoor camera power options compared

Each method trades installation effort against how much the camera can do once it is up.

Our guide to wired vs wireless security cameras covers the recording side of that choice. This one stays on power.

PoE: one cable for power and video

Power over Ethernet sends power and data down the same twisted pair cable, so the mount needs no receptacle and no separate power wire. The switch or recorder sits indoors, and one UPS at the head end keeps every camera running through an outage.

Two checks decide whether PoE works at a given spot: the switch must have enough power left for the camera’s class, and the run must stay within the Ethernet distance limit. Our PoE budget guide for IP cameras covers the first, and Cat5e vs Cat6 for security cameras covers cable choice and outdoor jacket types.

Low-voltage power: 12 VDC adapters and 24 VAC transformers

Analog and HD-over-coax cameras, and some IP cameras, take a separate low-voltage feed. Read the label or spec sheet first: it states 12 VDC, 24 VAC, or both, and the current draw.

• Plug-in adapter: simple for one camera near a receptacle. Keep the adapter indoors or in a weatherproof box, never hanging in the open.
• Central power supply: a cabinet with several individually fused outputs, mounted indoors beside the recorder. One location to service, and it can share the recorder’s UPS; see sizing a UPS for an equipment rack.
• Polarity: 12 VDC has a positive and a negative lead, and reversing them can damage a camera. 24 VAC has no polarity.

Use a listed Class 2 supply sized above the total load, with headroom for IR and heaters at night.

Voltage drop on long low-voltage runs

Current flows out on one conductor and back on the other, so the wire resistance that matters is twice the run length. Voltage drop equals current times that loop resistance. A camera that works in daylight and drops out when its IR switches on at night is the classic sign.

The worked example below rests on stated assumptions: one camera drawing 0.5 A, solid copper conductors at 20 C, and resistance only (reactance ignored, which is reasonable for 60 Hz at these lengths). Resistance per 1,000 feet comes from the Georgia State University HyperPhysics wire gauge table: 6.385 ohms for 18 AWG, 4.016 for 16 AWG and 2.525 for 14 AWG.

Compare the result with the camera’s rated input range. HyperPhysics notes that real resistivity varies by a few percent with purity and manufacture, and warm wire or copper clad aluminum conductors lose more.

Why 24 VAC suits long runs

For the same power, doubling the voltage halves the current, so the drop in volts halves too, and as a share of the supply it falls to a quarter. That is why long runs and heated or PTZ cameras are often powered at 24 VAC. The other fixes are heavier wire, a shorter run, or a supply closer to the camera.

Battery and solar security camera power

A battery camera needs no cable, so it suits a gate post or a detached shed. The battery life on the box is the maker’s estimate for typical use; a busy view, cold weather and long night recording all shorten it.

A solar security camera adds a panel that tops the battery up. It works when the panel sees direct sun for most of the day:

1. Face the panel toward the sun (south in the United States), clear of trees, eaves and neighboring buildings through the whole day.
2. Plan for winter, when days are short, the sun is low and snow can cover the panel.
3. Use the panel and battery the camera maker specifies, and keep the lead short and dripped.

Weatherproof connections and outdoor cable

A splice left open to rain is an easy way to lose a camera. Make every connection inside a weatherproof back box or junction box, or in the camera’s own base, and leave a drip loop so water runs off before it reaches the entry. Use connectors rated for damp or wet locations.

• Cable: sunlight resistant jacket for exposed runs, direct burial or conduit underground.
• Boxes: match the rating to the exposure; see our guide to NEMA enclosure ratings.
• Height: fix the mount position before the power drop; see security camera mounting height.

When the job needs a licensed electrician

Adding an outdoor receptacle, extending a branch circuit or wiring a transformer into a junction box is electrical work, and in many jurisdictions it needs a licensed electrician and a permit.

The National Electrical Code, as adopted locally, generally calls for GFCI protection on outdoor receptacles and a weatherproof in-use cover in wet locations. Keep Class 2 camera cable out of boxes and raceways that carry line voltage unless the code permits it. Check the local code before you quote the job.

Where to find cameras and power-ready cable

The wireless cameras category lists fixed, pan/tilt and indoor/outdoor IP cameras, and the security cameras category lists IP domes and bullets. PoE switches are in the network switches category, and Cat5e and Cat6, including outdoor and direct burial types, in the security wire category, all part of the security, surveillance and control division.

For pricing and availability, ask your sales representative through the Bursma contact page or call the Wyoming, Michigan branch. If you install for a living, apply for a Bursma dealer account.

Frequently asked questions