"Low voltage" is everything in a building that carries data, video or control signals instead of line power: network cabling, fiber, security cameras, access control, Wi-Fi, paging and AV. If you are planning an office build-out, a warehouse, a tenant improvement or an upgrade in Boise, Meridian, Nampa or Eagle, this guide explains the parts, the numbers and the decisions you will be asked to make, so you can read a quote and know what you are paying for.

Quick answer: A commercial low voltage contractor designs and installs the cabling and devices that run on power-limited circuits: Cat6/Cat6a and fiber, network racks, PoE switches, Wi-Fi access points, security cameras and access control (readers, controllers and electric door hardware). Bring them in before drywall on new construction, ask for one plan that covers every system, and insist on tested, labeled and documented cable.

1. What counts as low voltage

Low voltage work covers power-limited circuits, generally 50 volts or less. Line-voltage work (outlets, panels, lighting circuits) belongs to a licensed electrician. Many commercial projects need both trades; see our low voltage contractor vs. electrician guide for who does what.

System	What it includes	Typical cable
Data / structured cabling	Desk and wall drops, patch panels, racks, labeling	Cat6 or Cat6a copper
Backbone	Links between network rooms, floors and buildings	Fiber (sometimes Cat6a for short runs)
Wi-Fi	Access points on ceilings and walls	Cat6/Cat6a with PoE
Security cameras	IP cameras, NVR, viewing stations	Cat6 with PoE
Access control	Readers, controllers, electric strikes, maglocks, exit devices	Composite or multi-conductor cable plus Cat6
Voice, paging, AV	VoIP phones, overhead paging, displays	Cat6, speaker wire, HDMI-over-IP

2. Copper cabling: Cat6 vs. Cat6a

Commercial copper cabling follows the TIA-568 standard. The maximum horizontal channel is 100 meters (328 feet): up to 90 meters of solid cable in the walls (the permanent link) plus patch cords at each end. Any device farther than that from its network room needs a closer room, a fiber link or a switch in between.

	Cat6	Cat6a
Frequency	250 MHz	500 MHz
10 Gb/s distance	Up to about 55 m, depending on conditions	Full 100 m
Cable size	Smaller, easier in tight pathways	Thicker; fills trays and conduit faster
Good fit	Desks, phones, most cameras in existing offices	New builds, Wi-Fi 6E/7 access points, long runs, future 10 Gb/s

Both Cat6 and Cat6a carry Power over Ethernet, including high-power PoE (802.3bt). For larger PoE bundles, Cat6a and 23 AWG cable run cooler, which matters when dozens of powered cables share one pathway. Read our Cat6 vs. Cat6a guide for the cost side.

Plenum vs. riser

Cable jackets are rated for where they run. Plenum-rated cable (CMP) is required in air-handling spaces such as many drop-ceiling return plenums. Riser cable (CMR) is for vertical runs between floors. Using the wrong jacket is a common reason a building inspector fails a job.

Pathways and separation

Cable should be supported on J-hooks or tray, not laid on ceiling tiles, and kept away from fluorescent ballasts, motors and line-voltage wiring. Conduit stubs, low voltage mounting brackets and backboxes go in before drywall, which is why timing matters (section 9).

3. Fiber: when you need it and which kind

Fiber is used when copper's 100-meter limit is not enough, between buildings (no shared electrical ground and no lightning path), for backbone links between network rooms, and where there is heavy electrical interference.

Type	Where it fits	Notes
Single-mode (OS2, yellow jacket)	Between buildings, long campus runs, carrier hand-offs	Longest distance; optics have become inexpensive, so it is a common default for new backbone
Multimode OM3 / OM4 (aqua)	Inside one building, room-to-room backbone	10 Gb/s to about 300 m (OM3) or 400 m (OM4)
Multimode OM5 (lime)	Data center and short high-speed links	Rarely needed for a typical office

The common connector is LC; SC still appears on carrier equipment and older panels. Fiber is terminated by fusion splicing pigtails or with factory pre-terminated assemblies, then tested for loss. Outdoor runs need outside-plant rated cable, usually in conduit.

4. Network rooms: MDF, IDF and backbone

MDF (main distribution frame): the main network room where internet service enters and the core switch, firewall and servers or NVR live.
IDF (intermediate distribution frame): a smaller room or wall cabinet that serves an area within 90 m of cable. Large floors and warehouses often need one or more.
Backbone: fiber (or short Cat6a) from each IDF back to the MDF, usually in a star so one failed link only affects one area.
What a good room has: a rack or cabinet with patch panels and cable management, dedicated power and a UPS for PoE switches, ventilation, a lock, and every port labeled to match the floor plan.

5. Power over Ethernet budgets

Cameras, Wi-Fi access points, phones and many access control readers are powered by the switch. Each switch has a total PoE budget, and each port has a class limit.

Standard	Power at the switch port	Power at the device	Typical devices
802.3af (PoE)	15.4 W	12.95 W	Phones, basic cameras, readers
802.3at (PoE+)	30 W	25.5 W	Most Wi-Fi access points, PTZ-lite cameras
802.3bt Type 3	60 W	51 W	Wi-Fi 7 access points, heated cameras, some door hubs
802.3bt Type 4	90 W	71.3 W	Large PTZ cameras with heaters, displays

Add up the devices on each switch, leave headroom of roughly 20 to 30 percent, and put the switch on a UPS so cameras and door readers stay up during short power events.

6. Security cameras

Each IP camera gets its own home-run cable to a PoE switch; outdoor runs need outdoor-rated cable and a weatherproof junction box at the camera.
Storage depends on resolution, frame rate, motion versus continuous recording and how many days you must keep; decide retention first, then size the NVR.
Plan coverage by task: identify faces at entrances, overview in parking lots and warehouses, read plates only where a camera is placed for it.
Put cameras on their own VLAN so they are not reachable from guest Wi-Fi.

7. Access control: the electronic side of the door

A card or fob door has more parts than the reader on the wall:

Part	What it does
Reader	Reads the card, fob, phone or PIN
Controller / door hub	Decides who is allowed in, when, and logs every event
Electric strike	Replaces the strike plate in the frame; the existing lever lock stays, and free exit is mechanical
Maglock	An electromagnet that holds the door; needs a request-to-exit device and must release on fire alarm and power loss
Request-to-exit (REX)	Motion sensor or push button that tells the system a person is leaving, so it does not log a forced door
Door position switch	Reports door open, closed, held open or forced
Power supply	Powers locks, often with battery backup

Fail-safe vs. fail-secure: a fail-safe lock unlocks when power is lost; a fail-secure lock stays locked from the outside but always lets people out. Egress and fire code rules apply to every door, and the local building official (the authority having jurisdiction) has the final say, especially on maglocks.

Mechanical keys, cylinders and master key systems are locksmith work. The access control installer handles the readers, controllers, electric strikes, maglocks, exit devices and the cabling, and coordinates with your locksmith or door supplier when the hardware itself has to change.

8. Wi-Fi

Access points are placed from a site survey or floor-plan model, not by counting rooms. Warehouses with racking and metal need more planning than open offices.
Every access point should be cabled back to a PoE switch; wireless mesh is a fallback for places cable cannot reach.
Separate networks (VLANs) for staff, guests, cameras and building systems keep problems contained.

9. New construction and tenant improvements: timing

Phase	Low voltage work
Design	Drop counts per room, camera and door locations, network room size and power, pathway routes
Rough-in (walls open)	Backboxes, low voltage brackets, conduit stubs, sleeves through fire walls, cable pulled to rooms
After drywall and paint	Terminate jacks and patch panels, mount cameras, readers and access points, set up the rack
Before move-in	Test and label every cable, program switches, firewall, Wi-Fi, cameras and doors, hand over documentation

Missing rough-in is the most expensive mistake on a build-out: fishing cable through finished walls costs far more than pulling it while they are open.

10. Testing and documentation you should receive

A test result for every cable run (certification testing for warranty-grade jobs; at minimum a pass/fail verification).
Labels on both ends of every cable that match a floor plan or spreadsheet.
Fiber loss test results for every strand.
Network documentation: switch ports, VLANs, IP addresses and admin access handed to you, not kept only by the installer.

11. Questions to ask any low voltage contractor

Does your own crew pull the cable and run the fiber, or is it subcontracted?
Can you design cabling, cameras, access control and Wi-Fi as one plan?
Which camera and access control platforms do you install and support?
Who handles the electric door hardware, and how do you coordinate with our locksmith or door supplier?
What testing and documentation do we get at the end?
Who do we call after the job is done?

How XXL IT Services does it

XXL IT Services is a commercial low voltage contractor based in Meridian, serving Boise, Meridian, Nampa, Eagle and the rest of the Treasure Valley. Our own crew runs the Cat6, Cat6a and fiber, builds the network rack, and installs the switches, firewall and Wi-Fi. We are certified UniFi installers, install UniFi Protect cameras, and install access control with UniFi Access and PDK, including the electric door hardware. Commercial work only.

The Commercial Low Voltage Field Guide for Treasure Valley Businesses