Low-voltage contractor or IT company: who should run your cable?

The short answer: either can run the cable; what matters is where their job ends

In Dallas, office network cable is installed by two kinds of vendor. A low-voltage contractor is a construction trade: they pull cable for data, phones, cameras, door access and audio-visual, and their job ends when the cable is terminated and tested. An IT company sets up and supports the network, computers and phones, and most IT companies do not run cable at all; they arrive after someone else has.

I am the third option, and it is less common than it should be: an IT company that also does the cabling. I run Cat6 for new commercial construction and renovation across Dallas, from the IT room to each drop, terminate and test it, and then install and configure the rack, switch, firewall and access points that go on the end of it. For a typical professional office, that means one company, with me as the contact, is responsible for the cable, the network and the support afterwards.

This article lays out what each vendor does, who installs ethernet drops in a commercial office, how voice and data cabling works today, how the tenant improvement process decides who does the work, and when a low-voltage crew is honestly the better choice. If you are comparing bids right now, send me the plans and I will tell you where mine would differ.

What does a low-voltage contractor actually do?

"Low voltage" is a construction term for anything that carries a signal rather than power for lights and outlets. In an office build-out, that covers data cable, telephone cable, security camera cable, door access wiring, speakers and displays, and sometimes the fire alarm wiring, which is a separately regulated specialty. The low-voltage contractor is one of the subcontractors the general contractor brings in, alongside the electrician and the HVAC crew.

On the data side, a low-voltage contractor typically:

• Runs Cat6 (or whatever the spec calls for) from the telecom room to each jack location shown on the drawings.
• Installs the supports in the ceiling, the boxes and faceplates at the wall, and the patch panel and rack in the telecom room.
• Terminates, labels and tests each run, and provides test results.
• Pulls fiber between telecom rooms on larger jobs.

What they generally do not do: supply or configure the switch, firewall or access points, set up the internet circuit, connect any computers or phones, or come back after the project is closed out. Their scope ends at the patch panel, and they are usually working from a drawing that was done before the tenant knew where the desks would go. Good low-voltage contractors do this work well and fast, especially on large jobs with big crews. The limitation is not their quality; it is where their responsibility stops.

What does an IT company do, and why do most of them not run cable?

An IT company is responsible for the things that make the office work: the switch and firewall in the rack, the Wi-Fi, the internet circuit, the computers, the phone system, the email and file systems, and the support afterwards. Most IT companies are not set up to run cable. It is physical construction work, it needs ladders, lifts, ceiling access and a relationship with the general contractor, and it happens on a construction schedule rather than a business one. So the typical IT company arrives after the cable is in, plugs its equipment into someone else's patch panel, and hopes the labels match the wall.

That handoff is where offices lose time and money. The IT company inherits a rack it did not build, drop locations it did not choose, and test results it did not see. When something is wrong, the cabling contractor has closed out the job and the IT company has no way to know whether the fault is in the wall or in the rack. I describe what that looks like on move-in day in cabling and IT support from one company.

I chose to do the cabling myself precisely because of that handoff. When I run the cable, I already know what will plug into each drop, I place the access point drops where the coverage walkthrough says they should go, I put the telecom room where the network needs it, and I test each run against the equipment it will serve rather than against a generic pass. The cable and the network are designed together, by the same person, once.

Low-voltage contractor vs IT company vs both: side by side

Here is the comparison in one place. The third column is how I work; the first two are how the market usually works.

The pattern is clear. A low-voltage contractor and a typical IT company each cover half of the table, and the half they do not cover is the other one's job. That is fine on a large project with a project manager coordinating both. For a small or mid-sized office, there usually is no project manager, and the tenant becomes the coordinator by default.

Who installs ethernet drops in a commercial office in Dallas?

It depends on when in the life of the office you are asking. There are three common situations:

1. A new build-out or renovation. The general contractor usually includes a low-voltage subcontractor in the bid, working from the architect's telecom drawings. You can accept that, or you can ask for data cabling to be carved out of the general contractor's scope and done by your own vendor. Landlords and contractors are used to this request.
2. Adding drops to an existing, occupied office. This is not a construction project, and the general contractor is long gone. You hire a cabling vendor directly. This is a very common job for me: a new desk, a printer that moved, a conference room display, a few access points, a camera. Often done after hours in a few hours.
3. A single drop or a repair. Some low-voltage contractors have a minimum job size and will not come out for one drop. I do, because it is usually part of a bigger support relationship.

Whichever situation you are in, the person installing the drop needs to know three things: where the telecom room is, whether the ceiling is a plenum (a return-air space that requires plenum-rated cable), and what the building requires for work in the ceiling. Some Dallas buildings require after-hours work, notice to the property manager, or specific firestopping where cable passes through rated walls. I ask those questions before quoting so the number is right the first time. For the cost side, what structured cabling costs for a Dallas office explains per-drop pricing and what moves it.

Voice and data cabling: why it is one cable now

"Voice and data" is a phrase left over from when phones and computers needed different wiring. Older offices have a separate telephone cable to each desk, often Cat3, running back to a punch-down block in the closet where the phone company's lines arrived. Data ran on Cat5 or Cat6 to a patch panel. Two systems, two contractors, two sets of labels.

Today, business phones are almost always VoIP: the phone is a network device that plugs into a Cat6 jack and gets its power through the cable from the switch. There is no separate voice wiring. A modern office is cabled with Cat6 to every location, and any jack can serve a phone, a computer, a printer or an access point depending on what you plug in. That is why I recommend two drops per desk: one for the computer, one for the phone, both the same cable.

A few things still deserve a separate thought:

• Analog lines. Fax machines, some alarm panels and elevator phones may still need a traditional line. Those are rare and are usually handled at the demarcation point rather than cabled to every desk.
• Phone system choice. If the phones are hosted in the cloud, the office needs a good internet circuit and a firewall that prioritises voice traffic, which is a network setting, not a cabling one.
• Power. Phones get power from the switch, so the switch needs enough Power over Ethernet budget and should sit on a battery backup so the phones keep working through a short outage.

Because I handle both computers and phones, the voice side is designed into the cabling plan rather than added later. I work with Cleod 9 Voice for hosted phone systems and set the network up to carry calls cleanly.

Structured cabling for tenant improvements: how the process decides who does the work

A tenant improvement, or TI, is the build-out of a leased space to suit the new tenant, usually paid for partly by a landlord allowance. The process has a few features that decide who ends up running your cable, and it is worth understanding them before the lease is signed.

• The general contractor's scope. The landlord or the tenant hires a general contractor, whose bid normally includes low-voltage cabling as a line item. If you say nothing, their subcontractor runs your cable from the architect's drawing.
• The carve-out. You can ask for data cabling to be excluded from the general contractor's scope and done by your vendor. Do it early, in writing, and ask them to keep the ceiling open along the main cable path and in the telecom room until the cable is in.
• The allowance. Ask the landlord's representative whether cabling done by your own vendor is an eligible allowance expense. It commonly is, as long as it is invoiced and documented properly.
• Building requirements. The property manager may require after-hours work, notice, escorted access, specific firestopping, and paperwork from every trade before anyone works in the ceiling. Ask for the building's rules for vendors and pass them to whoever is doing the cable.
• The schedule. Cable goes in after framing and before drywall and ceiling tile. Miss that window and every drop costs more.

On a TI I join at the plan stage, mark the drops and access points, place the telecom room, order the internet circuit, and run the cable in the framing window. Then the rack, network and equipment follow the construction schedule through to move-in. The office move and new office IT setup page covers the same process when you are also leaving an old space.

When a low-voltage contractor is honestly the better choice

I would rather you hire the right vendor than hire me for the wrong job. A low-voltage contractor with a crew is the better choice when:

• The pull is very large. Several hundred drops across multiple floors on a tight construction schedule needs a crew of several people, lifts and a dedicated foreman. That is more than a small company pulls in the window. On jobs like that I am more useful designing the network, specifying the cable plan, checking the test results and building the rack and equipment, with the crew doing the pull.
• Fire alarm or life-safety wiring is involved. Those systems are separately regulated and belong with the specialists who do them every day.
• The job is mainly security or audio-visual integration with a large camera system, access control across many doors, or a boardroom full of displays and microphones. I run the cable and put those devices on the right network, but a specialist integrator installs and programs the systems themselves.
• There is no IT relationship at all. If the tenant has an in-house IT department that will build the network, a low-voltage contractor working to that department's specification is the natural fit.

For the usual Dallas professional office, the law firm, the dental practice, the insurance agency, the design studio, with a few to a few dozen people and no IT staff, the whole job fits one small company, and having the same company be your ongoing IT support is what makes the office work on day one and stay working.

Questions to ask whoever runs your cable

Whether you talk to a low-voltage contractor, an IT company or me, these questions sort out a good cabling job from a cheap one:

1. Where does your work end? At the patch panel, at a configured switch, or at a working desk?
2. Is the cable plenum-rated if the ceiling is a plenum? Using riser cable in a plenum is a code problem.
3. Will each run be tested, and will I receive the results?
4. How will the runs be labeled, and will the labels match at the wall, the panel and the documentation?
5. Is Cat6 the spec, and if you are recommending Cat6a or fiber, what is the reason? See Cat6 vs Cat6a vs fiber for what actually matters.
6. What is not included? Rack, patch panel hardware, patch cords, core drilling, firestopping, lift rental, after-hours labor.
7. What do you need from the building and the general contractor, and have you worked in buildings with those rules before?
8. Who do I call if a desk is dead a month after move-in?

That last question is the whole article in one line. If the answer is "the other company", you have found the seam. If the answer is a name and a phone number, you have found your vendor. Mine is on the contact page, and I answer it myself.

Questions people ask

Written and reviewed by

Anthony Omini, founder of Cross River Tech

Over 15 years in IT across many industries, now running Cross River Tech, a small owner-led managed IT company in Dallas. Every article is written from his own client work and checked by him before it is published.

Not sure who should run your cable? Send me the plans or the address. I will tell you honestly whether the job fits my company, and quote the cable and the network together if it does.

Ask Anthony(214) 612-7080About Anthony