Running a network out to a detached garage

October 12, 2026 · 5 min read · Josh Dargie · Markdown

Most of the detached garage questions I get arrive late. The trench is backfilled, the slab is poured, and the question has quietly changed from "how should we do this" to "can a wireless bridge make up the difference."

Sometimes it can. More often the honest answer involves renting a machine again in the spring.

The decision window here is unusually short. If there is an open trench between your house and your garage right now, everything below is cheaper this week than it will ever be again.

Wired or wireless, decided honestly

A point to point wireless link is a legitimate choice, not a cop-out. If you have clear line of sight, a short span and modest needs (a laptop, a couple of cameras, a speaker), it will work and it will keep working.

What you are accepting is that it is a radio. It needs power at both ends, firmware updates, and a mount that stays aimed after four winters. When it goes sideways on a Sunday, the troubleshooting is less obvious than "the cable is cut."

A buried cable is the thing you stop thinking about. That is the whole value proposition.

The split I use: if a trench is already being dug for power, go wired. If nobody is digging and nobody wants to, wireless is reasonable and you should stop feeling bad about it.

Fibre or copper

This is the decision people get wrong, and it is the one that costs equipment.

Copper between two separate buildings connects the electrical systems of those buildings through your data cable. The two structures do not share a ground reference the way two rooms do. A nearby strike, or even a decent surge on the pole, finds that path. I have seen the result often enough to recognise the pattern: dead switch ports at both ends, and the failure arrives in pairs.

Fibre is glass. It carries no current, so it carries no surge. Between buildings, that is the point.

Copper can be done properly, with bonding and surge protection at both ends, installed by someone who understands what they are protecting against. In practice, nobody owns that protection five years later. Fibre removes the question rather than managing it.

The other limit is distance. A copper run tops out around 100 metres, and that is the full path, including the climb up the wall, the slack in the ceiling and the trip around the garage to where the switch actually lives. A garage that measures 70 metres away on a site plan is closer to the limit than it looks.

If you go with fibre, buy single mode and buy more strands than you need. Put a small switch with an SFP port at each end instead of a bare media converter, and keep one spare patch cord and one spare transceiver in a drawer in the house. That drawer is worth more at 9pm in February than any amount of design work.

Conduit is the real decision

Direct burial cable works fine until the day you want to change something. Then it is a shovel.

Put conduit in the trench. Oversize it, use sweeping bends rather than tight corners, leave a pull string in it, and bring both ends up somewhere a person can actually reach. Label both ends. If the trench is open anyway, put in a second empty run, because the marginal cost right now is a length of pipe and ten minutes.

This is the same conduit rule I keep repeating for indoor work, and outdoors it matters more, since the alternative to a spare pipe is excavation.

Depth, separation from power conductors and permits are code questions, and they vary. Your electrician and your local authority decide those, not the person with the trencher.

Power decides what the network has to support

The size of the electrical feed out there is a networking decision, even though nobody frames it that way.

A single circuit gives you lights, a door opener and a small switch. A subpanel opens up heat, a compressor, an EV charger and a workshop that gets used in January. That changes the device count, the PoE budget and whether a small UPS in the garage is worth having.

Pick the mounting spot while the walls are open. Not on the floor, not buried in the ceiling above a car, and not in the path of sawdust. Garage air is dusty and cold, and gear out there ages faster than the same gear in a basement.

Plan for the garage you will have in three years

The drop count people ask for is almost always the drop count they need today.

What shows up later is predictable: a camera on the overhead door, an access point so the yard works, a door controller, a backup target deliberately kept out of the house, an EV charger that wants to report home, a workshop PC. None of that is exotic, and all of it wants a port.

Double whatever number you first wrote down. Ports are cheap while the walls are open, and the planning side of this is the same exercise as the pre-drywall checklist for the main house.

The season matters in Ontario

Trenching is a freeze-up decision. If the ground closes before the pipe is in, the real options narrow to waiting until spring or doing the cheap version along a fence line. The cheap version then becomes the permanent version, because nobody digs up a working cable.

If this is on your list for this year, it is a now item.

If you want a second set of eyes on a plan before the machine shows up, that is a short planning engagement, quoted as a fixed fee. My company RelayPoint Technologies (relaypoint.ca) does the install work in Southern Ontario if the cable still needs pulling. Either way, get in touch before the trench closes rather than after.

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