Cable management for a desk you are building
Retrofitting cable routing onto a finished desk means working upside down in the dark with a drill you cannot swing. Doing it while the top is still on sawhorses takes about an hour. The only hard part is deciding the layout before you commit holes.
This is a woodworking problem with an electrical subject. The decisions are about hole sizes, fixings and clearances.
Grommets: size them for the plug, not the cable
The mistake that forces a second hole: sizing the opening to the cable diameter. You will eventually need to pass a connector through — a USB-C end is small, a DisplayPort or HDMI head is not, and a power brick certainly is not.
2 in. — two or three cables, no large connectors
2-1/2 to 3 in. — the usual choice; passes display and power connectors
3-1/2 in. and up — needed if a power brick or a hub must pass through
Cut with a hole saw or a Forstner bit. Back the exit side with a sacrificial
board to stop the breakout, which on veneered MDF is unforgiving.
Position matters more than size. The natural instinct is to centre the grommet behind the monitor, which puts it exactly where a monitor arm clamp wants to go. Offset it four to six inches to one side.
And keep it off the back edge if the desk will ever sit against a wall with a skirting board — the gap that creates is usually enough to route behind without a hole at all.
The tray
A tray under the top does two things: it gets the mass of adapters off the floor, and it gives every cable a defined path so nothing hangs in tension.
Mount it toward the back, leaving at least 4 in. of clearance behind your knees at the deepest point of the chair's travel. A tray mounted too far forward is the single most common complaint about a desk someone built themselves, and it is discovered after the finish is on.
A shop-made tray is a shallow plywood box screwed up into the underside, or a pair of rails with a mesh panel between them. Neither needs to be pretty. It needs to be open on the long sides so you can drop a cable in without threading it.
Service loop, which is where sit-stand desks are different
On a fixed desk, slack is a convenience. On a height-adjustable desk it is the thing that decides whether the desk destroys its own cables.
Every cable that runs from the top to something on the floor changes length through the full travel of the frame. If it is tight at the top, it pulls at every raise. If it is loose at the bottom, it loops into the mechanism.
typical frame travel — about 25 in. (roughly 26 to 51 in.)
required slack — travel, plus routing length, plus 4 to 6 in. margin
So a cable reaching the floor needs roughly 30 in. of take-up somewhere in its run.
Two ways to absorb it. A vertical cable chain or spine fixed to the frame takes the loop and keeps it ordered, which is the tidy answer. Or you hang a deliberate loop from the tray and let it open and close, which is free and works as long as nothing can catch it.
What does not work is a cable run straight and tight. It will fail at the connector, and it will fail at the desk end, where the strain concentrates.
The number that makes this manageable: minimise how many cables reach the floor at all. One power lead to a strip mounted on the frame, and everything else plugged into that strip, turns a dozen travelling cables into one.
Fixing to the underside
Screws into the underside of a top are the one place this becomes a woodworking failure rather than an inconvenience.
- Measure your screw against the top thickness. A 3/4 in. top takes a 1/2 in. screw. This is obvious and it is still how people put a dimple through a finished surface.
- In MDF, pilot everything. MDF splits along the face when a screw goes in dry near an edge, and the split is invisible from above until the finish cracks over it.
- Use the apron where there is one. If the top has a rail underneath, fix the tray to the rail rather than the panel. More material, and it does not load the span.
That last point connects to the other decision: anything heavy hung from the middle of an unsupported top adds to the load that makes it dip. A power brick weighs little, but a tray full of them sitting at mid-span is load in the worst place — see what actually sags.
Order of work
2. drill grommets with the top still accessible, backed to stop breakout
3. fit the tray before the top goes on the frame
4. mount the power strip to the frame, not the floor
5. route, then set the slack with the desk at its lowest position
6. raise it fully and check nothing goes tight
Step five is the one that gets reversed. Set the loops at full height and everything looks tidy until the desk comes down and the slack has nowhere to go.