Most enterprise Wi-Fi problems are determined before anyone plugs an Access Point (AP) in. AP Placement, what is between APs and client devices, switching and cabling have a tremendous impact. This is a plain-language guide to those physical decisions — enough to plan sensibly and to know when to bring in a professional RF design.
Scope: standard drywall office space with 10–12 foot ceilings. Warehouses, high ceilings, and large open areas follow different rules — more on those at the end. None of this replaces a proper predictive design and a validation survey for anything business-critical.
Capacity: more access points is not more Wi-Fi
A useful starting ratio for an office is one enterprise grade access point (AP) per ~40 active users, up to roughly 100 idle or light-use devices on an AP. Treat that as a planning figure, not a guarantee — it drops quickly with poor placement, poor configuration, or cheaper consumer-grade APs.
The counter-intuitive part: adding APs without an RF plan often reduces usable capacity. Wi-Fi is a shared medium. Every AP within earshot of another on the same channel competes for the same airtime, so a room full of access points can spend more of its time managing contention than moving data.
Channel width also has a major impact on performance and capacity. Wide 80 MHz channels produce great single-user speed-test numbers — one person, one AP, nothing else going on. Put more than about three APs in range of each other on 80 MHz and aggregate throughput, efficiency, and stability all fall. In a dense office space, narrower channels and more of them beat a handful of wide ones.
- Plan around ~40 active users per AP; derate for anything non-ideal.
- Enterprise-grade APs only — retail and ISP-supplied boxes don’t hold up under concurrency.
- Don’t solve a coverage or capacity problem by carpet-bombing the ceiling with APs.
- Reserve 80 MHz channels for sparse deployments; go narrower as density rises.
Fun Fact: In high capacity environments, wider channels will lead to less aggregate throughput as more clients/users log on. Four 20MHz channels are far more efficient than one 80MHz for aggregate capacity and throughput. Channel width selection can become a bit of an art, balancing individual throughput vs. user capacity and performance.
Placement: treat access points like lighting
The most reliable mental model for AP placement is a light bulb. Stand where the coverage needs to be and ask: if I put a light bulb where that AP is going, can everyone here see it? Anything that would cast a shadow — a full-height wall, a stack of shelving, a structural column, a mechanical unit — will cast shadows of differing darkness.
Obstruction distance matters too: the closer a blocker sits to the AP, the wider the shadow behind it. An AP tucked against a wall or wedged beside a duct is throwing away half its coverage before it starts.
- Drop ceilings: most enterprise APs mount straight to the grid — that’s the intended install.
- Exposed ceilings: bring the AP down to lighting height on all-thread and a junction box, or conduit — the same way security cameras are hung. Mounting directly to a high ceiling will create the illusion of good coverage while lowering capacity, and create poor cell boundaries leading to performance and roaming issues.
- Heavy-construction rooms: concrete, cinder block, stairwells, elevator shafts, and acoustically treated rooms usually need their own dedicated AP — signal won’t reach them from the hallway.
Cabling: one good run per access point
Each AP needs a single Cat 6 cable (Cat 5e will do, Cat 6 is preferred) carrying both data and Power over Ethernet. That run cannot exceed 100 metres end to end, and it has to terminate on a PoE-capable switch. Newer models can require beyond 30W (802.3bt), so ensure your AP model is not only matched to the PoE standard the switch is able to supply, but the aggregate power budget.
Two things bite people here. First, PoE budget: a switch rarely has enough power to run a device on every port at once, and the AP’s PoE class has to match what the switch can deliver — add up the draw of everything before you assume it fits. Second, the 100 metre limit shapes the whole layout: it dictates where intermediate switches have to live, and therefore where the cabling design needs fibre uplinks instead of copper.
- Cat 6, one run per AP, 100 m absolute maximum including patch leads.
- Size the switch’s total PoE budget for the real load, not the port count.
- Let the 100 m rule decide switch locations; use fibre for the links between them.
The supporting cast behind the SSID
A business network is a handful of appliances with distinct jobs. Small-business gear tends to fold them all into one box; at enterprise scale they separate out.
Firewall / gateway
The boundary between the internal network and the internet, and where the internet provider’s responsibility ends and yours begins. It handles NAT and traffic control, and often serves core services like DHCP and DNS. A home “router” is really just this piece, with minimal security, limited traffic control, and NAT that runs out of headroom under real user and application counts.
Router (often not a separate box)
The part that decides which path a packet takes to reach its destination. In most offices this function lives inside the firewall or the switches; dedicated routers show up mainly in service-provider, data-centre, and large-enterprise networks, where they also help contain a fault to a single switch or floor.
Switches
The last few metres of wired connectivity and power for APs, IP phones, and fixed devices. Switches link to each other and to the gateway over trunk links — fibre once a run passes ~30 m or needs 10 Gbps and up, Cat 6 for 1 Gbps inside 100 m (and for sub-30 m 10 G runs, though fibre is still the cleaner choice).
When to stop planning and bring in a specialist
The guidance above covers a conventional office. Get a professional predictive design and a validation survey when any of these are in play:
- Warehouses, high or open ceilings, or large open floor plates — these often need specialized antenna implementations.
- High-density spaces: auditoriums, training rooms, event or conference areas.
- Heavy construction throughout, or a lot of RF-hostile materials such as sheet metal, large racks, and physically dynamic environments that often change.
- Anything where the Wi-Fi is business-critical and downtime has significant costs associated.
A design planned on physics up front is far cheaper than re-cabling a ceiling after the fact.