Quick Answer: 300 feet is 91.4 metres, which is 1.4 metres past the 90 metre permanent link limit and inside the 100 metre channel limit. It passes only if every patch cord in the channel adds up to 8.6 metres or less, and only if the run is certified. For a single device at 91 metres, the reliable options are a mid-span switch, a copper extender, or fibre with media converters. Expect 7 V of drop on a 0.6 A PoE load at that length, so plan power locally.
The number that governs the answer is 90, not 100. A permanent link is the cable from patch panel to outlet, capped at 90 metres; the channel adds the two patch cords and may reach 100 metres. A 300 foot reel used as a single run sits in the gap between those figures, which is why some installations certify and others fail insertion loss at 100 MHz.
Where 91.4 metres sits against the limits
Cat 6 is specified to 250 MHz over 100 metres of channel, and 10GBASE-T reaches 55 metres on Cat 6 and 100 metres on Cat 6a. At 91.4 metres, gigabit and 2.5GBASE-T are comfortable, 10GBASE-T on Cat 6 is not. Leave 3 dB of margin in the test result rather than accepting a pass at the limit, because temperature and bundle size move loss upwards.
| Option | Reach | PoE at the far end | Verdict |
|---|
| Single Cat 6 run | 91.4 m channel | yes, with 7 V drop | certify, do not assume |
| Coupler in the middle | not allowed | no | breaks the channel |
| Mid-span switch | 90 m + 90 m | yes, per port | best for several drops |
| Copper extender | 200 m at 100 Mbit/s | yes, at the transmitter | single legacy device |
| Fibre and converters | 300 m on OM3 | no, needs local power | long or noisy route |
Move the switch, not the cable
Mid-span switch
A small switch at the 45 metre point turns one impossible run into two legal ones and gives you a diagnostic point in the middle of the building. It needs a mains outlet and 30 W of budget, and it must be in a locked enclosure if the space is public.
Power at the far end
If the mid-span point has no power, a PoE-powered switch fed from the head end removes the outlet but adds its own draw: the upstream port then carries the switch plus the downstream device. Check the class sum before ordering, not after.
Fibre on the same route
Multimode at 91 metres
OM3 handles 10GBASE-SR to 300 metres and OM4 to 400, both far beyond the requirement, and the cable is 3 mm instead of 6 mm so an existing conduit takes it easily. Termination is the cost: two LC pairs and two converters per link.
Converter practicalities
Media converters need a socket at each end, add 0.5 W to 3 W of heat, and create an unmanaged device that nobody monitors. Where the far end already has a switch with an SFP slot, use that instead of a converter.
PoE voltage drop at 91 metres
Cat 6 at 23 AWG has about 6 ohm per conductor over 91.4 metres, so the loop is 12 ohm. At 0.6 A, which is a 30 W load, the drop is 7.2 V and the device sees 46 V instead of 53 V; at 0.3 A it is 3.6 V. Devices with a wide input range cope, cheap cameras with a 44 V floor reboot on cold mornings. A slimline ethernet cable at 28 AWG roughly doubles that resistance, so never use it for a powered run of this length.
Practical scenarios
Related reading on this site: ethernet cable, ethernet cable vs phone cable cover the same link from the connector and the cable side.
- Situation: one camera at the far corner of a warehouse, 91 metres from the closet – fit a mid-span PoE switch at 40 metres rather than an extender, so the second half is a normal certified link.
- Situation: a 300 ft reel already pulled to a reception desk – certify it with 3 metre patch cords at both ends and record the result, since 91.4 plus 6 metres stays inside the channel.
- Situation: an access point drawing 25 W at 88 metres – use 23 AWG Cat 6 and a 54 V supply, because 0.5 A over that loop loses about 6 V.
- Situation: a run through a lift shaft with VFD cable – fibre, or shielded Cat 6a bonded at both ends; a foil screen that is only earthed at one end will not stop the noise.
FAQ
Can a 300 ft cable be used as a patch lead?
Technically it works, but a 91 metre patch cord leaves no allowance for the permanent link and cannot be certified as part of a channel. Use it as the fixed run and keep the cords short.
Does 300 ft support 10GBASE-T?
On Cat 6, no: the standard stops at 55 metres for 10GBASE-T. On Cat 6a, 91 metres is inside the 100 metre limit, provided alien crosstalk is controlled and the installation is tested to 500 MHz.
Which jacket rating is needed indoors?
In the US, a riser run between floors needs CMR and a plenum ceiling needs CMP, both listed as CL2 or better under NEC. A run in conduit inside a wall can use CM, but check the local code before the cable is ordered.
