Cat 5 Ampacity

Introduction

Ethernet cable is a common type of cable - it is CAT 5 or 6 cable. It typically comes in 4 pairs, but is also available in 12 or more.

http://www.sumidacrossing.org/LayoutElectricity/MRRWire/WireAmpacity/ - says AWG 24 carries 3.5A open and 2A enclosed.

From Stefan H

Under the following assumptions up to 3A should be fine.

1. 26AWG cat5/6 cable
2. using two leads
3. cable is relatively short
4. normal ambient temps
5. stepper control (at most use 75% of configured drive current)

Also: https://en.wikipedia.org/wiki/American_wire_gauge

Charts

• This chart suggests about 1.8A for 8 core wire 23 AWG- [1]. Useful chart in terms of differentiating between the number of cores, but does not consider free air vs enclosed
• 23 AWG, .7A - [2].Why the 100% difference betweeen different charts?
• This chart shows free air and derating for bundles, which most approximates open air Cat 5 (8 bundle) - here 23 AWG is 7A*.7 = 5A

Notes

Change on CEB controller: using RJ45 for power-over-cat5. That is a great standard for easy connection, as 8 leads are rated for a total of 16 amps enclosed, and 28 Amps open. So a good product ecology standard for all electrical signal/power transmission in CNC and controls applications. The relevance is the cost and easy connection in prototyping.

We could potentially even consider power over cat 5 for scalable power supplies - such as 8 cat 5 wires get you to a 200A welder - which would be the first use I hear of power electronics over cat 5. I think it's worthwhile because cat 5 is ubiquitously available. Phone burial feeder cable can also be used with Cat 5 ends, no?cc

From Oliver

• https://en.wikipedia.org/wiki/Power_over_Ethernet#Standards_development

"Each pair of twisted pairs will need to handle a current of up to 600 mA (Type 3) or 960 mA (Type 4)."

Thats what a pair can handle (in the new upcoming 4PPoE standard), means per wire about 300 mA to 480 mA.

Sourcing

• Cat6, 23 gauge, 19 cents per foot, 300v rating. [3]
• 22 ga - [4] exists
• Sourcing - 1000 feet for $200 - [5]
• 12 pair 22 awg exists, but is 10x more expensive than 4 pair - [6], so 3x more expensive for the same service.
• 22 ga 8 conductor unshielded cable - [7]
• Belden stranded - 24 cents/foot - [8]
• 100 feet stranded shielded 8 conductor - $38 - [9]
• 16 cents per foot, unshielded - 22-8C CMP Plenum - [10]

Higher Pairs

• 12 pair, 24 ga, CAT 3 solid - [11] - 73 cents/foot
• 25 pair, 25 ga, CAT 3 solid - $1.29 - [12]

Links

• Cat 5 Cable
• Direct Burial Cat 6
• Cat 6 Direct Burial Shielded Cable