CAT5 SOLID vs. STRANDED RJ45 CONNECTORS AND PoE
There is NOTHING more annoying than wasting time debugging a network problem only to find
it was the cable or connector. Badly made connections or incorrect cabling is a foolish thing to
spend time on - do it once and do it right. This guide may help you eliminate most CAT5 cabling
problems.
RJ45 Connections - Some things to be aware of
We get emails and phone calls stating, "I had the radios working for a week and now they will
not stay connected. I think I have a bad radio." 99% of the time it is the connection to the
radios, not the radios.
1. The RJ45 connector is the critical connection - always use the highest quality connectors
as well as the correct connectors (SOLID center conductor’s connectors on solid
center conductor wire). The most common cause of connection faults are bad
connectors. There are different connectors for STRANDED and SOLID cable and
manufacturers do not always do a good job at differentiating them. Spend the time to
make sure you have the right connector type. If you use the wrong type of connector the
cable may or may not work initially but it will almost certainly fail very quickly.
2. Make and test practice cables until you get it right every time - especially before you
destroy a cable you just spend 2 hours fitting.
3. When cutting the exterior cover of the cable be very careful not to cut the insulation
cover of the conductors since this can cause shorts - bottom line: the cable won't work.
4. Expose a maximum of 1 inch of individual conductors when preparing the cable for
connection.
5. Line up all the conductors according to the wiring standard you are using.
6. Measure the cable and trim the conductor ends so they are are all the same length and
no individual conductor wire is visible outside the plastic cover of the RJ45 connector.
7. Carefully slide the prepared cable into the RJ45 connector making sure the end of the
conductors reaches the end of the RJ45 connector.
8. Using the crimp tool make the connection using one firm squeeze operation.
9. Test the cable before fitting if possible.
HD Communications Corp.
2180 Fifth Avenue, Ronkonkoma, NY 11779
Tel: (631) 588-3877 Fax: (631) 588-3879 E-mail: techs@hdcom.com Web: www.hdwifi.com
Solid core Cable vs. Stranded Cable
UTP CAT5E cable comes in two forms, SOLID or STRANDED. SOLID refers to the fact that
each internal conductor is made up of a single (solid!) wire and MAY be required for Power-overEthernet (PoE) if the cable run is more than 50 feet., STRANDED means that each conductor is
made up of multiple smaller wires. STRANDED cable (patch cables) have a smaller 'bendradius' (you can squeeze the cable round tighter corners with lower loss) and due to its flexibility
should be used where you plug and unplug the cable frequently. All other things being equal the
performance of both types of cable is the same with the exception of long run (PoE) as noted
above. In general, SOLID cable is used for long long runs (typically backbone wiring)
and STRANDED (patch cables) for short runs typically PC to wall jack. Again, beware; each type
of wire, SOLID or STRANDED, needs its own connector type. We offer both SOLID CAT5E
Outdoor CAT5E cable. See our website for more details. Also see our website for premade STRANDED CAT5E patch cables for indoor short run applications.
Again, connectors are designed differently for SOLID core than for STRANDED. Use of a
connector with the wrong cable type is likely to lead to unreliable cabling and a failed
connection. Plugs designed for SOLID and STRANDED core are readily available, and some
vendors even offer plugs designed for use with both types. The punch-down blocks on patchpanel and wall port jacks are designed for use with SOLID core cable only. See our website to
find our SOLID center conductor connectors.
PoE over CAT5 Cable
For all outdoor PoE applications it is recommended to use only CAT5E cable that
is UV-protected with SOLID 24 AWG conductors. If available, shielded cable which can
safely carry 360 mA at 50 V according to the latest TIA ruling is acceptable. The cable has eight
conductors (only half of which are used for power) and therefore the absolute maximum power
transmitted using direct current (DC) is 50 Vdc (Typical PoE injectors are 48 Vdc out) × 0.360 A
× 2 = 36 Watts. Considering the voltage drop after 328 ft (100 meters), a PoE enabled device
would be able to receive 31.6 W, however most standard PoE switches and PoE injectors are
14.5 Watts so for very long runs over 200 ft one should consider PoE injectors that are higher
than 14.5 Watts if the device you are connecting requires more than 9.5 Watts. See our website.
This is a guide and you should check with each manufacturers requirements as there are many
non IEEE802.3af PoE compliant enabled devices on the market that require different
voltages, higher currents, and even different pin outs and the use of a IEEE802.3af
PoE compliant PoE injector or IEEE802.3af PoE compliant switch can cause damage to the
device you are connecting it to as well a an unsafe condition.
HD Communications Corp.
2180 Fifth Avenue, Ronkonkoma, NY 11779
Tel: (631) 588-3877 Fax: (631) 588-3879 E-mail: techs@hdcom.com Web: www.hdwifi.com