EIB TP gegen UTP kabel

[drzni]

Hi.
Entschuldigung ob Ich in english schreiben aber menie deutch ist nicht zehr gut.

I am writteing a seminar for school about EIB.
When I was writteng about used comunication media I mentioned that common use is, so called EIB Twisted Pair (TP). He asked me, why not useing UTP cable, wich is also TP and has 4 pairs and is chiper then EIB TP.
I explained him tha EIB TP is used also for power supplay of EIB devices and the main request is to ensure at least 21 V at the end of the line (300 - 750m) and EIB TP is tested to ensure that request.
He sead that probably UTP can ensure the same request.
Is he right, or should I told him any other reasons why useing EIB TP and not UTP cable.
Thank you for your comments.
Miha

[klaus407]

Hi Miha,
I think the main reason for the standard is the insulation of the cable. As it can run in the same conduits as 230 V cables it has to fulfil the same insulation standards.

[tweky]

EIB Cabel (TP1) need a 0,8mm2 CU
and
UTP Cabel is a 0,6mm2 CU

EIB standart says:
The EIB Cabel must be have min. 0,8mm2!!

[Gaston]

Hi all,

Just back from Holliday. UTP STP is not a single king of canble, so it has nothing to do with th esection of the cable (i.e. 0.6 or 0.8mm2), you can have both in UTP and STP, and of course other sections too.

I don't know which grad e of schooö we are speaking about, bacause if it is a a non technical school the teacher may not really know what he's talking about :D , or it may be a pitfall question ;)

In fact EIB cable ist UTP !!!! More precisely it is S/UTP (Screened UTP).

STP and UTP do not report to the outer screen areounf the cables but the shield around each pair ! So you can have:

UTP: Unshielded Twisted Pair: No shield, no schreen, only twisted pair cables in a protection (sheath).

S/UTP: Screened UTP, as UTP but there is a metal foil around the whole bunch of twisted pair cables (This is the case for EIB).

STP: Shielded Twisted Pair: Each pair of twisted cables are shielded !!!

S/STP: Screened STP, like S/UTP but with STP

This is the theory, but usually in practice, speaking of UTP or STP, one really most often mean S/UTP and S/STP especially when speking of network.

Regarding TP cables there are quite a lot of figures which charaterieze th ecorrect cable. For EIB the most importents are:


2.5kV AC isolation for 5 minutes
4kV AC isolation for 5 minutes
800V isolation between cores
Resitance: 20-75 Ohm/km
min 5 twists/mNow the specified cable fitting all requirements (those above and others) is a S/UTP cable. The screen itself is not important for EIB and is NOT connected for EIB operation (there exist some rare exceptions to this rule however). Since th escreen is not connected it is a S/UTP cable used as UTP cable to be precise.

Best regards,
Gaston