2006-10-03 23:55:06 · 14 answers · asked by messiah 1 in Consumer Electronics ➔ Other - Electronics
I'll guess that you are referring to an outer METAL sheath ?
If so it has a number of uses :
1/ Grounding
2/ Prevention of induced stray RF / EMI interference
3 / Drain wire
It also provides a tough sheath to prevent vermin from chewing thru into the main wires
2006-10-04 00:09:14 · answer #1 · answered by Perry 4 · 0⤊ 0⤋
The outer sheath of an electric cable is either rubber or plastic. Bit are non conductors of electricity. Hence, when you have negative and positive cables twined together, they do not connect up and cause a short circuit (where -ve and +ve get connected without passing through a device (registor)).
Secondly, imagine what would happen if you touched the cable without the sheaths. Simple... you would get a shock. :)
At times, you have a separate sheath covering the sheathed cables. This is to hold them together. The angles of twists are maintained.
2006-10-04 00:05:21 · answer #2 · answered by bedraj 2 · 0⤊ 0⤋
The purpose of the outer sheath is to protect from electrocution and to keep the wires uniformally together. You can get a "double insulated" cable which is used specifically outdoors and contains an inner and outer sheath, this is to give added protection against any possibility of water ingress.
2006-10-04 00:06:38 · answer #3 · answered by iainb31 2 · 0⤊ 0⤋
Vinyl or carbon are for electrical shock protection
Metallic (covered with outer PVC) are for creating a magnetic shield to protect inner wires from receiving unwanted or unsolicited frequencies that could disturb the signal carried by the live wires inside.
2006-10-06 22:04:52 · answer #4 · answered by Sweet Dragon 5 · 0⤊ 0⤋
the outermost sheath is to water proof the cable and prevent electrical shock, inner sheaths are to bundle the wires into cable and insulate them from eath other (preventing a short) and to water proof again.
2006-10-04 00:03:01 · answer #5 · answered by afsm666 3 · 0⤊ 0⤋
If it was only an inner sheath all your wires would be on the outside and fall apart.
2006-10-04 09:40:15 · answer #6 · answered by veg_rose 6 · 0⤊ 0⤋
As well as the reasons mentioned above, it's also a way of making cables with a single colour, since the live, neutral and earth wires inside are all different colours.
2006-10-04 02:00:43 · answer #7 · answered by Dramafreak 3 · 0⤊ 0⤋
To protect the insulation on the conductors from abrasions and other damage, There are many different kinds of sheaths, from simple pvc to multi layered steel wire armoured, copper, aluminium, fireproof, Low smoke, flameproof, and so on..
2006-10-04 00:06:02 · answer #8 · answered by jayktee96 7 · 0⤊ 0⤋
It stops the inner sheaths falling apart.
2006-10-03 23:59:45 · answer #9 · answered by Gerard McCarthy 2 · 0⤊ 0⤋
As well as all the above, it stops the inner wires from being pinched or bent too severely, as this would cause heat and could be a danger
2006-10-04 00:01:19 · answer #10 · answered by ukcliffhanger 1 · 0⤊ 0⤋