What is the best way to determine if a cable inside a computer is a data cable or power cable?

Answer 1

Per the A+ book "Guide to Managing and Maintaining your PC," it says to know for sure what type of cable you're dealing with, trace the cable from its source to its destination.

Generally, a power cable will be coming from the power supply unit, while data cables don't. That is the big block in one of the corners of the case, with the power switch and AC in on the outside of the case. Also, power cables' sockets will almost always be either rectangular, split into an even number of equally sized squares, or rectangular with one rounded corner and 4 metal pins, whereas data cables come in all shapes and sizes.

The easiest way is to check if the cable is coming from the power supply. Most of the time power wires are black (ground), red (5v), yellow (12v), and sometimes orange (3.3 v). Power cables are usually large gauge wires.

Data cables are usually flexes or fine gauge wires. Data are grey or black ribbon cables, for PATA. Small flat single color for SATA (commonly red or black).

Answer 2

Easy, just look at it!

Power cables almost exclusively have individually stranded multi-colored wires. Some may be sleeved for cable management. They end typically with a white 'molex' connector, usually 4-pin square or 4-pin long.

Data cables come in two forms: IDE Ribbon Cables, large flat grey cables, FDD ribbon cables, and SATA cables, red or orange 'small' cables that are slightly flat.

You may also have a very tiny 'audio' cable that goes from the CD-ROM to the motherboard.

There may also be USB Headers and Firewire headers, as well as speakers and LED lights. These carry both data and power, and are typically very small and bunched in the bottom right corner of your motherboard.

See your motherboard's documentation for picture diagrams!
Internal power cables are usually twin strand cables - coloured red & black. Data cables are normally flat, multi-strand ribbon cables coloured grey - with a red strand at one end to indicate polarization.

Answer 3

A very quick way, if the cables are already plugged in on both ends, is to follow it. If the cable ends up in a large metal block with one or two fans on it, which when you look at it on the outside of the case, leads out to an electrical outlet, it gives power to a part. If the other end goes to another part, the motherboard, a part on the motherboard, your disc drive, etc, etc, it's some form of communication cable.

Answer 4

Data cables are usually flat, either flat and about 3/8" (Sata) or flat and about 1 1/4" (floppy) or 1 1/2" (PATA).

Power cables are usually round, usually about 1/16" - 3/32", and are usually bundled with other cables.

Answer 5

The best way to determine that is to follow the cables. Data cables will lead back to the motherboard while power cables will lead back to the power supply.

A serial ATA hard drive power cable (often just a bundle of loose wires) will run from the hard drive with 5 wires typically 2 black 1 red 1 yellow and another wire (varies in color, mostly white or orange).

A serial data cable will be one cable with several wires inside and runs to the motherboard.

Answer 6

The best way to tell if a computer cable is a data cable or a power cable is to trace where it goes. If it comes out of the power supply, it is a power cable. If it goes between the motherboard or a peripheral card and a peripheral, then it is a data cable.

Answer 7

The most obvious and easy way would be to observe where the cable in question goes. If it comes out of the power supply unit, then it is a power cable. If it goes between the motherboard and some device that is not a fan, then it is a data cable.

Another way would most likely be to use an Oscilloscope to watch the signal. Otherwise you may be able to use a Multimeter. BE EXTREMELY CAREFUL! the contacts inside a computer are quite small and shorting the wrong wires could cause severe damage such as data corruption, or even the destruction of sensitive components.

Answer 8

If it comes from the power supply, it's a power cable. If not, it's a data one. Some data cables are flat and are joined in groups, they're also thinner than power ones.