Wiring Fundamentals: Shielded Cable
Shielded Cable
01.25
00:00 | - Shielded cable contains one or more internal core wires that are run within an outer conductive braided or foil sheath. |
00:07 | The internal core wires are insulated from one another and can be thought of as separate wires. |
00:13 | The conductive sheath they are within will absorb any transmitted electrical noise from a nearby electrical component and conduct it to ground before it can reach the core wires and interfere with the signal they're carrying. |
00:25 | To conduct any noise away, the shielded braid needs to be connected to ground, but it's critical that it's only grounded at one end. |
00:33 | As we talked about in the power grounding section of our wiring harness design, if the shielding braid is grounded at both ends it will almost certainly violate our star point earthing rules. |
00:43 | We use shielded cable for any particularly critical sensor inputs to the ECU. |
00:48 | Most notably engine speed and position signals are always run using shielded cable. |
00:53 | Other weak or low level signals that are particularly susceptible to electrical noise are also run using shielded cable, such as knock or exhaust gas thermocouple sensor signals. |
01:04 | As the sensor signals are almost always run back to the ECU, it's common for the shielding braids to be collected and grounded together at this end. |
01:13 | Your ECU may have a specific pin to connect these shielding braids to, or if not, they can be connected to one of your ECU's power ground wires. |