Discussion and questions related to the course Practical Motorsport Wiring - Professional Level
I'm about to start a harness where I'll be sending 4 shielded cables through a bulkhead connector (cam, crank, 2x knock). Ordinarily I'd just pass each shield through an individual pin and pick up back up again on the other side. The problem is that the pin count is seriously stretched and 4 shield pins is a huge waste.
Is there any reason I can't splice all 4 shields together on either side and pass them through a single pin? They all end up spliced at the ECU into a single shield ground pin anyway. I can't think of a logical reason it would make any difference, it just kind of feels wrong.
How far away is the ECU from the bulkhead connector? if it's only a meter or so, I would think one shield would be fine. If it's 3-4 meters, I would probably upside the bulkhead connector to have separate shields
The ECU is about 1.5m from the connector. It's already a 61pin item. I'm unaware of a larger one. I can get away with it currently (zero spare pins) but it would be nice to have room for another analogue signal or two for future proofing.
Thanks for the reply!
So, I'm assuming you are using a AS 24-61 with 61 #20 pins? Can you use #22 pins -- if so, the popular 20-35 is a smaller connector with 79 pins, or consider splitting your bulkhead connector into two connectors, like a 20-39 (2 #16, and 37 #20), combined with a 18-32 with 32 #20 pins.
I'd overlooked the 79pin option. Thanks. I think in this case splitting it over two connectors would probably be a slightly nicer in the long run though.
Although I have never personally seen it done in a motorsport loom, I cant come up with any reason why slicing all the sheilds to a single pin would be an issue. I have seen some military control systems where all shields connect to a single point in the body/backshell of the connector so that is effectively a similar scenario.
I mentioned it to a fellow local harness builder yesterday and he said he's always just used a single shield pin and never had it cause him a single issue.
Found a pic of what I mean:
That would certainly make dealing with individual shielded cables much tidier. No need to sleeve join the braiding.