Two weeks ago, we searched for ground loops on BSC6. We found some but we will really chase them after the cartridge installation due to the limited accessibility of the ISI on its stand at EY.

The ISI cabling drawing is D0901301.

At the feedthroughs, we realized that the pin 13 of the 25pin connectors were grounded (except T240 2 and 3 - Need to be rechecked). It seems the grounding is realized by the pods (see LLO alog 2822) We have to wait the cartridge installation to do measurements on our pods.
At the interface chassis, only the pin13 of the L4C 2-3 cables are grounded.

We opened 4 connetors on both ends of 2 in-air cables (L4C 1 and 3)

L4C - 1 cable (grounded at one end (by the pod)):
At the feedthrough connector: the back-shell is not connected to the shield and pin 13 is disconnected.
At the interface chassis connector: the back-shell is connected to the shield and pin 13 is disconnected

L4C - 3 cable (grounded on both ends - pods and chassis)
At the feedthrough connector: The back-shell is not connected to the shield and pin 13 is connected to the shield
At the interface chassis: The back-shell is not connected to the shield and pin 13 is connected to the shield.

The in-air cables are not identical (CPS in air cables used for the geophones? That's would explain why gender changers were installed).
If the shields are grounded at the pod:
- At the interface chassis, pin 13 should not be connected and the back-shell should not be connected to the shield
- At the feedthroughs, the shield should be connected to the pin 13 and the back-shell shouldn't be connected to the shield