Hi guy's.
We are in serious need of direction.
We have installed an installation of a MRI, GE is installing a 80kva ups and the magnets .
They are complaining of floating neutral from 0.2 ohms to 0 6 ohms that is fro N to E bar.
Below is the earth loop impedance that we got.
Cable is a 95mm x 4 core ecc
Main C/B is 250 amp 37ka.
Main cable is 95mm x 4 core ecc 75 meters
Red white blue
0.16 ohms 0.14 ohms 0.08 ohms
5.72 ka 1.42 ka 1.69 ka
234 volt 232 volt 230 volt
N to E bar is 0.215 volt.
N to E bar is 0.2 to 0.6 ohms.
E Continuity is 0.01 ohms.
All readings are good.
And.
Mini-sub to MLVP.
mini-sub has a 450 amp 20 ka C/B.
Main cable is 120mm x 4 core in parallel 80 meters
Red white blue
0.8 ohms 0.06 ohms 0.07 ohms
3.28 ka 3.08 ka 1.89 ka
234 volt 232 volt 230 volt
N to E bar is 0.1 volt
N to E bar is 0.00 ohms
E continuity is 1.13 ohms ( not good )

Do you think our problem is because of the mini-sub earth continuity which should be less than 0.02 ohms that we are having a floating neutral.
Although all is looking good but there is an issue
Has anyone out there have some advice