- Reaction score
- 14
At the sub feeder panel I have a reading of 0.15 on L1 & L2 and on L3 a reading of 0.16 ohms at the start of the circuit off the 50A MCCB.
System in TN-S
At the CDP the reading is bouncing between the following
L1 0.6 to .88, L2 0.68 to 0.8 and L3 0.62 to 0.78 ohms. but remains at 0.15 at the feed end. This is causing the readings on the radials to be between 1 and 4.08 ohms Zs. So pass and fail dependent when you hit the test button!!!
The distance is 97m, 35mm 4core SWA with the SWA used as the earth return. The cable is incassed in concreat along parts of its route and is under the main sewer pipe for about 30m too.
R1 + R2 is high for this length of run at just below 0.8 ohms.
IR readings are all greater than 500Mohms between all conductors and the conductors and the SWA.
All nuts / bolds / screws have all been cleaned off and re tightened.
Glands replaces paint ground off, bango's bolted through the body with 25mm pig tails used and the Incrediable Hulk hired to re tighten everything.
But the results at the CDP are still bouncing all over the place.
So my reasoning is that there is a joint somewhere along the line that is failing, but then the result would be just high not bounching all over the place.
Note: 4 different test meters have been used (Fluke 1652/3) and all show the reading going all over the place.
Other than replacing the SWA and adding an additional earth.... what is the cause and another solution please?
System in TN-S
At the CDP the reading is bouncing between the following
L1 0.6 to .88, L2 0.68 to 0.8 and L3 0.62 to 0.78 ohms. but remains at 0.15 at the feed end. This is causing the readings on the radials to be between 1 and 4.08 ohms Zs. So pass and fail dependent when you hit the test button!!!
The distance is 97m, 35mm 4core SWA with the SWA used as the earth return. The cable is incassed in concreat along parts of its route and is under the main sewer pipe for about 30m too.
R1 + R2 is high for this length of run at just below 0.8 ohms.
IR readings are all greater than 500Mohms between all conductors and the conductors and the SWA.
All nuts / bolds / screws have all been cleaned off and re tightened.
Glands replaces paint ground off, bango's bolted through the body with 25mm pig tails used and the Incrediable Hulk hired to re tighten everything.
But the results at the CDP are still bouncing all over the place.
So my reasoning is that there is a joint somewhere along the line that is failing, but then the result would be just high not bounching all over the place.
Note: 4 different test meters have been used (Fluke 1652/3) and all show the reading going all over the place.
Other than replacing the SWA and adding an additional earth.... what is the cause and another solution please?