Caravan hook ups

[TJ Anderson]

Firstly, you dont test between the rod and the earth.

Cheers

Did you used to be on SF Forum a few years back?? Mr S

 

[GEOFF S]

Did you used to be on SF Forum a few years back?? Mr S

No, ive only visited one other forum and not a regular, a newbie really.

Cheers

 

[TJ Anderson]

No, ive only visited one other forum and not a regular, a newbie really.

Cheers

I suppose it was 7 or 8 years ago now. There was a particular member on there, extremely funny IMO, but he always signed off every post with "Cheers". lol

 

[Engineer54]

I might have been miss reading this situation, if you are loop testing this single rod with everything disconnected and seeing a Ra value of 4 to 5 ohms, then that's fine. I was under the impression that you were seeing this low Ra value when testing at the hook-up points, with the rod disconnected.

As for testing between the TNC-S and the rod, not sure why you tested this, but all sorts of reasons for this value to be seen, one remote possible reason is the local DNO TNC-S multiple N-E link earth rod location. It could well be quite close-by, especially if the DNO's supply to this caravan park is derived from an overhead supply...

 

[Doomed]

I might have been miss reading this situation, if you are loop testing this single rod with everything disconnected and seeing a Ra value of 4 to 5 ohms, then that's fine. Yep, thats how it is. I was under the impression that you were seeing this low Ra value when testing at the hook-up points, with the rod disconnected. No, these readings were around the same value give or take a few ohms

As for testing between the TNC-S and the rod, not sure why you tested this, I was checking that there was a physical seperation between them, I took a reading between them first before stripping lots of stuff out of the way to confirm visually that there was no connection. but all sorts of reasons for this value to be seen, one remote possible reason is the local DNO TNC-S multiple N-E link earth rod location. It could well be quite close-by, especially if the DNO's supply to this caravan park is derived from an overhead supply...

Thank you

 

[Doomed]

Firstly, you dont test between the rod and the earth.

Cheers

Normally I wouldn't, but as the readings I was getting seemed too good to be true I was measuring to see if there was a connection between the TNCS earthing and the TT earthing before I stripped loads of stuff down to confirm a physical disconnection.

 

[GEOFF S]

Normally I wouldn't, but as the readings I was getting seemed too good to be true I was measuring to see if there was a connection between the TNCS earthing and the TT earthing before I stripped loads of stuff down to confirm a physical disconnection.

Okay, that makes sense now. Well this is one of those times when a really low RA can be problematic in the sense of PME diverted neutral currents.

Have you disconnected the swa earths then tested one by on to see if a particular ciircuit is low?

Cheers

 

[Doomed]

Okay, that makes sense now. Well this is one of those times when a really low RA can be problematic in the sense of PME diverted neutral currents.

Have you disconnected the swa earths then tested one by on to see if a particular ciircuit is low?

Cheers

That would be difficult in this situation, and as I could visually confirm the separation I have left it. I would of liked to of investigated further but it would of been an academic exercise to satisfy my curiosity, and time constraints did not allow this.

 

[GEOFF S]

That would be difficult in this situation, and as I could visually confirm the separation I have left it. I would of liked to of investigated further but it would of been an academic exercise to satisfy my curiosity, and time constraints did not allow this.

Well if the armour is the cpc, i was thinking there could be a risk of corrosion to exposed armouring/glands.

Cheers