Max Ze for TT system

[Guest 004]

To measure an earth rod, you need a 3 or 4 lead tester, depending on the make, one lead is attached to the rod, then the other leads are attached to twigs, er sorry probes which are then placed in the ground at given distances from the rod. Any connection's to installation would need to be disconnected.

 

[spark 68]

We can use an EFLI tester, this gives enough accuracy on the side of caution to measure this.

Granted you may need a proper tester for the installations of generators and the like on some larger industrial sites, you can also use stakeless testers now as well.

 

[Guest 004]

Indeed, quite a few methods to measure, and if the rod has already been tested, then a loop at a socket with a calculation is fine.

 

[Engineer54]

15 mins to check your rods? Why?

I suppose you want your ra values.

You would have checked them before? Why don't you just plug in a metre into a socket and loop it, then do your rcd tests?

2 mins max. Which leaves you 13 mins dig your metre out.


Maybe in you're world everything is prepared and all you do is push the button, doesn't quite work like that in the real world though!!


Insanity: doing the same thing over and over again and expecting different results.
Albert Einstein


Which all goes to show, just how little you know about TT systems!!

To measure an earth rod, you need a 3 or 4 lead tester, depending on the make, one lead is attached to the rod, then the other leads are attached to twigs, er sorry probes which are then placed in the ground at given distances from the rod. Any connection's to installation would need to be disconnected. ​

And is exactly the method i use as i have an open field to the back of my property, so i have the distance to obtain accurate measurements... I'd like to see you hook that little lot up and conduct the tests in 3 mins!! ...lol!!

Engineer54 a "working" earth what the hell is that? Us electricians call it a stable or un stable earth.

Stability is an important factor, but a working TT system (earth) is one that is as near TN values as you can possibly get, and not one, that you'd probably be happy with, by following the BGB!!

I think most Engineers, especially those that are site based HAVE to live in the real world, and probably more so than the average jobbing electrician. Responsibility comes with a price when you get it Wrong, as even some small errors, can end up costing the client or the contractor (or both)some pretty serious money!!

 

[Guest 004]

I think a serious waste of money is trying to acheive TN values on a TT system.

 

[D Skelton]

It is often the opposite though. What would you do if you had a 200A supply or more?

 

[spark 68]

I think a serious waste of money is trying to acheive TN values on a TT system.

Depends entirely on the site, it may be well be cost effective and desirable on large projects to achieve TN values from a TT system, the cost savings of not needing RCDs alone would make it worth while (not talking about final circuits here), using TNC-S and PMEing such a large project may also have massive cost implications, and may not be an option based on cost grounds, this could be down to the size of the bonding conductors, or it may simply be not allowed at all for one reason or another, likewise TN-S may also have huge costs attached.

This is where E54 is perfectly correct, but I also tend to fit in the other camp where domestic is concerned, that is I try to get it as low as is reasonably practicable, but see little point in over engineering it past say two rods driven deeply, if I can get it reasonably low (below tens of ohms) and stable I am usually happy.

 

[Guest 004]

Which all goes to show, just how little you know about TT systems!!

I have worked extensively on TT systems and tested them, both in the UK (LUL) and South East Asia

 

[D Skelton]

Very confused as to why Eng isn't biting anymore?! Has the wriggler stopped wriggling? Is he just chilling with the rest of the fish?

 

[pepparz]

hes probably had enough, gone insane and been sectioned.

 

[Engineer54]

I have worked extensively on TT systems and tested them, both in the UK (LUL) and South East Asia
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You could have fooled me with the statements you come out with above!!!

 

[Engineer54]

Very confused as to why Eng isn't biting anymore?! Has the wriggler stopped wriggling? Is he just chilling with the rest of the fish?

Can't be asrsed basically, too busy clearing up my desk and looking forward to my vacation!! lol!!

 

[Engineer54]

hes probably had enough, gone insane and been sectioned.

Can't leave it alone can you!! One thing i can assre you of, and that's, that you'll be sanctioned long before it's my turn!!

 

[Guest 004]

Can't be asrsed basically, too busy clearing up my desk and looking forward to my vacation!! lol!!

Still at your desk, cleared mine last Friday , and not going back for 6 weeks. Now enjoying glorious sunshine in my TT abode in SE Asia.

Sorry couldn't resist.

 

[sparks1234]

Can't be asrsed basically, too busy clearing up my desk and looking forward to my vacation!! lol!!

Ahha, so there we have it E54 is a paper shuffler and not in the real world….LOL