High Ze on a TT system - help for a newbie please.....

[Inteificio]

Like .3 of a litre of fluid is going to make any difference?

Any tea served in a mug smaller than a pint is not worthy of an electrician.

 

[telectrix]

the only thing that should be served as a pint is beer.

 

[gazzamikes]

I was testing earth rod couple weeks ago at 463 ohms and rcd wouldn't trip couldn't work it out, rammed another rod in and it then started tripping albeit just inside the limit. But on my assessment he said 1660 is the max 200 is only an advisory

 

[Welchyboy]

These readings seem v high, maybe it's the soil type where you are, I'm in south east and even with a meter long skinny rod, the highest reading I've ever got is 86 ohms, it averages around 20/30 ohms, the best ever being 13 ohms, I usually try to install a 2 meter rod but have to cut it short sometimes as It will not go any deeper, I pilot it with a meter long 12mm sds bit first then use a paving mallet, been looking at the dewalt rod driver lately though!

 

[Engineer54]

These readings seem v high, maybe it's the soil type where you are, I'm in south east and even with a meter long skinny rod, the highest reading I've ever got is 86 ohms, it averages around 20/30 ohms, the best ever being 13 ohms, I usually try to install a 2 meter rod but have to cut it short sometimes as It will not go any deeper, I pilot it with a meter long 12mm sds bit first then use a paving mallet, been looking at the dewalt rod driver lately though!

I personally wouldn't go to the expense of a dedicated rod driver. A half decent SDS drill with a rotary off position will be more than adequate for the needs driving up to 3 X coupled 5/8'' 1m rods!! You can make your own, or purchase an SDS tool to fit the driving nut. Apart from anything else, using an SDS unit will give you an easier drive and far better results. Using a club/sledge hammer will have the rod springing and flexing all over the place, and ending up with the top of the rod sitting in a hole 10X the diameter of the rod ...lol!!

As i have stated many times now, the use of a single 1m rod of any diameter will in 99% of times leave you with an unstable rod. A rod needs depth to achieve stability....
You'll stand a far better chance of going down the full depth of 2X coupled if you stay well away from building external walls (at least 1 or 2m), ...as that's where you'll find all the old building rubble the original builder buried...lol!!!

 

[Welchyboy]

I personally wouldn't go to the expense of a dedicated rod driver. A half decent SDS drill with a rotary off position will be more than adequate for the needs driving up to 3 X coupled 5/8'' 1m rods!! You can make your own, or purchase an SDS tool to fit the driving nut. Apart from anything else, using an SDS unit will give you an easier drive and far better results. Using a club/sledge hammer will have the rod springing and flexing all over the place, and ending up with the top of the rod sitting in a hole 10X the diameter of the rod ...lol!!

As i have stated many times now, the use of a single 1m rod of any diameter will in 99% of times leave you with an unstable rod. A rod needs depth to achieve stability....
You'll stand a far better chance of going down the full depth of 2X coupled if you stay well away from building external walls (at least 1 or 2m), ...as that's where you'll find all the old building rubble the original builder buried...lol!!!

Will give that a try!!