Really low Ze from earth rod!

[Engineer54]

I personally can't see how a single 1m rod of any size can give a value that low... To measure your Ra value, the rods earthing conductor is tested in isolation to any other earthing conductors, bonding conductors or CPC's...

Maybe a rod driven into ground that's been soaked with effluent for many years (such as on a farm) may give a lower value, but then the electrode isn't going to last too long at all, unless it's made of a high grade Stainless Steel... lol!!

I wonder how many electricians just lately have been thinking that they've done well with values they have obtained, mainly due to driving a rod into water sodden soil?? Perhaps they all ought to go back and check again after a dry period!! The truth is, if they have only driven in a single rod, the chances are that the TT system they were so proud of, has risen in value by many ten's of Ohms and in all probably is'nt even stable....

 

[SPARTYKUS]

We'll find out soon when Luke reports back!

 

[MKS]

Rise Park, Top Valley, Bulwell Hall, Bulwell, quality!!!

 

[SPARTYKUS]

Victoria centre. Big fair (goose fair). Hyson green, beeston

 

[MKS]

Vic will look special once the upgrade is complete!!! Westfield, the owners, usually do a quality job! Some of their big centres in Oz are quality and they did a sterling job of the old Eagle centre in Derby! Broadmarsh needs rebuilding! Currently in Lace Market which I don't mind, but right next to some god awful flats filled with all sorts!!!

 

[MKS]

I was not around when the Tram system was built, but since it runs back end of the Green, Goose fair has lost some impact! :-(

 

[SPARTYKUS]

Sorry to luke the OP, gone off topic. MKS, good chap! Grew up on Rise Park.

 

[MKS]

Grew up in Snapewood! And concur on apology :-(

 

[LukeBuckaz]

Thanks for your replies folks, and thanks for not ripping me to shreds as it was my first earth rod installation. I will be sure to re-test when I go back in a couple of weeks.

 

[Toby Kuhnert]

I got an Ra of 17.6ohms from a single 1.2m 3/8" rod the other week. Do the 5/8" rods come pre-threaded for the coupler, or do you have to thread the rods?

 

[Geordie Spark]

Please be gentle...

...now I installed my first earth rod on saturday! I was expecting a really high Ze as up to 200ohms is allowed by BS7671. My Ze was 0.34. Does this seem odd to anyone that has done one/many before?

Engineer 54 will be doing handstands & cartwheels when he reads this one !!! :biggrinjester:


edit: oops ..... I've just found E54's post

 

[Engineer54]

I got an Ra of 17.6ohms from a single 1.2m 3/8" rod the other week. Do the 5/8" rods come pre-threaded for the coupler, or do you have to thread the rods?

Exactly as i thought, ....perhaps you should read this taken from post 41 on this thread

I wonder how many electricians just lately have been thinking that they've done well with values they have obtained, mainly due to driving a rod into water sodden soil?? Perhaps they all ought to go back and check again after a dry period!! The truth is, if they have only driven in a single rod, the chances are that the TT system they were so proud of, has risen in value by many ten's of Ohms and in all probably won't be stable....

 

[somersetsparks]

I got an Ra of 17.6ohms from a single 1.2m 3/8" rod the other week. Do the 5/8" rods come pre-threaded for the coupler, or do you have to thread the rods?

The rods we get come as just plain threaded rods, you can buy couplers, pointy ends for driving and beating ends for.. well beating!