- Reaction score
- 422
Hi,
This link might give some ideas. https://www.wbdg.org/FFC/NAVFAC/DMMHNAV/hdbk419a_vol1.pdf
This link might give some ideas. https://www.wbdg.org/FFC/NAVFAC/DMMHNAV/hdbk419a_vol1.pdf
Discuss Advice Wanted - VERY High Earth Resistance Problem in the UK Electrical Forum area at ElectriciansForums.net
Hi,
This link might give some ideas. https://www.wbdg.org/FFC/NAVFAC/DMMHNAV/hdbk419a_vol1.pdf
0.74ohms can't be going through the earth surely, did you touch the water supply pipe on the way down and are going back to the network via someone else's bonding?I’d look at burying tape rather than rods and create an Earth nest.
I got a c asking Ra last week even with all the sun we’ve had.
I didn't install it, only tested it, it's been in the ground 15 years.0.74ohms can't be going through the earth surely, did you touch the water supply pipe on the way down and are going back to the network via someone else's bonding?
0.74ohms can't be going through the earth surely, did you touch the water supply pipe on the way down and are going back to the network via someone else's bonding?
I assumed he wasn't t testing a substation just a normal rod, but i did add a "surely", to account for the fact that it could be some crazy setup for amateur radio or somethingWhy can’t that be going through the earth? The DNOs regularly achieve Ra lower than that for substations
Got to page 403 then gave up
Cool, go back when you've had a couple of days rain and test again, just out of curiosity.Managed to get it down to 112 Ohms, after paying out a small fortune, 3 earth rods later all connected with flat copper tape (25mm x 3mm x 25m) dug into the ground about 12” deep, couldn’t get any deeper due to roots and rock. Thanks guys for the advice
1667 is only relevant to circuit/s downstream of RCD/s.Am I missing something ? Why the need for such low readings, gn3 anything under 250 ohms is acceptable but in theory fine up to 1667 book not to hand so may be wrong?
Agree with you the 1667, but if over 200ohms it is deemed unstable or words to that effect.Am I missing something ? Why the need for such low readings, gn3 anything under 250 ohms is acceptable but in theory fine up to 1667 book not to hand so may be wrong?
Earth Rods are being hit in to their entire length, approx 1m deep, cannot get much deeper as we are hitting bedrook, have tested using |KEW-5105A and then tried removing the earth rood and testing again 1 meter further away from the property and so on, but cannot get the reading to get any lower. The soil is not the best, looks as though its had about 100 years of tiles, bricks and plaster pored into it.
In a case like this, the readings will be identical for all practical purposes.Sounds to me you are doing loop testing not Ra testing(?)
In a case like this, the readings will be identical for all practical purposes.
Can you really say that? Ra testing would only be between the rod he has installed which he said was 1M down and 10 meters away while the loop test will be the Ra plus the full loop.
An Ra test is a dead test and a loop test is a live one.
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