Earth Loop Impedance Tester

[pwdrive]

As promised, these pictures were taken a few minutes ago, using the new gizzmo testing the earth loop impedance at the chalet using the ground rod I put in, the other day I reported an impedance of 65 ohms, today's test shows it's gone down:

       

Lawrence.

[Radio Fixer]

Aren't you supposed to pee around the ground rod a few time

Gary

[ppppenguin]

Earth rods can benefit from being watered:
http://www.pinkfishmedia.net/forum/archi...41378.html

In the early days of radio when sets needed aerial and earth connections there wer possibly apocryphal stories of people earthing their radio to a potted plant. It's hard to google this for references as all you get is various green fingery sorts of links.

[pwdrive]

I've been peeing in that location for years Gary, one of the freedoms of living out in the sticks.


The two different readings I got on different days might be due to a couple of things, 1st, the rods interface to the mass of the earth might be settling in, 2nd the tester as supplied at the moment can only do the test from a ring or spur outlet socket, the plug/socket contact resistance might have changed between the two tests, they do an IEC lead with test probes to fit that unit so's the test can be done at the phase/neutral/MET at the consumer unit, might get that lead at some point if I can scrape up some cash

Lawrence.

[pwdrive]

Marconite's the stuff these days apparently.

Lawrence.

[ppppenguin]

The plug/socket resistance is unlikely to have changed that much. I'd worry if that was measured in ohms rather than fractions of an ohm though with dirty pins and contacts you can get poor readings. I'd reckon on ordinary day to day changes in soil wetness.

All the specialist earthing kit you ever wanted:
http://www.steeplejack.co.uk/Store/Default.aspx

[pwdrive]

That's what I reckon too, anyways, went over to my mates sawmill today to help set up a jig for making some A frames for a special shed order. took the tester with me as he ask if I could test his earth, the sawmill is in the woods by a river, inside and outside is damp, lots of old sawdust, spiders webs everywhere.

There's two supplies, one is 3 phase from his own 100KVA generator, the other is single phase from the DNO, that feeds an open side covered work area and also an old porta-cabin (the office) that's where I plugged in the tester as soon as the test cycle started the RCD tripped out, reset the trip and tried again, same thing happened, the tester I think uses about half the normal RCD trip current so far as I know, I have done several test in the chalet and the house without any tripping, he might have a few ma leakage to earth to start off with and maybe the tester provided the rest.

I looked at the main incomer to the henly type block, L&N in L&N out to the meter, no earth provision at that block so it lookks TT, didn't have time to investigate further but he did say that the earth cable to the rod was secured to the rod with a jubilee clip about 20 years ago and had not been touched since, it's all very damp at the sawmill, might look into it further on another visit.

Lawrence.

[AlanBeckett]

I looked at the main incomer to the henly type block, L&N in L&N out to the meter, no earth provision at that block so it lookks TT, didn't have time to investigate further but he did say that the earth cable to the rod was secured to the rod with a jubilee clip about 20 years ago and had not been touched since, it's all very damp at the sawmill, might look into it further on another visit.

Take some Wellies and thick Rubber Gloves.
Alan

[pwdrive]

I'll glue me wellies to a couple of beer crates as well....I'll go careful, I won't be posting any pics of the electrics at the sawmill as they'll look to scary, I remember the traveling fairs in the 50' and 60's.

Lawrence.

[AlanBeckett]

We've all done it.
SWMBO used to keep a Horse at a Farm where he milled Barley every day. Closed shed, lots of Dust, ordinary 3-Phase Motors. etc, etc.
I maintained a very low profile.
Fortunately the right/wrong combination of events don't happen very often, and everything being wet is a distinct advantage.
Stay clear when it dries out in the Summer.

Alan