Todays Earth Rod Efforts

[uksparks]

Hi,

As I mentioned last night, I was going to be putting the earth rods in for this summer house this morning.

I put 8 rods in, this was one stack of two, and two stacks of three rods.

The readings from the two that were 3 rods deep were around 10 Ohms per location, and the two rod stack was approx 17 Ohms.

I tested the first rod at approx 10 Ohms, then connected the second rod to the first which was 17 Ohms which them reduced the total down to approx 6 Ohms, then connected the third rod which was 3 deep and that bought it down to 3.2 Ohms.

So the Ra that I achieved today was a respectable 3.2 Ohms

All rods were connected together with 16mm earth.

I am going to go back next week and bang in another couple of piles of two rods so another four in total because I want to get that sub 1 Ohm reading.

Anyway, what do you think, 3.2 is not bad is it!!


Reading from first rod: 10.6 Ohms (3x 4ft 5/8" Rods)


Reading from second rod: 17.2 Ohms (2x 4ft 5/8" Rods)


Reading from third rod: 9.6 Ohms (3x 4ft 5/8" Rods)


Reading from first and second rod combined: 6.3 Ohms


Reading from all three rods connected together: 3.2 Ohms

 

[uksparks]

I'd need an SDS max bit wouldn't I? and I could rent a drill to do it, presumably an SDS max drill would do it or would I need something bigger?

 

[Corbs]

I could try putting another on the top of them, I could do with someone holding the rod so i can hold the hammer with two hands.[/QUOTE]


you tried something like this? might help

[video=youtube;0sLv4LLVPbA]https://www.youtube.com/watch?v=0sLv4LLVPbA[/video]

 

[Corbs]

I'd need an SDS max bit wouldn't I? and I could rent a drill to do it, presumably an SDS max drill would do it or would I need something bigger?

thats fine, prob normal sds would do but might take longer, but vid below is sds max demolition hammer

[video=youtube;VJYhHZYu_4g]https://www.youtube.com/watch?v=VJYhHZYu_4g[/video]

 

[uksparks]

Thats not a bad idea.

 

[telectrix]

i just get glennsparks to come round and snarl at the rod. the rod then drives itself in.:uhoh2:

 

[NDG Elecs]

I'd need an SDS max bit wouldn't I? and I could rent a drill to do it, presumably an SDS max drill would do it or would I need something bigger?

I got a cheap SDS Max from screwfix for a ton and bought a Bosch rod driver to go with it. The rod driver was bloody expensive but it has all paid for itself already. Only gripe is the last few TTs with crap Ra have all had PME upgrades available, so the kit is sat gathering dust!

I tried using an SDS plus to drive rods in; a lump hammer is better IMO. At least til your forearm starts to look like Popeye's that is.

 

[Deleted member 72666]

I could try putting another on the top of them, I could do with someone holding the rod so i can hold the hammer with two hands.

or one of these much easier

[video=youtube;vvCZvNj8H30]https://www.youtube.com/watch?v=vvCZvNj8H30[/video][/QUOTE]
That seemed to go in easy.......Is that house built on a swamp?

 

[Lucien Nunes]

And here's a Kango Model C doing the same thing in 1935. Of course in those days power tools were run direct from the mains without isolating transformers, and had metal cases and class 1 construction. So as the notice says on the side, it's important to earth the tool reliably (via the brown wire which was the proper colour then). But if the rod's not in yet...

I haven't driven any rods with my Model C but I have used it to dig up fence post footings and knock a wall down.

 

[PEG]

I've got a similar looking Wolf,bit later vintage,and for some unknown reason,we always ended up using it for boring holes through crossing timbers and telegraph poles...no clutch and lots of motor inertia,so when it went self-aware,it did so for ages...

There is nothing like getting continued service,from vintage gear,i think it is why i started collecting anvils...and it's catching...my protege has just recond a 1948 Atco mower,with a kick-start Villiers,and mowed his sisters' lawn with it. :yes:

 

[tomspark93]

Interesting read, I wonder how many people would have been happy with a reading between 100-200 ohms...

Just out out of interest, how come you decided to tt the summer house?

 

[IzzyS]

Who is paying for this experiment?

 

[uksparks]

Interesting read, I wonder how many people would have been happy with a reading between 100-200 ohms...

Just out out of interest, how come you decided to tt the summer house?

I TT'd it for two reasons, one is that its a TNCS supply and taking it 70m down the garden in my opinion is not going to fall within what I would call extending the zone within a sensible distance that I would be happy with, plus to TT it, the cost involved in that is not that much different to an extra core of 16mm x 70m.

Inside the main house, everything should be at equal potential, but down the garden its a bit unknown, and stuff will be plugged in and taken into the garden too.

Think about it this way, if you loose your neutral in the suppliers TNCS supply, your exported / exntended earth to the summerhouse has just been lost / removed, then you are left with an earth that is going to act as a return neutral for the supply, so if you were touching a piece of class I equipment and loose the neutral, then you will become part of the circuit and get a shock (more than likely).

The customer is also looking at connecting a hot tub off the summerhouse, and feel it would probably be best to use a TT at the remote end due to the slim chance of loosing a neutral in the DNO TNCS supply as any metal work would rise to 230v, and as they have a number of class I fittings going into the summerhouse, like lights around the outside, and appliaces within, then I feel a low Ra with a nest of rods would be better. It would't take much to come into contact with true earth when stepping out a hot tub.

Who is paying for this experiment?

its not an experiment, yet I do feel like I am wanting to better the reading down to a very good figure at less than 1 ohm. The time spent on the earthing im not charging for as will be making enough out of the install of the summerhouse.

 

[tomspark93]

Justified answer and good job! Keep us updated on any progress it'll be interesting to see how low you can get it.

 

[Spearmint]

It's nice to see someone putting all that effort in to make it a decent TT install.

 

[OtexElectrical]

Good work