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Grounding question!

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LAN_403

Killa-X

Sun May 17 2009, 10:15PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

I own a 4ft rod that I picked up from a hobby store. It's music wire, and it's 4mm diameter. I cannot drill it because it just destroys my drill bits and even cut 1cm off my last one when i thought it was drilling. Not a mark. So i looked it up, and music wire is suppose High tension carbonized steel. Really strong shit that's made to hold tons of force. So, Can I just simply wrap say 3 inches of stripped wire around it and hammer it into the ground? I cant drill a hole in it without killing bits so i have a terminal. What else is there to do!

Cesiumsponge

Sun May 17 2009, 10:32PM

Registered Member #397 Joined: Wed Apr 19 2006, 12:56AM
Location: Western Washington
Posts: 125

You can drill hardened steel, but it requires drill bits and grind geometries that not available at consumer hardware stores like Home Depot. Wrapping wire around it wouldn't be good enough unless you have some sort of clamping system to clamp the wire coil around the rod itself. You don't want resistance to gradually increase as the surfaces oxidize. You can get a fairly good idea how to fabricate one by looking up images of "grounding clamps" on the Internet. In fact, there hardware store might have a grounding clamp that would work for you, saving some fabrication efforts. Treat it with some corrosion inhibiting paste for electrical contacts and you should be good to go.

I'm not sure how well steel works as a grounding rod since copper is ideal. It's better than nothing I suppose. Someone more knowledgeable might chime in on the performance gap between copper and steel as a grounding rod.

MinorityCarrier

Sun May 17 2009, 10:45PM

Registered Member #2123 Joined: Sat May 16 2009, 03:10AM
Location: Bend, Oregon
Posts: 312

Livestock/farming fencing supply stores carry grounding posts for use with hot-wire fence HV supplies.

CesiumSponge is correct about the clamping approach to attaching a wire to the post. That is the most reliable way.

For electronic equipment, sometime a thick-walled Cu-alloy perforated pipe filled with hygroscopic salts is used to maintain good contact with earth where soil moistrue is not that great.

Killa-X

Sun May 17 2009, 11:44PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

What if i bench-grind around the rod so its more a ) ( shape, stripe a stranded wire and put it around the ) ( shape? That way the wire is on the freshly sliced metal that is more in the core...

Cesiumsponge

Mon May 18 2009, 01:11AM

Registered Member #397 Joined: Wed Apr 19 2006, 12:56AM
Location: Western Washington
Posts: 125

You really need to clamp it on there. Wrapping a coil of wire around something won't fasten it securely because it'll untension a certain amount the second you stop winding, unless you wrap the coil around a slightly smaller diameter coilform, then press fit it onto your grounding rod. A grounding clamp should be less than $5, I am sure you can find any manner of non-grounding clamps like pipe hangers and pipe clamps which would work just as well at the hardware store with some imagination...anything to mechanically fasten your wire against the ground rod.

Sulaiman

Mon May 18 2009, 07:35PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

If you really MUST drill it then heat the part for the hole to red heat and let it cool slowly. This will anneal the steel (from memory)

What is the Earth connection for?

Safety - Use the Utility company Earth, MUCH lower resistance than a simple rod.
Also, come to the very worst, less legal liability.

RF - A very large topic ! Generally wires laid out over a wide area; with or without earth rods; on, below or above(best) the ground.

Lightning - Good Luck !

Killa-X

Mon May 18 2009, 11:53PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

It was for RF, but I've been told to just use a rod and hammer it into the ground to fix RF (tesla coil) i mean, currently my tesla was grounded through a railroad track (toy train) 3ft into the ground. My tesla coil did work, and I manage to get tiny streamers considering it was a first test. I wonder if a Tungsten drill bit would do the job...Too bad I dont own one but i know where to buy one

Considering how fast i oddly killed my mosfet, i decided to just go SSTC.

I can run my mosfet for over 5 mins with a rotary sparkgap and leyden jar. Once you add the tesla coil, few mins, i shot the mosfet. So, I put a metal can above the mosfet, snubber, and diode bridge. Fully cased with metal, grounded it through the outside 3-ft track, and it STILL died. I have no TVS diodes at this time, and its being triggered by pin 3 (16V) 10ohm resistor. My power supply is 16V for the 555 (18V max) and last i checked, IRFP460 (500V 20A) can go up to 50V i THINK...

Anyways, yes, this is for RF grounding outside my window, under our deck. And it's a slope, constant shade, so it's usually wet. Considering it's michigan here and water table is maybe 30ft due to my area... but i cant say that for sure. All I know is the soil under my deck will be wet for awhile due to the down hill slant and shade.

HV Enthusiast

Tue May 19 2009, 11:21AM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Forget the steel 4mm rod. Go to your local Lowes or Home Depot and buy a "real" grounding rod (copper coated) and grounding rod clamp. Will cost you about $10.00.

Proud Mary

Tue May 19 2009, 01:53PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Just put some clamps on it, lad - like Terry clips - or U-bolts if you want it done up really hard.

Arcstarter

Tue May 19 2009, 04:22PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Steel is definitely more resistive than copper. Make a primary for a Tesla coil out of steel, and you will see what i mean -.-. But for this, i do not think a bit of resistance will hurt. After all, it is a small coil. Also, i am sure the wire will have plenty of resistance, he will have to use 10's of feet of rather thin wire, if i understood him correctly.

Here is something you CAN do. Get two bolts a bit longer than the thickness of your rod (at least), and cut two pieces of metal from something like that VCR. Drill two holes on the sides of the metal, and put the screws through the two, put the nuts on, put some wire on the rod and clamp it down. That was very vague, but i think you understand.

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