How to Check Ohms Resistance

The intent of your grounding for your equipment is standard and usually mandatory (depending on your location in the world). You would normally, however, connect your Cable B to the equipment source (service equipment). Cable A would be terminated (bonded) to the grounding bar in your service equipment. There would be one grounding lead to the ground field/pit where you would have more than one ground rod (again, dependent on your location and the type of installation).

You don't necessarily want to run two separate ground leads from the same piece of equipment. That may result in unintended fault paths and an unsafe condition.

There are many ways this would need to be done based on the type of equipment you are grounding, in what environment it serves, they type of power delivered to the unit, etc...many different aspects.

What is the model of clamp on meter you are using? Do you want to check the resistance of your grid using a fall potential type of setup, or are you trying to determine the actual resistance of your grounding method (where you would megger out the grounding leads)?

Clamp meters (when used as clamp-ons) do not utilize probes/leads. They are clamped around conductors/wires.

ETCR2100C+ Earth Resistance Clamp Meter----ISO,CE,OEM,RS232

Wow, I don't know where to start. AS CP said, clamp meters don't have probes, and I am not familiar with Earth Clamp meters. An ordinary Ohm meter has probes. It will read close to zero with them shorted. With no other cables attached to your machine, connect one probe to the metal frame, and the other to the copper ground rod. This will give you the resistance between the new rod and the ground from the power cord (green wire) which is connected to the metal frame. Now that you have the number, connect the new copper rod to the metal frame to enhance the ground connection of the power cord ground.

ETCR2100C+ Earth Resistance Clamp Meter----ISO,CE,OEM,RS232

A clamp meter measures current(Amps) not resistance(ohms) although some clamp meters have built in voltmeters and ohmmeters. The resistance that you are going to measure on the installation you describe will probably be less than a normal ohmmeter can read and to determine how effective the ground rod is two ground rods will be required. Normally dry soil is sometimes a poor conductor, so if your good ground connection is important you might also consider keeping the soil surrounding the ground rod moist. Concrete floors normally have iron reinforcement and connecting to that iron will improve grounding.

The size of the ground connection cable usually is not required to be larger than the power supply wire and is often smaller.

Read this

http://www.weschler.com/_upload/sitepdfs/techref/gettingdowntoearth.pdf

I have that printed as a reference in my "library". It's a good read.

Here is the user manual for the Megger DET14C and DET24C clamp on earth resistance meters

http://www.meggernetworks.com/LinkClick.aspx?fileticket=ABWpvwG8uQc%3D&tabid=1047

I've got a hunch that OP might be a little lost.

If you are still reading then please tell us what you are trying to achieve apart from a "substantial" ground connection. Describe your installation/application.

Clamp on earth testers? You live and learn. A had to check out how these fangled gadgets work. Unless there are other parallel ground connections then it won't it seems.

I spend a alot of effort when designing grounding systems to eliminate parallel (incidental) ground connections so I don't see how this can help.....unless you want to measure the resistance to ground of individual electrodes in a grid or some such....and then the others actually have to be good for the algorithm's assumption (ie R//=0) to stand fast and resolve a sensible result.

I think OP has a clamp meter with an ohm meter built in, not a new fangled clamp on earth resistance meter.

"I think OP has a clamp meter with an ohm meter built in, not a new fangled clamp on earth resistance meter."

I think you are right. My earth ground tester (and none others that I have seen) have clamps that can also be used with probes.

I don't really think they are new fangled, however. I've been using them since the 80's. For accurate ground readings they can't be beat.

What's the make and model for that one Pete? 4 wire or 3 wire? (or something else)

Currently I have a Fluke 1623.

I'd have to check my paper brain for what we used in years past.