Any comments on how well these work and what brands to get/stay away from? Seems like not having to install test rods or break the ground connection is a big plus.

Thanks for any comments!

I've heard nothing 'bad' about any of these tools, but I want to add I have not used any.

Call this post a 'warning shot' across every electricians' bow.

The NEC just says you need a ground rod ... that's ONE ground rod ... unless the resistance is greater than 25 ohms, in which case a second rod is needed.

The first aspect is that some have turned this requirement inside-out, saying that YOU have to 'prove' that your rod has the required low resistance - or, you MUST drive a second rod.

Next, every HI wants one of these gizmos so they can discover new 'defects.'

Together, these create a bias that we've been doing it all wrong for the past century, and that a single rod in never enough.

I think that is the perception. I usually hear the defacto answer is drive two rods if that is your only electrode. Florida pretty much makes the Ufer mandatory in new construction since the Ufer inspection is part of the footer inspection so it will always be "available". If you lose that connection you will be chipping concrete in most jurisdictions. That is why the "7 iron" is so popular. There is no exposed copper to be broken off and/or stolen.

We don't see many rods any more in my area but the rules here are 2 - 10 foot rods 3 meters apart. There is so much rock and hardpan clay that ground plates are the rule except for a counterpoise ground for a HV service.
We dropped the resistance requirement from our code a long time ago.
Given the role a Ground wire serves I think it is mostly all overkill. It is rare that high voltages including lightning ever get on the low voltage wires, the neutral is the real fault current path to the source anyway.

The function of the ground is not to clear faults, it is to create a local ground reference so the case of your drill is at the same potential as the concrete slab you are sitting on. In that regard, the ufer is your best bet. Earth ends up being a significant return path for neutral current tho, in spite of the theory and 250.6. Wye distribution pretty much assures it. Even with delta distribution, you will still be sharing the earth with the neutral. You want a local ground reference.

I'm not sure what you mean by "the 7 iron," Greg. A picture. perhaps?

That term came from here. It is when you turn up a piece of rebar, built into the wall and make the Ufer connection there.
That is very popular here in SW Florida but right across the swamp on the East Coast, AHJs don't like it.

http://gfretwell.com/electrical/ufer.jpg

Reno:

As to the '2 rods'...basically most ECs I know 'just do it', as if it's looked at in a dollars and sense standpoint. Taking into account the $$$ of testing equipment, driving the reference rods & performing the test, economical sense is to drive the second rod & the job is done.

For some time, quite a few guys still installed rods with Ufers, and I still find the occasional 'water ground' with a jumper on the 2" plastic main, and PEX piped resi.

I can't say I've ever used one of these clamp-on type testers.
I've always used the one with the two test rods, I suppose it's what you're bought up with I guess.

Mike:

Could you say about how much time you need to do a earth resistance test with the tool you mention above.

Could you put a dollar value on the cost to perform the test? US$ or NZ Dollars, & I'll use the exchange rates here.

Is it a standard practice for you to do the test, or just for 'special occasions'?

Stay safe!

Despite the various ads, in my memory these testers were not originally developed for testing ground rods!

I recall various testing firms using them, instead, for the testing of equipment bonds .... that is, to verify that the 2" pipe really could clear a fault if the 150-amp conductors within had a major fault.

Testing grounds isn't a bad thing; better to KNOW than to just 'think.' I do question the use of various devices by untrained "Inspector Gadgets." I also question the wisdom of trying to legislate perfection.

Sorry if I got the thread off on a tangent. IMO, were I to buy one of these testers, I'd be just as happy with the lesser-known names; Fluke didn't invent them, nor do I see any advantage in their pricier version.

Hi John,
Umm, it doesn't actually take that long to do one of these tests, I'm talking in under 10 minutes.
I modified the test stakes and welded some steel plates to the tops of them to make driving them easier and a tool to pull them out of the ground again.

Pretty much, most of the time involved with this test is the set-up and take-down afterwards.
The meter I use, a Metrohm, gives you an instant readout in Ohms, so there are no awkward calcs to do.


Regarding the need to do these tests, it really depends upon who you ask.
Under our current Regulations, you are required to test the "effectiveness of the Earth Electrode, before the installation is connected to a source of supply".
Coming from a Line Mechanic back-ground, this is a test I'd never fail to do

They don't peel back the outer layer of Pex-Al-Pex pipe to bond to the Al layer? Those lazy clowns!

Larry C

Attempting to 'ground' plastic pipe onto the aluminum mid-layer? Jeez, someones going to try it for sure! Peeling back the outer layer of PEX would compromise the anti-oxygen penetration properties of the pipe and seriously weaken its pressure capability. Nicking the inner layer would be almost a certainty. Result: Call back with a mop!

Everyone knows you bond plastic pipe with weed eater string and use a tywrap for the clamp.

It's going to be tough selling such meters out my way.

My AHJ insists upon Ufers with #4 bonding all around on the GEC System and 200A minimums.

For temp power, only, we can get away with a ground rod -- just one -- and the temp Service is limited to 100A.