Hello,

I'm looking to buy a decent clamp meter. In case I'm using the wrong term, here's a picture of what I'm referring to:
http://www.globalspec.com/NpaPics/31/90923_031020041314_ExhibitPic.jpg

The thing is, I'm kind of confused by all the choices out there. I'm looking to spend a maximum of $100 (but I may be willing to go a bit higher if it's worth it). Lowe's sells the ones made by Greenlee, which I hear are pretty good. My friend has one that cost him around $230 - clearly not the one I am looking for. I saw one in Lowe's for around $60. I wonder if that's good... Also, quite a few people have told me that I shouldn't bother with Greenlee, but rather get one made by Fluke, which are better. I've also heard that I should look for a feature called "True RMS". I've also been told that there's four catergories of devices, depending on how strong of a current they can measure.

So you can understand why I'm confused - I'm a bit overwhelmed by this whole "information overload". So maybe someone can help me out. I'm looking for a clamp meter to measure standard house wiring (i.e. I may measure 12 and 14 AWG wires, and occasionally even the big fat wires that feed the main panel, but I'm not trying to measure 4/0 utility lines or any thing - just basic stuff). Will a cheap one suffice (perhaps Cat II or III)? Also what the heck is "True RMS"? And what is to be gained out of getting a more expensive unit - are they more accurate, or do they just have a higher measuring capacity? If the cheaper ones are less accurate, what's the "margin of error" - a couple of watts, or can they even be, say, an entire amp off the mark?

Any advice would be much appreciated!

Thank you,
Moishe

Take my word for it, any meter you buy should be rated "True RMS" .

Explaining True RMS is very deep subject, way beyond the scope of this forum, and the time I have to type. Bascially it reads the average of the values of current, since AC voltage and current are ever changing 120 times per second.

Here is a web page that explains it as simple as I can find:

http://www.kpsec.freeuk.com/acdc.htm

For your purpose, buy the best you can afford, or as often as you will use it, the least expensive. Sure the more money the better the accuracy, along with other bells and whistles you may or may not need.

I cannot really say much about the cheaper ones, as we use much more expensive units because we use them often and need accuracy. I have one Fluke that cost $400.00. Having a power quality recorder at $15K , and infrared camera at $60K, and sevearl other testing units each averaging $5K each, $400 is a drop in the bucket for an amprobe.

The cost is relative to the max amps the unit can measure. And sure, brand name often means more money, as usual.

Thanks very much TK. Don't worry - I read that page, and I understood perfectly wh

GAAAAAH!!! My stupid ISP went down while I was posting my response last night, so as a result, only one line of my message got through; the rest got cut off.

Here's what I wanted to say:

Thanks very much TK. Don't worry - I read that page, and I understood perfectly what RMS is (especially since I already knew about the sine-wave part from reading up on three-phase power). Thank you very much for taking the time to find that link for me - it really helped.


And sure, brand name often means more money, as usual.
Hmmmm... Greenlee and Fluke are both very good brand names, right? Which one do you think is better?

And by the way, what's that 65K IR camera, and what does it do? I'm curious - it must be something major for it to be worth 65 grand (that's more than many people make in a whole year ;))...

Thanks again,
Moishe

Both Greenlee and Fluke are good names.

However, Fluke only makes test equipment.

Greenlee makes drills, saws, wire pullers, hacksaw blades, knockout sets, limited amount of test equipment, etc. They must outsource and market some other make of test equipment. Never really looked to see if I can determine who's unit they may be marketing.

Get my drift?

The infrared camera is made by FLIR, the same company that makes the IR units found on helicopters for law enforcement, also used by fire depts to find humans in smoke filled buildings, and , of course the military.

They have this unit for preventive maintenance firms, we use it to scan live electrical equipment under normal load conditions for the purpose of finding loose connections, defective circuit breakers, etc, since these conditions create high heat at the failure points. If we can scan and find these hot spots before damage is done, the issues can be corrected, thus, saving expensive electrical switchgear from the damage the heat can cause, and keep the facility in business.

Like TKRussell said buy what you can afford. For the application you are dealing with a $100 meter should be fine. Unless you decide to bring in heavy duty motor loads and a radar site, or airplane testing equipment at 400hz in your house you don't need an expensive one. I may be mistaken TKrussell but I thought Fluke bought out Flir's biggest competitor

Ever get zapped by 400Hz?

Man what a feeling.

Makes your fillings vibrate.

Fluke bought Reliable power Meters a few years ago, and

Flir bought out Agema, a European Inrared camera maker.

Fluke... The Rolls-Royce of electrical measurement!
Go for it.
No Need To Say Any More.