Clamp-on versus split jaw ammeters

[kspifldorf]

In 110.7(F) of NFPA 70E, there's a reference to a risk evaluation procedure flow chart that states near the end of it: "Is the task only to measure current with a clamp-on ammeter?" Does this mean we can't use a split jaw? Is there a better way to define this? We currently use split jaw because of the speed, and they are less likeliness to tangle when you have to 40 panels a day, with 12 483 phase contacors in each. I understand that the flow chart is not a requirement and so on, but our safety man is getting carried away with this wording. Wouldn't 110.9 cover this?

 

[brian john]

Does this mean we can't use a split jaw?

Split Jaw? maybe different terminolgy, a picture or web link we can relate too?

Is there a better way to define this?

There must be because I am not sure what you are refering too?

with 12 483 phase contacors in each.

12 483 ?

 

[ironman3452]

in the nfpa 70-e2004edition, 110.9 relates to equipment use, but says nothing about clamp on meters, or split jaw ammeters, hope this helps

 

[kspifldorf]

I don't know how to attach Pic. Search Grainger "Ammeter".
483 phase......Remember?
110.7 refers you to the Annex F

 

[brian john]

483 phase......Remember?

I thought so!

to post an image you need to upload the image to a site Like Photobucket it helps to re-size the image on your PC or in Photobucket EDIT/RESIZE.

Copy line 4 and past here.

 

[kspifldorf]

Copy line 4 and past here.
huhh??

 

[76nemo]

Split jaw as in Fluke's T5-1000.

 

[jim dungar]

In 110.7(F) of NFPA 70E, there's a reference to a risk evaluation procedure flow chart that states near the end of it: "Is the task only to measure current with a clamp-on ammeter?" Does this mean we can't use a split jaw? Is there a better way to define this? We currently use split jaw because of the speed, and they are less likeliness to tangle when you have to 40 panels a day, with 12 483 phase contacors in each. I understand that the flow chart is not a requirement and so on, but our safety man is getting carried away with this wording. Wouldn't 110.9 cover this?

They are using the term split jaw to generically refer to a method of current measurement that does not require you to "break" the conductor, like an in-line meter would have to do.

 

[kspifldorf]

[/IMG]
Let me see
Tada!! Yea fer me..

 

[brian john]

I never gave those meters (posted) a thought, I am a meter snob I guess.

Now what was the question?

 

[electricalperson]

i prefer clamp on. i never really used split jaw meters before. only clamp on in my tool bag is the fluke 337. i need to get a flexible current transformer to use for larger conductors since i have a hard time sometimes using the 337 to wrap around conductors in panels and troughs. i could use it with my fluke 117 multimeter i suppose since it has a milivolt setting

edit: nevermind about the fluke flexible CT for the 117. millivolt range is only up to 600 millivolts. need to save up for the 289

 

[76nemo]

I never gave those meters (posted) a thought, I am a meter snob I guess.

Now what was the question?

My first question would be,....why do you not trust those testers if the conductor is aligned with the indication mark??? Just curious. I carry one as a frontline and second guess with a 337. What is your opinion??????

 

[76nemo]

My first question would be,....why do you not trust those testers if the conductor is aligned with the indication mark??? Just curious. I carry one as a frontline and second guess with a 337. What is your opinion??????

Now, I understand the T5-1000 is not RMS, but it can be a good way to start on finding harmonic issues

 

[brian john]

My first question would be,....why do you not trust those testers if the conductor is aligned with the indication mark??? Just curious. I carry one as a front line and second guess with a 337

I did not say I don't trust them, I said I don't use them. Check my tool case the last thing I need at this time is another amp meter. IMO doing the type of work I do it looks (TRYING TO BE POLITACALLY CORRECT) a little cheesy.

I said I am a meter snob.

These are only a small portion of the 30-40 CT's I utilize.

 

[kspifldorf]

I guess my point was that we tend to use the split jaw for the particular purpose of finding a lost phase., these heat contactors only stay on for a few seconds, its nice to catch all three legs in one cycle of the contactor instead of waiting on the next cycle about a minute later. When you've got like I said 40 panels and 16 contactors per panel that can be very time consuming. I'm not promoting being in a hurry or carelessness, especially doing live work. I feel these are safer because they do not get hung up. Again our safety guy is getting carried away with the wording of Clamp-on.

 

[gar]

080701-0745 EST

kspifldorf:

It seems your safety guy is asking the wrong question. If I understand your meaning of lost phase as no current or at least a very large difference in currents, then accuracy is not the issue, but current detection is.

To do this you could use a Hall effect probe close to the wire, a few thousand turn coil adjacent to a conductor with moderate AC current is a good detector also.

.

 

[nakulak]

I did not say I don't trust them, I said I don't use them. Check my tool case the last thing I need at this time is another amp meter. IMO doing the type of work I do it looks (TRYING TO BE POLITACALLY CORRECT) a little cheesy.

I said I am a meter snob.

These are only a small portion of the 30-40 CT's I utilize.

dang,

I expected Brian would have a wood stove, or at least a fireplace insert.

 

[brian john]

I bought a fireplace insert for Christams and my wife never arranged for the install.

 

[electricalperson]

I did not say I don't trust them, I said I don't use them. Check my tool case the last thing I need at this time is another amp meter. IMO doing the type of work I do it looks (TRYING TO BE POLITACALLY CORRECT) a little cheesy.

I said I am a meter snob.

These are only a small portion of the 30-40 CT's I utilize.

what kind of fluke meter is that?

 

[brian john]

AEMC
2620 Leakage Current Meters and Probes
The Model 2620 measures leakage current shunted to ground caused by insulation faults. It enables the operator to locate failures when they occur, or anticipate them before they occur, without shutting down equipment or spending hours troubleshooting.

It is designed specifically for locating low current faults on high current loads. The detector is a sensitive nickel alloy AC current transformer capable of measuring differential or leakage current as low as 500?A, and may be used to measure current up to 400A continuous duty.

The Model 2620 provides two output ranges: 1mV/mAac or 1mV/Aac. The output leads are terminated with standard 4mm banana plugs capable of interfacing with any standard multimeter. With its 4" jaw opening and range of 500?A to 200A, the Model 2620 provides a versatile way to analyze unbalanced current measurements, leakage values on grounding conductors and ground loop currents.