Importance of CAT ratings

[zog]

I have seen so many people say that they are safe and have so many years experience that they think they are qualified, well so did this guy. This artice covers the importance of CAT ratings and updating your companies safety training. The victim here was an experienced IBEW electrician that believed he was safe.



http://ecmweb.com/ops_maintenance/defective-test-equipment-20100101/

 

[cpal]

Good post this is the type of info that needs to get out!!

 

[LawnGuyLandSparky]

Great post, but there is still the question of what was happening in the mall before the electrician ever showed up?

 

[dbuckley]

Wow.

About thirty years ago I was measuring a 415V system with a non-Cat-Anything multimeter, on its 1000V range, and the multimeter went bang, though with nothing of the ferocity of this event; the meter was still physically intact. I returned it to the vendor, who asserted that I was changing the voltage range when the incident occured...

Clearly, luck was with me that day...

 

[cpal]

Wow.

About thirty years ago I was measuring a 415V system with a non-Cat-Anything multimeter, on its 1000V range, and the multimeter went bang, though with nothing of the ferocity of this event; the meter was still physically intact. I returned it to the vendor, who asserted that I was changing the voltage range when the incident occured...

Clearly, luck was with me that day...

luck indeed but to day with the newer energy codes distribution systems are more efficent and fault current is higher. depending on where you were in the system, the results today may have yielded a very different result.

 

[zog]

Good post this is the type of info that needs to get out!!

I have a safety FAQ in this section covering this issue, CAT ratings were always the biggest suprise to my students, most of which had been doign electrical work for 20-30 years.

http://forums.mikeholt.com/showthread.php?t=99114

 

[K8MHZ]

One of my friends is a care taker for several homes. One day he was checking voltage in a 120/240 panel and his meter blew up in his face.

When he told me about it I asked what kind of meter it was and if it had a CAT rating or not. He said it was a cheapo digital. He knew nothing of the rating. Of course, he got the usual 'don't screw with electrical stuff' lecture from me, which was probably no longer needed after this incedent.

Yes, meters DO EXPLODE!

I have also heard of decent meters exploding while checking voltages. One incedent invoved the meter being outside in the cold and getting condensation inside which provided a path for a fault.