Are one of these fuses blown?

[Matt Meiser]

I had to take arc-flash training at my last job. They talked about numerous examples of meters exploding. There was one example where a meter case opened part way up and then closed back up with a bunch of the guys skin inside. If I recall correctly they recommended a meter marked at least Class III or maybe Class IV. They little electro-mechanical voltage testers (nicknamed "wiggy meters" around here) were outright banned in auto plants.

[Rod Sheridan]

Good point Matt, we also have to use a Cat IV 600V or Cat III 1000V meter.

Arc flash injuries aren't any fun..........Rod.

[Ken Fitzgerald]

I have to be recertified in arc flash annually and carry an arc flash kit. My rubber gloves can't be more than 1 year old....vest......helmet with shield.......leather gloves......

[Tom Esh]

I had to take arc-flash training at my last job. They talked about numerous examples of meters exploding....

Bingo Matt. That's why I won't get anywhere near mains or a panel with a cheap meter. Most injuries with MMs are not due to electrical shock, but rather burns and shrapnel. The case on a good one is essentially designed to contain a small explosion. Hard as it may be to get a Fluke to do anything but beep or blow a fuse, there's no stopping someone really determined to do something foolish.

[Sean lennon]

+1 on the use of fuses.

nothing better or more reliable.

I have seen many breakers that drift out spec after they have been tripped.

[Jarrett Vibert]

I have to be recertified in arc flash annually and carry an arc flash kit. My rubber gloves can't be more than 1 year old....vest......helmet with shield.......leather gloves......

My plant is just starting to get into compliance with arc flash regs on the floor. We've always had the suit, helmet/shield for the switch gear room though. Each electrician is issued 2 pairs of gloves. One is always out for testing, and gets swapped with the set in use when it returns.

Arc flash is serious business... Fortunately the management here force all personal to go through awareness training/scare session. It's only for those handful of weeks afterward that the operators tell me I'm worth what the company pays me.

[Ken Fitzgerald]

Jarrett,

You only have to see the photos of burned flesh once to be a believer. It's serious stuff.....or consider blindness....

[Jarrett Vibert]

or consider blindness....

I've been there, on temp basis mind you. Scariest 2 mins of my life... My worst at work accident by a long shot was by flash. I'd rather take a lift any day.

[Ken Fitzgerald]

Jarrett,

I became deaf in July of this year. I will be retiring shortly because of the safety and communications problems it causes. I can't talk on the phone, hear television or most peoples voices. It wasn't due to anything I did but it does make one consider safety with a different attitude.

[Jason Roehl]

Maybe I am mis-reading this, but, I thought when ohm'ing things if the needle moves you have continuity and hence a circuit. If the needle stays at zero, then no circuit, meaning a blown fuse. But maybe it is the type of fuse??

Thanks

If you have your multimeter set on resistance (Ohms), and it reads zero or very close to it, then that indicates continuity--a circuit, and the fuses would be good. A digital multimeter will show a tenth of an Ohm or so on a good fuse, and show OL (not sure--overload, out of limit or open loop) on a blown fuse.

[Phil Thien]

Could you guys versed in arc flash give those of us that aren't a little primer? At what kind of voltages/currents does this become a big concern?

[Jarrett Vibert]

To be honest, I had to google it to find real numbers. From what the great wiki tells me, systems operating below 208v phase to phase don't have enough potential to cause an arc flash. It more so the commerical/industrial systems 480v and up that it becomes a viable hazard.

Caution on the google image search if you have a weak stomach...

Not 100% on how we got into the discussion of arc flash here seeing as it really doesn't relate to the topic. However my mulitmeter warning stands...

[ray hampton]

On the multimeter that I use the needle are at rest on the left side of the meter face, a zero reading in OHMS would move the needle to the right-side of the meter face

[ray hampton]

I got a important Question for someone that have some experience with TIG welding and other HIGH Frequencies, PM me

[Jason Roehl]

I once saw a minor arc flash incident in a warehouse I was painting. One of the owners (a former electrician) was running a metal fish tape in some new, horizontal conduit on the ceiling to an open, empty junction box. Somehow, the tape, instead of coming out the open junction box, turned the corner down and went into a 3-phase panel, shorting at least one of the phases. All I saw were sparks (really, molten pieces of the fish tape) thrown out about 20+ feet. I was at least 50 feet away, and not looking directly at it, so well out of harm's way, but the noise and sparks sure got my attention! The owner was fine, too.