How good is ETL safety certification?

Fuses to the IEC specs have a rupture current rating.

L = low breaking capacity. H= high breaking capacity.

E.g T300mAL meaning T = time delay ( 'slo blo' )300mA - Low breaking capacity.

Graham

A lot of those measures are about arc extinguishing.

Must be tricky @ 15kV though !

Graham

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I think it'd be fun to blow one and watch! To see if it actually melts the sand, and how that ceramic form would stand up, and stuff like that.

Unfortunately, this is the sport of the kind of kings who have a

Cheers! Rich

when the little cylinder is full of metal vapor it takes less than 500 volts to maintain the arc for a few seconds especially if that voltage is DC.

Bye. Jasen

I have been gaining this impression that dollar stores get a lot of stuff that is fake in one way or another. I have had a dollar store compact fluorescent lamps burn out in an uncomfortably spectacular manner a few minutes after I started running it. Also I have heard of others having spectacular failures of dollar store compact fluorescent lamps, including one that went "pop" 3 times in the process of burning out.

And also fakes in matters other than safety - how about those flashlights that say they never need batteries - shake to recharge? In my expereince, the $2 dollar-store version (in 2 different packages now yet!) has a fake magnet, a shorted coil, and non-rechargeable "coin style" batteries.

Maybe I will send the FTC a dollar store compact fluorescent lamp that produces somewhere around 30% of its claimed light output, in its package that claims 1580 lumens and "light of a 100 watt bulb". I have yet to see a dollar store compact fluorescent lamp meet a light output claim. Some dollar store compact fluorescent lamps also claim "soft warm white light" but actually glow a bluish "daylight" color.

- Don Klipstein ( snipped-for-privacy@misty.com)

Vaporized metal can sustain an arc that long (I am assuming length of an AGC style fuse) with even less voltage than that. Try seeing how long an arc you can draw with an arc welder at merely 30-40 volts or so, and then imagine what 500 or even 250 volts can do. I once had an arc almost an inch long between 12 AWG copper wires with only 2-3 amps at 120 volts during an experiment trying to see the spectrum of a copper vapor arc.

Also, fuses often have a lower voltage rating for DC than for AC.

- Don Klipstein ( snipped-for-privacy@misty.com)

May work OK with AC voltage that high, especially if it is a lower current fuse - but it has not been tested and certified to be reliably safe/effective in such use. May even usually work OK. May work OK when you try it, and then your luck may run out sometime later if that fuse is somewhere other than under your eyes or sometime when you (or worse still others) don't know where the power disconnect and the fire extinguisher are.

- Don Klipstein ( snipped-for-privacy@misty.com)

Hello Don,

I don't buy at Dollar stores but I did buy a six-pack of CFL for under $6 at Home Depot. So that's under a dollar a pop. They work great, unlike many of the more expensive ones I had. The light is spectrally more filament-like and they start instantly, just like a bulb.

Merry Christmas, Joerg

Hello Don,

It is also a matter of energy to be absorbed. A 1A fuse blowing in a 24V circuit because the current gradually sauntered towards 2A is one thing, the same fuse in a 240V mains circuit experiencing a sudden dead short on the other side is quite another. The breaker for such circuits can be designed for 16A or more depending on where you are in Europe.

I've had fuses spewing their glass and sand all over the place and leaving nasty scorch marks. I don't think running fuses above their maximum voltage rating is a good idea. If a manufacturer does it anyway and something happens the lawyers will be all over them.

Regards, Joerg