Scary stuff, when you realize what the potential is! We were replacing a 200 amp main breaker the other day, [De-energized] and after removing the one mounting screw, the entire assembly just fell apart. If live, L1,L2 would have been shorting. After doing electrical 30 + yrs, makes you have more respect when you open that panel, exposing the main breaker.
My old boss was picking up the crew when one of the workers got in he stunk up the van. Turns out he did a rewire that morning on a 12/2 circuit that shorted with the wrong breaker and melted 30 feet of wire inside the drywall around the room. He bought the wire to show us on the way to work.
4:05. That last one with the #18 also illustrates why we have rules for feeder taps at ¹/¹⁰ the ampacity of the OCPD on the line side of the tap for the 10 foot tap rule, and ⅓ ampacity of the OCPD line side of tap for the 25 foot tap rule. Not to mention resistance goes up as the conductor heats up reducing the fault current and increasing the clearing time of the OCPD to the point of not providing adequate protection if a short circuit occurs on the tap and the rules are not followed.
Great vidio.Was extreme!y fortunate to have a company that purchased everything except for PPE rated under shirts. Had PPE rated hoodies, & winter rated PPE jackets. Our visors on hard hats had darker green tint.Should mention that rubber & canvas gloves must be sent out every 6 months to be tested & date stamped. Should wear 100% cotton socks ( which I could never find ) & electrical rated work boots good for 1,000 volts ( have no metal eyelets. Always had trouble with every GE garbage 13.2 KV switchgear. Worst was a POS GE 13.2KV dual service outdoor switchgear. It had an ARC flash rating of 120 CAL and moron engineers in training installed vents at eye !evel. ( which guarantees to not only burn your head but blow it off your body ) Was told that any arc fault above 50 cal no matter what approved PPE one would be wearing is guaranteed to kill due to blast would throw you back over 20' .Of course like all GE switchgear it had serious problems within a year with moisture building up and you smell the think produced by high voltage corona. Had to install strip heaters to keep humidity down. Think OSHA requires that you replace all hard hats who very two years but that seldom happens If you need a PPE Hood for high voltage spend the extra money for the style that has a built in cooling fan that runs in 6 AA batteries. Never use fabrics softer on any PPE rated pants shirts or jump suites when you wash the stinky things !
Q for Quinn makes 98% cotton socks but I prefer Darn Tough merino wool work socks because of the lifetime warranty. Also, a company called Woolley makes 100% merino wool underwear as well.
Well that's cool. I've seen a handful of videos where this accidentally happens I've never seen it on purpose. Just be glad you don't have one of those federal fire pacific breaker panels................. And you're not in the loft of a old restaurant. One of these days I'm going to find that video again.....
So if I'm understanding electricity properly: the delay in the breaker due to smaller gauge wire is most likely due to current limiting done by the wire. Is that right?
On the last one, what was the flash from the room with the panel? Was an arc flash visible there when the breaker tripped, even though it's a solid black casing?
i think the breaker exceeded the rating of the wire, and by chance, the resistance of the dead-short wasnt enough to pop the breaker, but was still enough to cause melting so the whole length of wire began melting, insulation fell off, and then it began shorting at other points, reducing the resistance and increasing current further, and arcing out of frame if it didnt short itself shorter, it could have been a demo of how a fire starts in walls
I think that was the breaker clearing the dead short. Inside the breaker are a series of plates arranged in a row, like a comb. This provides more surface area to dissipate the arc created inside the breaker when the breaker opens. Search for a video titled MCB, how do they work. It will show the mechanism better than I can describe.
Not sure what type of wire was used, but if it was thhn meant for in conduit then you'd be looking at 75c rating of 18A so appropriate breaker would be 15A; they had it on a 60A breaker which means the breaker will require a larger surge before it trips. The appropriate 15A breaker should have prevented the wire from melting.
@@jovetj I won't be so kind to the OP , it is an incredibly stupid thing to do for many reasons: Arc flash, arc damage to customer's walls/floors/etc, if the breaker doesn't trip you will have overheating wire or burning connections upstream, you can easily start a fire in a box with bad connections, and you will also scare the customer and look like a total asshat in front of them. All the companies I ever worked for had the policy that anyone who tries this stunt gets terminated immediately.
This was sort of a stupid exercise. More driven by ego and vanity. Not impressed at all by the silly over-confidence. Pretty dangerous example of things you should not do(intentionally) :(
@@jaybadass2318 Sparks of shorting little wires together is not an arc of electricity flowing through the air. An arc flash (specifically the light) is electricity flowing openly through the air. AKA just like lightning.