Why Circuit Breakers DON'T Protect People (electric shocks)

:_Hazard: This free video took weeks to make! if it helped you and you'd like to thank or support Paul's efforts, link below: PayPal: www.paypal.me/TheEngineerinMindset Patreon: www.patreon.com/theengineeringmindset Channel membership: youtube.com/channel/UCk0fGHsCEzGig-rSzkfCjMw/join

The fact that you replied to my comment from 3 years ago and gave a link to this video was a nice gesture. I appreciate it

This is a gold standard for showing how breakers work. Very pleased with that

As an electrical engineer I have repeatedly attempted to explain circuit breaker operation and curves to technicians and electricians. No matter how extensive (or simplistic) I make my explanation it ends up with them offering up a sceptical look and them just accepting the answer without really gaining an understanding. This is an excellent video; I shall share this as the teaching video for breakers. Thanks so much for putting the effort in to creating it.

I'm loving this more live-action kind of videos

This is about the best video explaining how a MCB works. Well done.

@13:00 good to add that the arc chamber is "up" aka away from gravity. The arc travels up as heat rises due to gravity. If you install breakers upside down you can actually get good arcs to melt internals instead. It's a fun exercise lol awesome video as always

I'm glad you said qualified and competent at 4:20, because I've seen a lot of people who are competent who think they're qualified, and people who are qualified but aren't quite competent 😂

They’re not meant to protect people, they’re meant to protect circuits. That’s why they’re called “circuit breakers” and not “people protectors”.

Dude, the transitions are so freaking mind boggling! Great Job Paul!

Those circuit-breaker graphs are great! I learned a lot from this.

The title is a bit misleading. True, MCBs do not protect people from fatal electric shocks. However, they do protect people from electrical fires due to overloads and, statistically speaking, electrical fires have been a much killer of people than electric shocks (particularly in the USA I should add, partly because of the way they build houses). To say that it is just there to protect property is simply not the case. Also, some MCBs are twin pole, although that's more an industrial and European domestic thing (at least in some countries). However, excellent job at explaining how MCBs work, and especially the dual-mode switching and why it's done that way. I note, there is still no mention of RCBOs. Those dual RCD consumer units are, thankfully, rapidly being confined to history and many electricians will no longer quote for split RCD CUs, and I'm a bit surprised that the regulations still allow them. Of course, then we come onto a far more contentious point, which as AFDDs.

101 reason why you need a GFCI

MCB’s can be safely mixed because they are designed to a common mechanical and electrical standard. Different manufacturers only becomes an issue if a distribution comb is used but that can even be an issue even with in a specific brand. The leading letter refers to the trip curve which goes beyond B, C and D - “A” being fastest and “F” being slowest (and usually used for variable speed motor circuits (and occasionally switch mode power supplies with high inrush currents). C curve breakers are the most common in domestic use. Direct On Line started motors typically draw seven times the running current during start. Hard Start Switch Mode Power Supplies draw their full output load current during starting - so a 5V 1000A supply will draw 1000A for the first fraction of a cycle until the output reaches 5V - so from a 240V supply 240kW (and having tripped a gas fired power station offline by turning on a computer system, this could happen (steady state the system drew 1kW - the power supplies were oversized and redundant (2off)).

This was easily the best video I've ever seen on this topic in my whole life. Top tier quality right here

A clear, concise explanation of these magical devices. Awesome, & many thanks for your work. 👍

The clearest and simplest demonstration and explanation of how this works. Excellent work!

I'm an electrician and pretty much knew this stuff already. But you explained it so incredibly well and entertaining that I just had to watch the whole thing. Thank you!

Utterly brilliant description - thanks so much for taking the time to put this together!

Phenomenal video. I thought I understood breakers, but I never once looked at the trip charts nor had I noticed the Arc chamber. Thank you for this!