Branch Circuit, Multiwire, NEC 2020 - [210.4], (19min:38sec)

I was working at a hospital, a maintenance electrician was working nearby. He opened a junction box and unbundled the neutrals while the circuit was energized. There was a nice POP ....... A few minutes later the Director of the Laboratory walked out into the hallway and asked why the power to a section of his lab just went out. At the end of the day, there was $120,000 worth of damaged equipment...It was a multi-wire branch circuit.

Thank you Mike for all the technical support, information-Advice that you share! 👏

I have wired a dozen or so homes ages ago for my father a gc. I messed up several jobs by overloading the neutral with breaker/leg misplacement. It was eventually caught, no damage done and corrected. Neutrals are anything but neutral, it should be called something else, like return, neutral minimizes the danger, much like interchangeably using grounding and bonding; that too is a deadly mistake. Just ask the families of the dead burned alive in the enclosed metallic bus stops with metallic grated benches... On a three phase panel, the 220 leg is orange and labeled stinger; a novice should head the messages; dont F with this. I digress; too many improperly trained, improper supervised and lazy inspectors create deadly hazards; like I did. Appreciate you!

Thank you for the great instruction and positive outlook on health and life! They are equally important in my opinion!

This guy is awesome, I would have paid much more attention if all my teachers were these good.

The Murphy's law thing made me lol, thanks for that.

Last year I opened a ceiling gang box to tap in for a doorbell transformer. When I removed the wire nut from the neutral, the home run white lifted. In a nearby study, a 6-outlet adapter with surge protection started sparking and smoking. I could not pull it out of the outlet as it was screwed in. I reconnected the neutral and was then able to remove the adapter and drop it outside while it continued to melt. The shared neutral condition had presented the surge protect circuit with over 120v.

Mike Holt gets me excited about electricity. Man I just love his vibe. Have a good day!

I can vouch for the Murphy's law of multi-wire circuits. Had a variant of such a circuit in a 240/120V all electric motorhome. Some 120V receptacles had 3 volts, others had 208 volts. Finally found an open neutral in the opposite end of the 40 foot vehicle (it was a loosened critical neutral crimp connector!), but too late to save the $2000+ RV fridge. :-(

Ran into this today. Two separate breakers, one neutral.

Great video. Very helpful. One thing that may cause people to connect multi wire branch circuits wrong is the use of tandem breakers. If you connect the two hots to two tandem breakers you will over load the neutral because tandem breakers are same leg. But many people assume that any adjacent breakers are always opposite leg. Tandem is an exception to that. Also I was surprised that no one mentioned that shared neutral is not compatible with gfci. That’s a good reason not to do it.

👍🏼 Thank you Mike and Company !! As a firefighter/paramedic who relies on your videos for extra knowledge, I must say you are a real lifesaver.

I’m sure the guy with his manager buddy appreciates the shout out for their insurance fraud at the Best Buy lightning incident!

What a great video. It explains in detail what every electrician should know about Multiwire circuits.

3 mins in and my head hurts. Salute to you guys

This helped thank you Mr.Holt!!!

watched the whole show... excellent

My house (built in 1978) has two MW circuits. Neither of them had handle ties for the breakers (they weren't even next to each other although they were on separate legs) AND the circuit to the laundry room used the device yoke for dividing it up!!. Needless to say, I fixed that very quickly. Neutral integrity is an absolute with MW circuits. Period. Reckon I'm showing my age here, but I also refer to these as "Edison" circuits.

The legend himself with another amazing video

Learned to tie the groups together when traversing a box. Thanks.