True, but in that sense, it may never become an issue. However, these receptacles are usually used for built-in appliances, in which case, you can often apply a load to the entire circuit.
You should be using your camera to “study” the electrical system of every inspection, even if you are not yet incorporating it into your report. This goes for any system that you will eventually include in your services. Take the opportunity to learn how to identify anomalies even before you are ready to report defects discovered through TI.
Do you I/R guys leave the oven, burners, dishwasher, clothes dryer etc on while doing the main panel? I hate leaving things on while unattended and am afraid of forgetting to turn them off while occupied elesewhere!
From the OP there isn’t much information besides the photo. Chuck has filled in some of the blanks along the way. Questions like these get us thinking of many different scenarios. Here’s another:
If this is under a code cycle prior to 2011 NEC the black and red conductors could share a #10 neutral and be code compliant. Obviously this wouldn’t apply to a normal cable but it could apply to a raceway.
Vacant or not, I will run all built-in appliances. I generally don’t operate portable appliances such as clothes-washers and clothes-dryers, but on some occasions I will. I also turn on all lights and fans.
Here are two double 20 amp breakers one is Both on the same phase .
The other has one one each leg One red one black .
uote: Originally Posted by rcookehttp://nachi.cachefly.net/forum/images/2006/buttons/viewpost.gif I think this is what some call a half breaker and they are fed from a single phase .so two on phase B overloads the neutral
But who is to say that those red and black comductors share the same neutral? This can not be determined from the photo. Many panels are so full that it is not possible to trace the conductors even back to the sheathing. Even if you could, that does not guarantee that the red and black are being used in a MWBC configuration at the other end.
Just getting in from today’s inspection and catching up on this.
First off, congrats to Juan and Chad for figuring it out with very little in the way of hints. I think It’s harder to do analysis from pictures than in-person.
Second, regarding the comments about how are you supposed to know it’s a MWBC from the picture: I can’t think of any valid configuration that would have two conductors sharing a neutral on a single pole breaker. It should be obvious that it couldn’t be a 240v circuit, because it wouldn’t work. Perhaps Robert Meier or one of the electrical Gurus can, but I can’t. I did try to provide what I though would be useful and relevant without a bunch of other distracting items in the photo. I was trying to make the discussion about this specific issue. It gave me an “ah ha” moment the first time I encountered one of these, so I thought it would be worth sharing. Thanks for the feedback.
Regarding infrared: This inspection did not include infrared so I did not have an IR image of the neutral and the panel was too crowded to get a clamp meter on it. I have a different approach to IR and home inspections than many HIs. I consider myself a professional thermographer, I offer the service to clients for a fee and they can elect it or decline it at their choice (the one exception is houses with aluminum wiring). I have about $50K invested in IR imagers, IR related equipment and training. When I use it during a home inspection I get paid for it.
Whenever I shoot a residential panel, I will load up the electrical system with whatever is available to me in the house. That usually includes all lights, fans, A/C systems, Ovens on high or self clean, dishwasher on sanitize, electric water heater making hot water, electric dryer running, etc. before I shoot the panel. I also have a clamp meter so that I can measure actual load. Don’t assume that it’s not worth doing electrical IR inspection on a new, unoccupied home. I have dozens of thermal exceptions from empty house electrical systems.
The issue with the MWBC is that the OP had a photo and not much information, by design of course. Most guessed that it was indeed a MWBC which shed some light on a few violations, but the photo and initial description didn’t provide enough detail to say conclusively that it was a MWBC.
Again, great post, we all like these kinds of challenges. The one scenario that comes to mind is if this wiring is in raceways with separate neutrals instead of being romex. Without seeing the neutral/s, this being a MWBC is still an assumption, though a probable one.
Ok so they are quad breakers. The only thing I see wrong is the top one does not have a label anymore so there is no way to know if the conductors are sized correctly
The colors of the handles are consistent - 15A = blue, 20A = red. I would have checked (if possible) to see what the outside poles of the bottom quad are connected to - may be a handle tie missing.
Well I didn’t realize it was color coded so don’t feel bad. I also spent the last hour looking up quad breakers and staring at that pic trying to figure out what marcel wanted us to see.
