Closet electrical work path of least resistance

Yeah if you plug something into a 20 amp circuit, need to take into account whether that device itself is in fact rated for that amperage, OR has the appropriate fuse to protect it's wiring.

As for space heaters that CAN be an issue, when my furnace broke down I had like 6 space heaters around the house as I did not have my wood stove setup yet. At some point I did trip some breakers when trying to run them on high until I figured out which plugs were on their own circuit. I found if I run them all on low, it was still plenty of heat though so I did that, just to reduce the draw on any given circuit. If I were to build from scratch I would consider adding baseboard heaters everywhere as they are relatively cheap, very simple, and act as a good source of backup heat. Either that or just run at least 1 dedicated 20 amp outlet in each room/area.

Hmmm... Interesting pet peeve. 😊

I had never heard of duplex receptacles being split in order to be fed by different circuit breakers. Only seen receptacles split so that one socket can be controlled by a switch, but IIRCC both still fed from the same breaker. Would much rather have each breaker serve fewer receptacles than split receptacles between breakers.

My understanding is that the non-GFCI circuit breaker's trip value are meant to limit current to something less than the rated current carrying capacities of the house wiring (and switches and receptacles). House circuit breakers are not intended to provide protection for the devices plugged into the house wiring. It is up to the plugged-in devices to limit the current they draw. Neither a 15A or 20A breaker provides meaningful overcurrent protection for an LED light bulb. Seems to me that the breakers just protect against short circuits and wiring overloads. But I could be wrong...

Kitchen outlets are often split, called a multi wire branch circuit (MWBC). They go to a double pole breaker. The idea is because they use both legs, they can share a neutral as it's only the difference in current that passes through it and you can plug two high draw appliances in same outlet (one on top one on bottom).

For running random utility outlets I wouldn't bother doing it that way though, it would take up lot of space in the panel.

Power Eng, that is another way to use a Split Duplex receptacle fed from a single 15 A breaker. Obviously you are familiar with the small metal link that can be broken off a standard duplex receptacle to Split the fixture into two sockets electrically separate. I first learned about using them as I described in 1971 when I re-wired an old house we had just bought that had genuine Knob-and-Tube wiring from a 60 A 120 / 240 V supply. First time I'd ever seen that old style. I installed a 100 A panel and mast system, and all new wiring throughout the house. I had to learn all the relevant Ontario Electrical Code for residential uses to do the job and get it approved by Inspectors. Code then required at minimum three Split Duplex above the counter area plus one near the dining table of the Kitchen, but did not call for GFCI's. So that ensured 4 duplex (double pole) breakers or fuse blocks, and 8 sockets each rated for 120 VAC 15 A minimum in the kitchen. Additional circuits were required for major appliances like fridge or dishwasher. As Red Squirrel says above, they use 14/3 cable because the White Neutral line really is carrying only the DIFFERENCE in current between the two items plugged into the sockets. That design was a way to provide many 15 A circuits in a small space, and recognized that it would not be necessary to offer more than ONE socket for each 15 A circuit since the appliances EACH could draw a lot of amps!

As an aside, my most recent wiring job was a new garage we had built two years ago. I planned that job with the thought of future high-current EV chargers, so the feed to the garage is 120 / 240 VAC 100 A from the house panel. We also replaced our furnace at that time, adding AC. So for those electrical load plans we had the old 100 A panel and mast in the house upgraded to 200 A by a contractor who simply connected old cables into the new panel. The same contractor installed the buried cable (000 Aluminum) to the garage in a trench we dug. I installed the sub-panel and wiring in the garage. All of it inspected and approved properly. We also added in the same trench a pair of direct-burial CAT6 cables to extend our house wired Gigabit LAN (double cables for redundancy) there, and fitted a switch and WiFi Point of Access unit (suited to -40C) in the garage. That is used for a couple of smart switches on exterior lights, for the "smart" garage door opener and for Web access from my phone for car servicing apps. I am NOT an electrician. I'm a retired Industrial Chemist.

Interesting. Learn something every day. 👍🏻

FWIW I an not an electrician either. My experience is on the utility side with three phases and voltages measured in kV. I am not familiar with the intricacies of the electrical codes applied to commercial or residential buildings - especially in Canada. 🍁 I bow to your extensive hands-on experience. 🙇🏻‍♂️

That said, I will note that for the described 14/3 wiring to work the way described with the neutral only carrying the difference in current, the two breakers need to be taking 120 V power from opposite sides (and therefore reversed polarity) of the center tapped 240 v incoming service. If not then the currents will add together rather than subtract from each other on the neutral wire.

PowerEng you are right, of course. The standard way to do that is to mount in the breaker box a duplex breaker that is designed to draw its current for the two output poles from the two DIFFERENT Hot buss bars. (In fuse panels, a pair of fuses is mounted in a removable fuse block that does the same thing when inserted into its matching socket in the panel.) That way the current returned on the white Neutral wire in the cable is only the difference. But also, it means that if EITHER hot line is overloaded to trip the breaker, BOTH sides of the breaker are opened and ALL wires in the circuit become "dead". This ensures no dangerous power supply anywhere downstream from the breaker for safe work by service people. Likewise, without a breaker overload trip, simply manually shutting off the breaker removes power to both outputs.

A small caution, though, to service personnel that applies to ALL branch circuits in a domestic electrical system or the like. A breaker or fuse will remove all power to the (Black and / or Red) Hot lines in the circuit. However, the White NEUTRAL line is still connected to the panel's Neutral bus, and it is possible (rarely) that the Neutral Bus may have a Voltage significantly higher than Ground (the bare bonding wire in the cable).

Your experience is directly opposite from mine. I do NOT understand high-voltage power distribution systems, but I know the conditions and cautions are completely different from domestic wiring.

Paperdoc said:

PowerEng you are right, of course. The standard way to do that is to mount in the breaker box a duplex breaker that is designed to draw its current for the two output poles from the two DIFFERENT Hot buss bars. (In fuse panels, a pair of fuses is mounted in a removable fuse block that does the same thing when inserted into its matching socket in the panel.) That way the current returned on the white Neutral wire in the cable is only the difference. But also, it means that if EITHER hot line is overloaded to trip the breaker, BOTH sides of the breaker are opened and ALL wires in the circuit become "dead". This ensures no dangerous power supply anywhere downstream from the breaker for safe work by service people. Likewise, without a breaker overload trip, simply manually shutting off the breaker removes power to both outputs.

A small caution, though, to service personnel that applies to ALL branch circuits in a domestic electrical system or the like. A breaker or fuse will remove all power to the (Black and / or Red) Hot lines in the circuit. However, the White NEUTRAL line is still connected to the panel's Neutral bus, and it is possible (rarely) that the Neutral Bus may have a Voltage significantly higher than Ground (the bare bonding wire in the cable).

Your experience is directly opposite from mine. I do NOT understand high-voltage power distribution systems, but I know the conditions and cautions are completely different from domestic wiring.

Click to expand...

Actually they're pretty much the same, don't touch the sparky bit.

ah... yea.. I can tell you guys are not electricians.



code for a kitchen has been for a good long time a minimum 2 x 20amp branch circuits that feed counter top outlets. further it is inherently against modern code to do split phase outlets because there is no way to GFI protect them. A GFI measures the difference in current between the hot and N lines and will trip with less than 6 mA of difference. ( a GFI outlet or breaker does not need a ground to function, it is code to install all GFI outlets in a house with no grounds as a means of personal protection)

caveat: there are a couple breaker manufactures that recently started offering 2 pole GFI breakers that will work on a multiwire branch circuit.

It has never been the job of the breaker to protect a plugged in device.

You can put 15 amp outlets on a 20 amp branch circ because a 20 amp plug will not fit in a 15 amp outlet. the 20 amp circ is there to supply multiple 15 amp outlets. There is no code limit to the number of outlets you can put on one circuit in residential construction. The things you plug in should be limited to 15 by their manufacture if they have a 15 amp plug. The breaker is there to protect the wire, not the device you plug in.

Quit buying non-ul listed shit on amazon. I put it in all my quotes that i will only install things that are ul listed, or i will provide no warranty and reserve the right to charge more for modifying your shitty amazon thing.

CEC does have some slight differences to NEC but for the most part it is the same.

herm0016, you said, "It has never been the job of the breaker to protect a plugged in device". I always wondered about that! Seems to me that protection for the end device is important, but I never knew whether most Electrical Codes require anything like that. So I assume that such protection is within the CSA (Canada) and UL certification requirements, not in Electrical Codes. From a legal enforcement standpoint, putting that responsibility on the user device rather than on the building wiring system makes sense, I guess.

Yeah, I fully understand why designing a GFCI unit for a 2-pole breaker would be difficult (and hence maybe so costly nobody would buy). And certainly the REQUIREMENT to install only GFCI's in proximity to water sources makes use of older Split Duplex receptacle units banned in those positions. I presume you meant to say, "will trip with MORE THAN 5 mA of difference". And I'm glad you pointed out that a GFCI unit does NOT require a bonding (Ground) wire in the supply lines. So they are widely used for "upgrades" to provide some added protection in houses with no bonding wires already in their cables. The ARE an improvement for modest cost compared to re-wiring, but they do not provide Ground connections. I've made that point sometimes to users of electronic devices (TV, computer, etc.) that rely on a good real Ground via the power cord to connect cable shields for electrical noise reduction in signals. For that purpose, the presence of a third hole in a GFCI device can be misinterpreted.