Multiwire branch circiuts

[iwire]

I really do not care if people 'butcher' my MWBCs after I leave anymore then I care when they butcher the rest of the installation.

Not my problem and if it was my problem I could not stop it from happening. You can not protect idiots from themselves.

 

[roger]

I just do not see any thing but up front cost savings with MWBC..after the upfront cost savings it is all down hill from there..

You sure that's all you see? What about savings on fuel to produce electricity, natural resources, wasted power in the way of wattage used, and others?

Think of the big picture

Roger

 

[dnem]

I have seen so many butchered MWBC that I will not design with them unless specifically requested to do so..

Some of these janitor-wanna-be-electricians move breakers around in the panel like they're playing a shell game. . They get doubled currents on their neutrals and then they wonder why the white insulation is turning brown and getting dry and flaky.

..so janitors can change ballast in box stores..these are the same people that screw up MWBC and are normally the ones getting hurt..We are not going to change the mentality of businesses that are cutting costs by having the under qualified doing electrical work..MWBC are dangerous to their health..

If there was as much supervision of work after the occupancy certificate is issued control over as there is for work done before the certificate is issued there wouldn't be this push to "dumb down" electrical work so that the unqualified don't get killed while butchering the job after the real electrician leaves. . How many of these businesses get permits/inspections for after occupancy changes to the original design ?

 

[dnem]

I really do not care if people 'butcher' my MWBCs after I leave anymore then I care when they butcher the rest of the installation.

Not my problem and if it was my problem I could not stop it from happening. You can not protect idiots from themselves.

The CMP guys believe [rightly or wrongly] that it's their problem that they need to solve and they believe that, altho they can't stop the butchering, they can lessen the total number of occurrences.
The CMPs believe they can protect idiots from themselves.

 

[frenchelectrican]

Some of these janitor-wanna-be-electricians move breakers around in the panel like they're playing a shell game. . They get doubled currents on their neutrals and then they wonder why the white insulation is turning brown and getting dry and flaky.

Yeah.,, Unforetally it getting routeine to see this all the time with MWBC set up and the wanna-be's don't really care about the safety all they want to just get it running but don't think about the safety.

Which that part it kinda ticked me off somehow.,,[ ]

If there was as much supervision of work after the occupancy certificate is issued control over as there is for work done before the certificate is issued there wouldn't be this push to "dumb down" electrical work so that the unqualified don't get killed while butchering the job after the real electrician leaves. . How many of these businesses get permits/inspections for after occupancy changes to the original design ?

that part i do agree with it and with the last sentence related to get the permits/inspection as far i can see more than half don't bother with it. Some of them told me they claim the permit cost more than just add a lousy circuit.,, .


Merci,Marc

 

[steveng]

I know better then this..because the MWBC is some what of a money safer in the up front costs of the install..I do believe though as time goes by and electrical costs increase maintenance personal do more and more work on electrical..My wife works for the government and their budgets are tight..there maintenance men also do the janitor work..they even run electrical wiring..

I am telling you it is wild..they move cubicles around and the maintenance people do it all..So they were having some computer problems and they had a contract with this computer company and the companies solution was to have the employees to spray the carpet with water to control the static..I finally told them to fix the grounding problem they had with the improperly run AC cable they were using..I explained it to them (maintenance supervisor) and the maintenance guys went and fixed it..they fired the computer company they used for servicing their computers..

Now I am telling you guys that no matter how many laws you pass and how many rules you have the under qualified are going to do electrical work..the rules are all about the safety of the under qualified and the non qualified..I really do believe that the MWBC are going to become a thing of the past..

I do understand the feeling about unqualified and under qualified but the regulations are to protect the unqualified..it is all about the safty..I have talked to the inspector about the issue but you know the drill and as long as they do the contractors on new installs..

I am not promoting the unqualified just know it exsistes and it is not going away..No delusions here..

cschmid, you are correct in that assumption, i see it more every day, in fact i am doing more every day, and we stop at the new installs, we let the contractors handle any new service installs and any other work that we are not qualified for, we do primarily lighting and receptacle
loads, and some room modifications, but they ask for more everyday.

we need the proper training and the know how, to appply the new codes, however, mgmt looks for cheaper ways to do the work, i look for qualified, conscientious contractors to help me do my job.

 

[tom baker]

, so a neutral for every conductor might be a more tolerable (if not more expensive) solution.

We call it a neutral but this wouldn't be! I agree we may be seeing the end of MWBCs. There is the danger of the open (oh-oh) neutral, couple of code rules to prevent - only one per terminal and pigtail. But the other rules, common trip, etc, are safety related, do you think they are due to electricians not checking voltage? Or unqualified persons?

 

[dnem]

I don't think we'll ever see MWBC completely disappear. . But there's no question that our new economy is driven and focused on the service sector. . It would be considered cutting edge if you could get unqualified people to deliver a pizza and then stick around long enough to change out a few ballasts and maybe get their hands into a panel and jumble up some of the breakers.

It's possible that 210.4 might eventually have wording like we see in 240.21(C)(3), "For industrial installations only ..... (1) Conditions of maintenance and supervision ensure that only qualified persons service the systems."

 

[cschmid]

I really do not care if people 'butcher' my MWBCs after I leave anymore then I care when they butcher the rest of the installation.

Not my problem and if it was my problem I could not stop it from happening. You can not protect idiots from themselves.

I agree with that..yet we have been trying to idiot proof the industry for years..

I do care about the people who are going to follow after my designs / installs..If I can make it simpler and safer at an affordable cost I will..

 

[cschmid]

You sure that's all you see? What about savings on fuel to produce electricity, natural resources, wasted power in the way of wattage used, and others?

Think of the big picture

Roger

Roger I do think about the big picture and I would bet bigger operations throw away more copper, than I use by not using multi wire circuits..There is no wasted power in running separate neutrals..

I don't see me as being a contributor to the environmental damage caused by corporate America raping the earth..I see it just the opposite if corporate America wanted me to be environmentally friendly they would make going green affordable..This is a whole new issue..Like some of the process for using sustainable resources are more toxic then the regular process..yet this is an issue for a different topic..

 

[cschmid]

Some of these janitor-wanna-be-electricians move breakers around in the panel like they're playing a shell game. . They get doubled currents on their neutrals and then they wonder why the white insulation is turning brown and getting dry and flaky.



If there was as much supervision of work after the occupancy certificate is issued control over as there is for work done before the certificate is issued there wouldn't be this push to "dumb down" electrical work so that the unqualified don't get killed while butchering the job after the real electrician leaves. . How many of these businesses get permits/inspections for after occupancy changes to the original design ?

Nicely phrased

 

[roger]

There is no wasted power in running separate neutrals..

Uhhhh?

Roger

 

[cschmid]

cschmid, you are correct in that assumption, i see it more every day, in fact i am doing more every day, and we stop at the new installs, we let the contractors handle any new service installs and any other work that we are not qualified for, we do primarily lighting and receptacle
loads, and some room modifications, but they ask for more everyday.

we need the proper training and the know how, to appply the new codes, however, mgmt looks for cheaper ways to do the work, i look for qualified, conscientious contractors to help me do my job.

I am unfortunately right..I do not agree with it..Yet the older I get the more prevalent it becomes..

I think one of the major issues that acerbates the whole situations is world wide free trade..Like we want stuff cheap so in order to keep it cheap and corporate Americas profits high we out source to place like India, Taiwan, ect..In these country's 35 to 50 dollars a month is fantastic wages now they might make 100 per month..So as long as we by from the Internet and other countries who living income is below poverty levels we will continue to decline and we will have to adjust our living styles to resemble other countries..

 

[realolman]

.There is no wasted power in running separate neutrals....

Wouldn't the power lost as heat generated by current through the resistance of 2 neutral wires be more than the power lost through heat generated by the vectorially added currents running through the resistance of 1 wire?

It seems to me there would be resources wasted in the manufacture, distribution, and installation of the "extra" wire. There could potentially be a lot of "extra" wires.

I agree that much of what is done in the name of safety is spawned in the interests of dumbing down ( read lower paying ).

I don't see me as being a contributor to the environmental damage caused by corporate America raping the earth..I see it just the opposite if corporate America wanted me to be environmentally friendly they would make going green affordable..This is a whole new issue..Like some of the process for using sustainable resources are more toxic then the regular process..yet this is an issue for a different topic..

I think we all need to try to do our part... I think energy and pollution is the biggest issue facing the inhabitants of this beautiful ol' planet today. And I think it's very serious.

What to do?

I don't know.... just try to do something .

 

[petersonra]

I am not too worried about the janitor wanna-be electricians. They are not as common as you might be led to believe.

A lot of skilled maintenance people are quite capable of making minor electrical repairs quite safely and do it every day. Pretending that it is impossible to safely make such repairs unless one has some kind of arbitrary license or supposed qualifications is just silly.

I don't see the need to hire an electrician to change light bulbs, replace ballasts, or any of a number of common maintenance type functions. There just are not enough "real" electricians out there to do the volume of that kind of work anyway.

The important thing is to get them trained enough that they can do this work safely, and for the most part, they are. You probably have as many unsafe electricians as you do unsafe maintenance workers.

 

[roger]

Wouldn't the power lost as heat generated by current through the resistance of 2 neutral wires be more than the power lost through heat generated by the vectorially added currents running through the resistance of 1 wire?

Realolman, you are correct, there would be more lost power in two wire circuits verses three wire circuits.

The illustration below is a modified drawing from Ed MacLarren.

It seems to me there would be resources wasted in the manufacture, distribution, and installation of the "extra" wire. There could potentially be a lot of "extra" wires.

And this is also true

I agree that much of what is done in the name of safety is spawned in the interests of dumbing down ( read lower paying ).

True, but that is not the only reason for "dumbing down" the code

I think we all need to try to do our part... I think energy and pollution is the biggest issue facing the inhabitants of this beautiful ol' planet today. And I think it's very serious.

And so do I, this old earth has just about taken all we can give her.

What to do?

I don't know.... just try to do something .

Every little bit helps.

Roger

 

[cschmid]

I do care about the environment maybe more than what has been displayed..

I do understand you arguments and I do agree to a point..But safety does come at a price and with MWBC this price is still changing..

I am not worried about janitor wanna be electricains..it is the good maintenance employees who decide they can move the light fixture and go to J-box open it up add a piece of conduit and box and fixture they have no clue about MWBC..I don't agree but it happens all the time..

 

[roger]

it is the good maintenance employees who decide they can move the light fixture and go to J-box open it up add a piece of conduit and box and fixture they have no clue about MWBC

So you say a "good electrican" will see one neutral and multiple ungrounded conductors in this box and not have a clue that he his dealing with a MWBC, I guess you and I have different opinions of what a "good electrican" is.

Roger

 

[M. D.]

....And so do I, this old earth has just about taken all we can give her....
Roger

something to think about....
from the prologue to Jurassic Park by Michael Crichton:

You think man can destroy the planet? What intoxicating vanity. Let me tell you about our planet. Earth is four-and-a-half-billion-years-old. There's been life on it for nearly that long, 3.8 billion years. Bacteria first; later the first multicellular life, then the first complex creatures in the sea, on the land.....

.......Earth has survived everything in its time. It will certainly survive us. If all the nuclear weapons in the world went off at once and all the plants, all the animals died and the earth was sizzling hot for a hundred thousand years, life would survive, somewhere: under the soil, frozen in Arctic ice. Sooner or later, when the planet was no longer inhospitable, life would spread again. The evolutionary process would begin again. It might take a few billion years for life to regain its present variety.....

 

[cschmid]

So you say a "good electrican" will see one neutral and multiple ungrounded conductors in this box and not have a clue that he his dealing with a MWBC, I guess you and I have different opinions of what a "good electrican" is.

Roger

Did I say Electrician..I said maintenace person..