mstrlucky74
Senior Member
- Location
- NJ
It also has the advantage that the 3-pole breakers are more expensive than 3 1-pole breakers and 1 3-pole handle tie.
I don't think it's much more expensive
Insualted Equipment Grounding Conductor
- Thread starter mstrlucky74
- Start date
- Status
I don't think it's much more expensive
Probably twice the cost, or more.
Most folks in this area shy away from MWBC on lighting circuits now with the "new" requirements. With the handle ties or a multi-pole breaker, a short in any fixture or circuit or a need to turn off only one circuit by means of the breaker results in a loss of a lot of light.
With a 277v system you can end up with a whole bunch of fixtures that go dark due to one ballast shorting.
With a 277v system you can end up with a whole bunch of fixtures that go dark due to one ballast shorting.
- Occupation
- Licensed Electrician
Stupid, stupid new rule. One code change makes a hundred years of safe wiring a bad choice instead of an elegant, cost effective one.
- Location
- Massachusetts
Yes, changes made to help the unqualified. It will only get worse, one way or the other I only have 4 more code cycles to worry about.
mstrlucky74
Senior Member
- Location
- NJ
So using a 3p breaker for 3 separate circuits(as in this case) is a MWBC,correct? They share the same neutral.
if it were one motor utilizing a 3p breaker it would not be a MWBC.
i thought this was a good explanation although very basic for many of you.
http://www.homeinspector.org/resources/journals/Multiwire-Branch-Circuits.pdf
if it were one motor utilizing a 3p breaker it would not be a MWBC.
i thought this was a good explanation although very basic for many of you.
http://www.homeinspector.org/resources/journals/Multiwire-Branch-Circuits.pdf
Last edited:
Yes.
There are other instances of is and not, but no need to complicate the discussion.
fmtjfw
Senior Member
- Location
- Fairmont, WV, USA
With handle ties on 3 1-pole breakers it is not likely that a single breaker tripping would trip either or both of the other two breakers. The trip-free feature of the breaker that tripped would probably not have enough energy applied to the handle for that to happen.
No code rule against MWBC that I know of.
90.1 Purpose.
(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.
Handle ties are practical and add a level of safety.
I think the issue being called stupid is the requirement for handle ties... but there is nothing preventing the use of a wall switch to de-energize only one branch of the MWBC.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
And that would be fine to the extent that even an inexperienced electrician should not be using that switch to deenergize the circuit before working on it.
- Location
- Massachusetts
Handle ties are to aid the idiots doing electrical work. They make servicing MWBCs much more of a problem. It was hard enough trying to turn off a single 277 volt lighting circuit due to the large number of fixtures connected to it. Now it is three times as many fixtures.
It also meant we could no longer make a MWBC out of say circuits 1, 10, and 17 which was very common, safe and handy.
It was unnecessary change with no real substantiation provided.
fmtjfw
Senior Member
- Location
- Fairmont, WV, USA
Handle ties only cost a few bucks. I once saw the same electrician open the MWBC neutral on 120/208Y and blow up about 6 electronic items twice in the span of 2 weeks. He was a grandfathered master electrician and was convinced he knew everything there was to know. 90% of the buildings he worked had MWBC of 120/208 and 277/480. Handle tying all the MWBCs in the building would have cost less than what he destroyed.
It would also prevent him from being shocked on a floating neutral (which he richly deserved).
Unfortunately there are a lot of electricians who quit learning on or before they completed their apprenticeship or formal training. And there are a lot of electricians working today who don't understand MWBCs, Sad, But True.
- Occupation
- Licensed Electrician
:thumbsup::thumbsup::thumbsup:
- Location
- Massachusetts
The cost of the handle tie is not the issue.
And this means what? That because he was an idiot the rest of us should have to change how we work?
Changing code rules is no way to fix the problem of people not knowing their job.
fmtjfw
Senior Member
- Location
- Fairmont, WV, USA
OK, so you make a MWBC out of 1, 10, & 17. How am I, a person who understands MWBCs, supposed to know what to turn off when I need to cut a shared neutral to add a connection? I might wonder about the intelligence of an electrician who would use such a breaker "grouping".
Fixtures to turn off: 277 is most likely florescent lighting. I suppose that now you are going to tell me that the use of little pluggable disconnects in fluorescent fixture is also dumbing down the trade. If not, they are the solution to not turning off any of the lamps except the one(s) you are working on.
- Location
- Massachusetts
Do you own a meter? Do you know how to use it?
Wow, insulting a very large group of electricians you have never met, a bold move.
Well, they are a dumbing down of the trade and the fact is I don't feel comfortable plugging in and unplugging these cheesy little disconnects on live circuits particularly 277 volt ones. Once these things start aging and becoming brittle we will see a rise in burn injuries. I prefer to kill the power to the fixture. I might get behind the concept if they required a switch of some sort in place of the junk plastic plugs.
fmtjfw
Senior Member
- Location
- Fairmont, WV, USA
Goodbye
Goodbye
What do you think? I am getting tired of your gratuitous insults.
I consider it unintelligent to leave a trap for the next electrician in the form of a MWBC scattered through out a panelboard.
Then I guess that you don't follow the NFPA70E Rules when working on a hot circuits. There is generally not enough energy at such a disconnect to burn through a set of goatskin protectors and meterman's rubber gloves.
Unfortunately, you are immune to the "ignore list" function, so I'll do it manually.
Goodbye
What do you think? I am getting tired of your gratuitous insults.
Wow, insulting a very large group of electricians you have never met, a bold move.
I consider it unintelligent to leave a trap for the next electrician in the form of a MWBC scattered through out a panelboard.
Then I guess that you don't follow the NFPA70E Rules when working on a hot circuits. There is generally not enough energy at such a disconnect to burn through a set of goatskin protectors and meterman's rubber gloves.
Unfortunately, you are immune to the "ignore list" function, so I'll do it manually.
Last edited:
- Occupation
- Licensed Electrician
And I go back to this....
90.1 Purpose.(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.
The stated purpose is fulfilled without any rule for using handle ties or three pole breakers. MWBCs present no hazard to anyone using them. The '08 code change moved beyond that purpose to safeguarding bozos working on them. Yea, that's what we need more rules geared toward guys like the fella in your example. Let's do all we can to keep them afloat in the trade.
I used to bounce MWBC all over the panel, I didn't, and still don't see it as a problem.
You are free to question my intelligence, I won't be offended. I don't think it is much above average, if at all. I struggle with basic math, couldn't tell the first thing about the magic that makes electrical stuff work once the discussion moves beyond circuitry and wires, shoot man, I can't make a post without using spell check on words with more than five letters.
I can figure out which breakers I need to turn off when working on MWBCs. Depending on where I am working on the circuit I may only need to turn one breaker off and still keep me and any equipment safe. Stupid handle tie rule makes that impossible.
I don't question anybody's intelligence if they don't know which breakers to turn off just because they are not grouped. I do question their qualifications.
I resent code mandated training wheels like 210.4(B). They weaken the quality of the trade rather than elevating the importance of education, training, and skill.
- Location
- Massachusetts
Interesting, you have no problem questioning my intelligence and the intelligence of a great many other electricians but you feel insulted if I ask you if you have a meter.
It seemed like a fair question as you stated you did not know how to identify circuit conductors.
Well you guess wrong, but there is no requirement to wear gloves or PPE when there are no live exposed parts. If it was 'hot work' there would be no allowance to do it PPE or not. If I was to break safety rules the company I work for will either give me unpaid time off or terminate me.
Do you know what a experiance mod rating is? The company I work for has a very low Mod rating and they take safety very serious.
http://en.m.wikipedia.org/wiki/Experience_modifier
- Location
- Illinois
- Occupation
- retired electrician
Why should that become a code rule placing a burden on the "real" electricians?
The handle tie rule accomplished exactly the opposite of what it was intended to do. That is there are more lighting circuits worked on while energized now that before that rule.
- Status