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Old 03-24-2020, 04:39 PM   #21
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What do you do with a/c or 240 appliance circuits?
Those require 2-pole breaker‘s, as you know. I was only talking about multiwire branch circuits.

When I change out a panel, I often do it based off of a picture that the customer sent me. That picture will show me the 240 V loads like electric stoves or AC condensing units. So I will be sure to have those breakers, plus a small amount of others just in case.

But what I sometimes find is five or six multiwire branch circuits after I’m on the job changing the panel. So it’s easier to stock 50 cent handle ties than all those 2-pole 15 and 20 amp breakers.
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Old 03-24-2020, 05:11 PM   #22
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Around here there are so many different panels it is a royal pita to keep stocked with all of them. We also try and get the brand before we get there but sometimes we don't know we are going to need breakers.

BTW, I knew you knew about the dp breakers- that why when you said that handle ties keep your stock down I was wondering how it did that when dp's are sometimes needed.
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Old 03-24-2020, 06:21 PM   #23
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cheaper than a 3 pole breaker but absolutely ridiculous for a single handle tie.
12 gage THHN is about $00.14 per foot. With a 100 foot run it would be less money to add 2 neutrals than it would be to buy the handle tie. It might even be advantageous if you need to work on one circuit without shutting down the other 2.
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Old 03-24-2020, 10:10 PM   #24
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12 gage THHN is about $00.14 per foot. With a 100 foot run it would be less money to add 2 neutrals than it would be to buy the handle tie. It might even be advantageous if you need to work on one circuit without shutting down the other 2.
That's why this rule exists, to sell copper.
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Old 03-24-2020, 11:07 PM   #25
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cheaper than a 3 pole breaker but absolutely ridiculous for a single handle tie.
12 gage THHN is about $00.14 per foot. With a 100 foot run it would be less money to add 2 neutrals than it would be to buy the handle tie. It might even be advantageous if you need to work on one circuit without shutting down the other 2.
True, but if the wire Is already there and connected my time is going to cost a lot more than $40. Compared to what it would take to pull the wire, open up boxes, and connect everything. At 14 cents per foot(200' total) your cost is $28 before labor. If you haven't pulled the wire yet then I would just add two neutrals and call it A-day.

Edit: I also run multi wire branch circuits sometimes for the safety aspect on boilers or equipment. They require multiple 120v circuits, And it's nice if a circulation pump trips the whole boiler shuts off and doesn't try to run. Insted of only relying on a flow switch.
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Old Yesterday, 02:33 AM   #26
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12 gage THHN is about $00.14 per foot. With a 100 foot run it would be less money to add 2 neutrals than it would be to buy the handle tie. It might even be advantageous if you need to work on one circuit without shutting down the other 2.
Yes but if you're running a large amount of circuits you need bigger/more pipes which adds up and also takes up more space. I share neutrals whenever possible because it's no less safe when done properly and makes for a more streamlined installation.

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Old Yesterday, 05:46 AM   #27
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Edit: I also run multi wire branch circuits sometimes for the safety aspect on boilers or equipment. They require multiple 120v circuits, And it's nice if a circulation pump trips the whole boiler shuts off and doesn't try to run. Insted of only relying on a flow switch.
That's a good idea, kind of uses the breaker common trip as an interlock.

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Old Yesterday, 05:51 AM   #28
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12 gage THHN is about $00.14 per foot. With a 100 foot run it would be less money to add 2 neutrals than it would be to buy the handle tie. It might even be advantageous if you need to work on one circuit without shutting down the other 2.
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Yes but if you're running a large amount of circuits you need bigger/more pipes which adds up and also takes up more space. I share neutrals whenever possible because it's no less safe when done properly and makes for a more streamlined installation.
Both good points, if the savings of neutrals keeps you from tipping from 3/4" to 1" or etc. that's of value. Of course if you avoid shared neutrals, you are safe from handle tie gouging, AND from the dreaded harmonics.
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Old Yesterday, 09:28 AM   #29
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"Yes but if you're running a large amount of circuits you need bigger/more pipes which adds up and also takes up more space. I share neutrals whenever possible because it's no less safe when done properly and makes for a more streamlined installation."

I was just brain storming this scenario. I think it would be totally impractical to run multiple neutrals. They would need to be paired and probably require wire markers just to keep the inspector happy. I think it would be safer with just one neutral.

"True, but if the wire Is already there and connected my time is going to cost a lot more than $40. Compared to what it would take to pull the wire, open up boxes, and connect everything. At 14 cents per foot(200' total) your cost is $28 before labor. If you haven't pulled the wire yet then I would just add two neutrals and call it A-day."

I know .. It would be way more labor both at the point of connection and at the panel when you did the makeup. Not to mention 3 spools of white wire added to your wire dolly when you had to pull wire.

"Both good points, if the savings of neutrals keeps you from tipping from 3/4" to 1" or etc. that's of value. Of course if you avoid shared neutrals, you are safe from handle tie gouging, AND from the dreaded harmonics."

It would help with harmonics. Good point. I’m looking at this from a maintenance stand point. It would really disrupt operations in an office setting if you had to shut down 3 circuits just to replace a ballast or receptacle. If you had to you could remove the handle tie and shut off just one breaker do your repair and replace the handle tie when you are done. The only downside to having one neutral would be in a case where you were feeding computers. Open or floating neutrals can really damage computers or electronics in general. Having individual neutrals would at least save the equipment on the other 2 circuits.
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Old Yesterday, 11:55 AM   #30
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When it comes to lighting and multiwire circuits, a lot of the shutdown all three circuits issues have been mitigated by the quick connects either provided by the manufacturer or added in to the light fixture by subsequent installer of new led light equipment. You all install the little orange disconnects each time you change out a ballast or driver right? ............... Of course you do, silly of me to bring this up..............................
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Old Yesterday, 01:34 PM   #31
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Both good points, if the savings of neutrals keeps you from tipping from 3/4" to 1" or etc. that's of value. Of course if you avoid shared neutrals, you are safe from handle tie gouging, AND from the dreaded harmonics.
I realize this is the NEC section, however as a Canadian I am fortunate that our code does not coddle our electricians by requiring handle ties for MWBCs.

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Old Yesterday, 01:49 PM   #32
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I realize this is the NEC section, however as a Canadian I am fortunate that our code does not coddle our electricians by requiring handle ties for MWBCs.

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Old Yesterday, 01:51 PM   #33
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Good point. I’m looking at this from a maintenance stand point. It would really disrupt operations in an office setting if you had to shut down 3 circuits just to replace a ballast or receptacle. If you had to you could remove the handle tie and shut off just one breaker do your repair and replace the handle tie when you are done.

In some ways that can be more dangerous than working live.
There can be current on the neutral, and since "the breaker is off" it gives the impression you can't get shocked.

@macmikeman suggestion of the disconnect at the fixture would be best.
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Old Yesterday, 01:53 PM   #34
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That's ok with us. We give mulligans in order to keep things fair.

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Mebbe .... but a roll of loonies to the head hurts more in CAN $$
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Old Yesterday, 05:09 PM   #35
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In some ways that can be more dangerous than working live.
There can be current on the neutral, and since "the breaker is off" it gives the impression you can't get shocked.

@macmikeman suggestion of the disconnect at the fixture would be best.
Yes so true. I was being a bit macho in my statement. When ever possible a multi wire branch should be shut down completely before attempting to make repairs. Spices / wire nuts & lever-nuts alike can come lose and if anything inside that JB was still hot you run a very good risk of getting shocked.
Offices, labs or what ever. Kill the power to all sources including foreign voltages and make sure your safe.
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Old Today, 07:09 PM   #36
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I can tell you that the EC's that work regularly in the jurisdiction I work for, They all use handle ties or multipole breakers ! They know they will get the red for not doing so.
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Old Today, 07:37 PM   #37
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I have seen a lab full of VERY expensive test equipment go up in magic smoke before.
Connection to neutral bus came off and bus was not bonded to ground due to being a sub panel.
All test equipment became voltage dividers and put a little voltage here a lot there, sparks here a lot of smoke there. Six figures of damage.

Yes I know just an open neutral can do the same thing but this is an example for people that lift a neutral on a MWBC
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Old Today, 07:41 PM   #38
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I can tell you that the EC's that work regularly in the jurisdiction I work for, They all use handle ties or multipole breakers ! They know they will get the red for not doing so.
And I just recently had an inspector ask why there were two breakers marked Master bath receptacle with a handle tie between. Had I ignored the handle tie requirement I wonder if he would have noticed.

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