Dedicated Neutrals

[sckby5]

So I'm wondering, I am going to be re wiring my house shortly. Here's the situation, do I pull separate circuits and separate neutrals for everything. I.E., I have two bedrooms. Do I put the lighting & power in room 1 & 2 on two separate lighting circuits with the same neutral and same for power. Or pull dedicated neutrals for each branch circuit, so two lighting circuits and two power circuits, with four neutrals? Just curious if either situation would affect energy consumption, as far as utility bill every month. And also would either help against protecting the dimming of the lights situation you get when you turn on a vacuum or something similar?
THanks

 

[Dennis Alwon]

Have you ever wired a house before? The reason I am asking is there is a lot to know and trying to do it alone may be hard.

If I were wiring a house I would always use one neutral with one feed and never use a multiwire branch circuit because of the need for AFCI.

If there are 2 bedrooms I usually will put the receptacles on one circuit for both rooms and the lights in the bedroom on with the hall lighting and other areas that need afci. So I would have 2 circuits total that would feed the bedroom recep & lightig.

 

[Little Bill]

So I'm wondering, I am going to be re wiring my house shortly. Here's the situation, do I pull separate circuits and separate neutrals for everything. I.E., I have two bedrooms. Do I put the lighting & power in room 1 & 2 on two separate lighting circuits with the same neutral and same for power. Or pull dedicated neutrals for each branch circuit, so two lighting circuits and two power circuits, with four neutrals? Just curious if either situation would affect energy consumption, as far as utility bill every month. And also would either help against protecting the dimming of the lights situation you get when you turn on a vacuum or something similar?
THanks

If you are rewiring than you are making changes to an existing installation. You would IMO and by code need to install AFCI breakers for the bedrooms. Unless you buy an AFCI made for MWBC (can't use a shared neutral on regular AFCI) you will need to wire each room on separate AFCI circuits. I don't think you will see any difference in power consumption either way. If you had long runs, a MWBC would lessen the voltage drop but I don't like them in residential.


Sorry Dennis, we done it again!

 

[sckby5]

Yes, I have rewired houses before.
Been a commercial/industrial electrician for the past 11yrs.
Completely forgot about the need for the AFCI now when upgrading wiring.
That basically answers my question then.

 

[Little Bill]

...

If there are 2 bedrooms I usually will put the receptacles on one circuit for both rooms and the lights in the bedroom on with the hall lighting and other areas that need afci. So I would have 2 circuits total that would feed the bath recep & lightig.

Dennis, wouldn't that be 3 circuits total? You said 1 circuit for recps. both rooms. 1 circuit for lights, both rooms and misc, then you would need 1 20A for the bath recep. Right?

 

[Mgraw]

I only used a MWBC in residential for the dishwasher and garbage disposal circuits. I have run some 12/2/2 for longer runs. Square D came out with a paper on AFCIs and MWBCs a few years ago. Here is a link.
http://static.schneider-electric.us... Circuit Interrupters-AFCI/0760DB0203R902.pdf

 

[kwired]

If you do not want lights to dim when turning on a vacuum or any heavy load, do not put the lights on the same circuit as the receptacles.

There are several ways to wire these rooms all that are code compliant. It is up to designer/installer to decide what meets needs outside of code issues, as well as balance the cost with what is acceptable.

You could put any number of bedrooms on one branch circuit and be code compliant or you could run individual branch circuit to every outlet in those same rooms and still be code compliant. There will be a considerable cost difference between the two installations, as well as difference in performance abilities.

 

[Dennis Alwon]

Dennis, wouldn't that be 3 circuits total? You said 1 circuit for recps. both rooms. 1 circuit for lights, both rooms and misc, then you would need 1 20A for the bath recep. Right?

Well the op never mentioned a bath room but yes, you would need a cir. for that also.

Since the code allows us to install a standard breaker in bathrooms I tend to wire the bath lights from multiple baths together-- if they are fairly close-- This is all preference and has nothing to do with NEC. I could , more than likely, install both bedrooms recp and lights as well as the bath lights on one AFCI branch circuit.

 

[Little Bill]

(quote Dennis)
If there are 2 bedrooms I usually will put the receptacles on one circuit for both rooms and the lights in the bedroom on with the hall lighting and other areas that need afci. So I would have 2 circuits total that would feed the bath recep & lightig.

I only mentioned bath because you said bath recep & light. You might have meant to say bedroom.

 

[Dennis Alwon]

(quote Dennis)
If there are 2 bedrooms I usually will put the receptacles on one circuit for both rooms and the lights in the bedroom on with the hall lighting and other areas that need afci. So I would have 2 circuits total that would feed the bath recep & lightig.

I only mentioned bath because you said bath recep & light. You might have meant to say bedroom.

I did--oops I will change it. Thanks

 

[jumper]

Dennis, do you ever run a MWBC in a dwelling unit? Possible trick question.

 

[Little Bill]

I did--oops I will change it. Thanks

Your welcome! I was just confused and wanted to re-assure myself.

 

[kwired]

Dennis, do you ever run a MWBC in a dwelling unit? Possible trick question.

If you have an electric range or electric dryer you have MWBC. Some appliances may not require a neutral but generally the typical 125/250 outlet is installed anyway just in case an appliance gets installed at a later time that does need a neutral.

 

[mivey]

If there are 2 bedrooms I usually will put the receptacles on one circuit for both rooms and the lights in the bedroom on with the hall lighting and other areas that need afci. So I would have 2 circuits total that would feed the bedroom recep & lightig.

That's what I would do for others on a bid. The only time I have put MWBC in a residence was in a detached shop.

I like to have multiple circuits in a room so I do a little more leap-frogging for my own use. Doesn't really pay in situations where the customer is trying to get the lowest cost. For those that can appreciate it (like my own stuff) I also put heavy-duty receptacles in high use areas for vacuum cleaners, hair dryers, and other stuff that gets plugged and unplugged a lot.

For my own stuff, I would not be the low bidder as I tend to over-build. But it makes me happy so it is worth it to me. :grin:

 

[jmellc]

I don't like MWBC's, especially now with double pole breaker being required & with nearly everything in a house requiring AFCI. Losing a neutral means trouble on 2 ckts instead of 1. Adds to confusion downline if ckts split off to 2 wire cable downline of HR box. I didn't even know you could get AFCI brkrs set up for MWBC's. News to me.

 

[LarryFine]

I prefer separate lighting and receptacle circuits, too, for performance as much as economics.

I like 20a receptacle circuits and 15a lighting circuits.

Dennis, do you ever run a MWBC in a dwelling unit? Possible trick question.

I do, with every house. The house itself.

 

[mivey]

I do, with every house. The house itself.

Is that a branch circuit?

 

[hurk27]

Dennis, do you ever run a MWBC in a dwelling unit? Possible trick question.

I do but I cheat, Indiana doesnt require AFCI's

 

[jmellc]

I prefer separate lighting and receptacle circuits, too, for performance as much as economics.

I like 20a receptacle circuits and 15a lighting circuits.

I do, with every house. The house itself.

I separate lights & receptacles as much as possible. That way, if you lose lights, you still have receptacles for lamps. Lose receptacles, you still have lights. Either way, makes your troubleshooting easier.

 

[LarryFine]

Is that a branch circuit?

From the transformer's point of view, yes.