2 circuits on a 3 wire

I have never heard of running a dedicated circuit to heat section of fan. Can you direct me to that code? So I can educate myself And by the way, with two seperate circuits landing in the same switch, I think you need to put both those circuits on the same breaker. This requires a two pull breaker, (240v) wich means you can tie your two breakers together, or trade out for a two pull. I cant believe the inspector missed that one. Oh well, I guessed he passed ya off. Good work on your project.

LOL

"I have never heard of running a dedicated circuit to heat section of fan. Can you direct me to that code? So I can educate myself."

Sorry that you haven't!

2008 NEC: Bathrooms are required to have 20A circuits.

The specific code is probably not as important, but more the principal involved, so pull up a seat

This particular heat element for the PANASONIC FV-11VHL2 draws 1425Watts. A 15A circuit has a total capacity of 1800watts but the safe capacity is 1440watts. A 20A circuit has a total capacity of 2400watts with a safe capacity of 1920watts. The manufacturer recommends 20A circuits.

So, now a days, it makes more electrical sense to put high wattage devices on their own dedicated circuits: microwaves, dishwashers, particle accelerators, stoves, radiant floor heat, bathroom heat because in many cases, the appliance approaches the safe capacity of the device.

Besides, this product has HEAT, LIGHT, NIGHT LIGHT AND the FAN in the same unit and it just draws too much juice for one circuit-one 20A circuit; but more importantly, and i knew this, the inspectors at City Hall made this a requirement on my plans, before they approved them and I began the work.

Also, the branch circuit that supplies the fan and light, also supplies the GFCI outlet over the sink and the vanity light. If EVERYTHING were on a 20A circuit, including the HEAT and someone plugs in a hair dryer-THE LIGHTS AND EVERYTHING are going OUT !!! lol

"And by the way, with two seperate circuits landing in the same switch, I think you need to put both those circuits on the same breaker. This requires a two pull breaker, (240v) wich means you can tie your two breakers together, or trade out for a two pull."

Absolutely NOT! For one thing, in my simple residential bathroom project, the separate circuits are exactly that-SEPARATE; Separate romex, Separate Breakers and Separate Switches! 20A separate switches-as a matter of fact!

I used the Pass & Seymour PS81120I 20A combination switch which has this nifty (re-usable) tab to split the circuit; I used the BIG switch for the heat and the 2 top switches for the light and night lite. I have them installed with the big switch on the bottom It is detailed in my wiring diagram in a previous post

The fan (29watts) is controlled by a Lutron MA-t51-IV timer. The 2 decora styled controllers fit nicely in a 2 gang box. The 3 switch in the one gang was a life saver otherwise I'd have to put in a 3-gang monstrosity to house a fan timer, light and night light and a separate switch for a separate circuit; most triple switches that i found at Home depot or Lowes were all on the same circuit.

Dude, The Code Enforcement Division of any municipality would never just "PASS ya OFF" on an electrical matter where the main purpose of an electrical inspection is to save lives through fire protection. These guys know their ****, unlike me

If you are interested in Online Access to NFPA 70®: National Electrical Code® (NEC®) Softbound, 2008 Edition you can visit the NFPA website, create a free account and pour through the 2008 NEC for the specific code.

Another excellent reference is wiring simplified, 42nd edition.

and lastly, this is so very helpful for me...Black and Decker: Complete Guide to home wiring

Thanks for being interested ! This is a great forum!

Cheers

Good Job! I just wish the licensed electricians that wired up the bathrooms in my home were able to realize what you have.

kok328 said:

Good Job! I just wish the licensed electricians that wired up the bathrooms in my home were able to realize what you have.

Click to expand...

Aw Shucks! I installed another panasonic product downstairs bathroom but without the ceiling heat cuz i had installed floor heat (nice). The biggest reason for going panasonic was that it is sooooooooooo quiet!

I used the heat part this morning for the first time during a shower and it was awesome!!!

cheers!

BTW, with this and other forums: YOU CAN DO IT ALL YOURSELF!!!!!!!!!!!!

Look, in my reply, I said (I think). Now what had me concerned was this talk of phasing wires and sharing neutrals. It is not a code issue to have two seperate circuits from seperate wires in the same box on seperate breakers like I (thought) it was. However at no point along those circuits can the neutrals touch. I and others like me volunteer ourselves to assist people in a safe way. I am simply trying to do that for you. Are your neutrals touching? And no code exists, or ever has, that requires a dedicated circuit for your fan/heater. My idea for you was one any electrician would have had. One 12-2 for the entire fan/heat/lite. And of course a dedicated 12-2 for the gfi plug, and vanity light. This was just a suggestion that may have made things a little easier for you. I did not intend to offend you, I was genuinely interested in a code reference because I would have learned a new one. Today I checked and there is not one for that. And you would be amazed at what some other people have done that these inspectors that I have been dealing with for over ten years have passed off before. I sorry to be offensive, Dan

Wish I had a 20A/12AWG circuit in my bathroom to accomodate all that plus a hairdryer and a heated towel bar. 15A/14AWG just won't cut it.

A 15a 1800w circuit has a safe rating of 1800 watts
A 20a 2400w circuit has a safe rating of 2400 watts
= in both cases provided it is not something that is a continous load
Actually there is a lot of leeway in what the wiring can handle
The breaker will almost always kick off before the wiring has a problem so long as the correct gauge/breakers are used
There isn't an 80% rule for loading, unless it is something with a motor - AC etc or something that will be a continous load - more then "x" hours
I load all of my light circuits to the full rating of the breaker

Under NEC 2008 a multi-wire circuit is required to have a double breaker so that both hots shut off. This is the preferred method as it automatically puts the 2 hots on opposite sides - "out of phase"

12-3 = 2 hots & a neutral & a ground
If fed out of phase the load blances against each other on the neutral
IE 15a on one, 10a on the other - neutral carries 5a

If on the same phase the loads ADD for the neutral
IE 15a + 15A = 30a on the neutral - TOO MUCH!!

The other option is to have 2 single breakers & they must have a tie bar - so both shut off

The dedicated 20a bathroom circuit can be shared among bathrooms
So long as it feeds only outlets in the bathrooms & only the bathrooms
I don't recommend it
Running a dedicated circuit to high use appliances is an excellent choice
In many cases the Mfg requires it
There is wording the NEC requiring fixtures to be installed per Mfg instructions
Unfortunately some Mfg's have no clue, some lean very much towards extreme safety - afraid of legal problems - lawsuits

triple D said:

Look, in my reply, I said (I think). Now what had me concerned was this talk of phasing wires and sharing neutrals. It is not a code issue to have two seperate circuits from seperate wires in the same box on seperate breakers like I (thought) it was. However at no point along those circuits can the neutrals touch. I and others like me volunteer ourselves to assist people in a safe way. I am simply trying to do that for you. Are your neutrals touching? And no code exists, or ever has, that requires a dedicated circuit for your fan/heater. My idea for you was one any electrician would have had. One 12-2 for the entire fan/heat/lite. And of course a dedicated 12-2 for the gfi plug, and vanity light. This was just a suggestion that may have made things a little easier for you. I did not intend to offend you, I was genuinely interested in a code reference because I would have learned a new one. Today I checked and there is not one for that. And you would be amazed at what some other people have done that these inspectors that I have been dealing with for over ten years have passed off before. I sorry to be offensive, Dan

Click to expand...

My goodness. Please don't feel like you were being offensive, My tone is a little stilted in my writting style. Excuse me

The different circuits do not share neutrals.

The only code i could possibly think of would be not to over load a circuit to capacity which is something like not exceed the wattage capacity for a given rated circuit....now I am interested on what NEC codes apply to my project.

Now I have another project

cheers!

DaveyDIY said:

The dedicated 20a bathroom circuit can be shared among bathrooms
So long as it feeds only outlets in the bathrooms & only the bathrooms
I don't recommend it

Click to expand...

Lemme See, I came across this situation when planning this 20A circuit and whether or not this circuit could supply the outlet, the small vanity lights on one branch, and the Light(s) and fan in the ceiling.

Again, I had to plan the projected wattages for this circuit.

A dedicated 20A circuit is required for all bathroom receptacles, unless the circuit ( which still must serve only bathroom loads) supplies only one bathroom. In this case, the 20A circuit may serve the lighting outlets as well as the receptacle within the one bathrrom Thus, you may supply any or all bathroom receptacles ( in however many bathrooms) on a 20 a circuit, or all the load, but in only a single bathroom, on a similar circuit.

Ok, I'm lost now (not really) but, you see my point.

DaveDIY says:
"12-3 = 2 hots & a neutral & a ground
If fed out of phase the load blances against each other on the neutral
IE 15a on one, 10a on the other - neutral carries 5a
If on the same phase the loads ADD for the neutral
IE 15a + 15A = 30a on the neutral - TOO MUCH!!"

TripleD says:
"However at no point along those circuits can the neutrals touch. I and others like me volunteer ourselves to assist people in a safe way. I am simply trying to do that for you. Are your neutrals touching?"


Also, I'm curious, DaveDIY, why would you want to nusiance trip a non-offending circuit w/a two pole breaker?

Why would you run a 240V circuit when the destination is not 240V?
"Under NEC 2008 a multi-wire circuit is required to have a double breaker so that both hots shut off. This is the preferred method as it automatically puts the 2 hots on opposite sides - "out of phase""

I'm not totally sure what you mean by a "multi-wire circuit" but, I don't believe what vdotmatrix is doing, constitutes a multi-wire circuit or were you referring to my input on sharing a neutral. This still does not constitute a "multi-wire circuit".

Again, I'm curious and would like to be enlightened because if what your saying is true, I've got a ton of wiring problems in at least 4 out of 5 plants I work in.

kok328 said:

Ok, I'm lost now (not really) but, you see my point.

DaveDIY says:
"12-3 = 2 hots & a neutral & a ground
If fed out of phase the load blances against each other on the neutral
IE 15a on one, 10a on the other - neutral carries 5a
If on the same phase the loads ADD for the neutral
IE 15a + 15A = 30a on the neutral - TOO MUCH!!"

TripleD says:
"However at no point along those circuits can the neutrals touch. I and others like me volunteer ourselves to assist people in a safe way. I am simply trying to do that for you. Are your neutrals touching?"


Also, I'm curious, DaveDIY, why would you want to nusiance trip a non-offending circuit w/a two pole breaker?

Why would you run a 240V circuit when the destination is not 240V?
"Under NEC 2008 a multi-wire circuit is required to have a double breaker so that both hots shut off. This is the preferred method as it automatically puts the 2 hots on opposite sides - "out of phase""

I'm not totally sure what you mean by a "multi-wire circuit" but, I don't believe what vdotmatrix is doing, constitutes a multi-wire circuit or were you referring to my input on sharing a neutral. This still does not constitute a "multi-wire circuit".

Again, I'm curious and would like to be enlightened because if what your saying is true, I've got a ton of wiring problems in at least 4 out of 5 plants I work in.

Click to expand...

It s a new change in NEC 2008
When you are running a multiwire circuit you are sharing the neutral between the 2 circuits. You do not have to go back & fix pre-existing wiring. In 2005 only the connected bar was required between the breakers.
But 2 problems were identified:
#1 People were not installing the bar, or it was removed
As a result the breakers couild end up on the same phase & the power doubles on the shared neutral from the 2 circuits
#2 One breaker could be shut off, the other left live
Since this is a shared neutral power could flow on the circvuits that is shut off via the shared neutral

A 240v breaker is now required to prevent this
You are not supplying 240v, you are supplying 120v to 2 different circuits & using a shared neutral

As long as you have 2 circuits & seperate neutrals you are fine
This is only for Multi-wire circuits that share a neutral
Neutrals from 2 different circuits in the same box should not touch
All of the grounds are supposed to be tied together in the box

Hope that clears it up?

I have 3 setups using multiwire circuits
Each one is fed w/a 20a 240v breaker, power goes to a 40a dual 120v timer
After the timer there is a seperate run of 12-2 (GFCI protected) to outlets in my front garden & around the house
My multiwire circuit is only 12" long as the timers are connected to my panel
I knew of the upcoming change for 2008 so I used the 240v breakers
It makes sense, if the breaker is shut off then I know all power in the timer is off

The code is always changing - updated every 3 years
The wording can be very hard to understand
I've been in discussions with electricians, Inspectors & others on certain aspects of the code. In some cases each one has a different view of what the code actually is saying

By code you can run a 20a 120v circuit - UF wire - 12" deep without conduit. So long as it is GFCI protected befor eit goes in the trench. I wanted to run 2 circuits in the trench (6" wide), both 20a GFCI protected. Everyone I ran it by said that was perfectly acceptable
My Inspector did not fully agree, he said I needed 12" between the circuits in the trench. So I ended up running conduit

kok328 said:

I'm not totally sure what you mean by a "multi-wire circuit" but, I don't believe what vdotmatrix is doing, constitutes a multi-wire circuit or were you referring to my input on sharing a neutral. This still does not constitute a "multi-wire circuit".

Click to expand...

A "multi-wire branch circuit" is the correct term for a shared neutral circuit.
This is two (or three in the case of a 3-phase MWBC) hots sharing one neutral where the line conductors are placed on different "legs" of the panel as Dave described.

Thanks Dave, now I understand.
So I guess the gist of it is, do not create a multi-wire circuit where you can not tolerate one circuit tripping the other.

Thanks Again.