Split duplex receptacles for lighting

[Possum]

This post in another lighting thread by Charles (in GA) just happened to come up when I have been contemplating my light setup. - http://www.garagejournal.com/forum/showpost.php?p=1133826&postcount=19

So school me on this. I would like to use split receptacles mounted on the ceiling with plug in type 4' fluorescent fixtures in pairs. I assume this could be controlled by two switches so I can use half the lights if desired but still have decent light spacing instead of losing a whole bank of lights. Are these special receptacles? Can this be wired up with 12-3 or 14-3 NM wire? If so can you use one breaker for both hots? Any problems doing this and using 3 way switches? Any better alternatives?

Thanks.

 

[mrb]

not special receptacles, you just break off the tab tying the two hot sides together.

yes they can be on the same breaker.

if using 3 way switches, you need to plan your arrangement of cables. remember all conductors of the circuit have to be in the same cable, if you need a 5th wire you cant run a seperate cable.

you can go breaker -> 12(14)/2 -> switchx2 ->12(14)/3->receptacles

for 3 way you would do as above but run a second 3 conductor cable over to the second switch. to feed one end of the 3way setup and take the load off the other end you would have a real mess of cables

 

[Falcon67]

I think that's called a Multi-wire branch circuit with a split wired receptacle and shared neutral. What a mouth full. Better read up on the allowable.

http://www.inspectapedia.com/electric/multiwir.htm

I'm not touching the 3 way switch deal LOL

 

[hillbilly1]

I think that's called a Multi-wire branch circuit with a split wired receptacle and shared neutral. What a mouth full. Better read up on the allowable.

http://www.inspectapedia.com/electric/multiwir.htm

I'm not touching the 3 way switch deal LOL

If your using only one circuit to supply it, it is not a multi wire branch circuit, it is just a plain ol' switch leg. Both can be switched. Take care to break the tab between the brass screws only. That is where your black and red will terminate.

 

[Possum]

Thanks fellas!

 

[Charles (in GA)]

One single pole (120v) circuit breaker supplying two regular light switches, each switch supplies a hot wire (one black, one red for easy id) and these supply the top and bottom of a duplex receptacle that has the tab broken out of the hot (brass) side of the receptacle. The neutral runs to the silver side of the receptacle. The effect here is that you get a total of 20 amps shared between the two receptacles (top and bottom)

Other option is a Multi-wire circuit, use a double pole circuit breaker with the handles ganged together (240v breaker) and the two hot wires (red and black) run to a single double pole light switch (I suggest not using two separate switches for safetys sake, however I don't think it is forbidden by code). From the switch, the two hots run to the top and the bottom of a duplex receptacle with the tab broken out of the brass side, and the neutral runs to the silver screws. The effect here is 20 amps or (15 amps depending on the breaker) available at each of the two outlets on the duplex receptacle. 20 amps top, and 20 amps bottom.

Note on multi-wire, you have to pigtail the neutral, Wire in the box/wire out of the box/pigtail to the receptacle all wire nutted together. You must do this so that the removal of the receptacle will not interrupt the neutral downstream. Many people want to run the neutral to one screw and then off the other screw to the next outlet, not allowed with multiwire per code.

Also note that you can use a 20amp breaker to supply more than one 15 amp rated outlet, but if you use multiwire and split a receptacle and don't have but this one receptacle in the circuit, it must be a 20 amp rated receptacle if you intend to drive it with a 20 amp breaker.

Also, lighting is considered continuous by code and this means you cannot exceed 80% of a components capacity. If you use a 15 amp breaker, you are limited to 12 amps of load on the circuit. If you use 20 amp breakers, you are limited to 16 amps of load on the breaker, and no more.

Multiwire circuits must use double pole breakers with handled tied together (or two single pole breakers with the handles tied together (common trip).

Charles

 

[Possum]

Fantastic info.

Here is the plan - A 15 amp single pole breaker feeding 14-2 NM to a single double throw(or pole?) three way switch. I assume I can get a single double throw three way switch? From that switch a 14-3 NM leg to another single double pole three way switch across the shop and 14-3 NM leg feeding six ceiling mounted split duplex receptacles. These will power 12 - 4' 2 bulb T-8 fluorescent with electronic ballast rated at 120V 800 mA, or a total load of 9.6 amps on my available 12.

Sound good?

 

[gc427]

IMO I would use 12 ga wire and a 20 amp breaker with 15 amp receptacles.

The added cost of 12 ga wire and 20 amp breaker is minimal, but gives you flexibility to upgrade or run saws or other power tools without worrying about overloading the circuit.

JMO

 

[Possum]

These will be mounted up on the ceiling, so I don't think I will be plugging saws into them. I have wall mounted receptacles at least every 6' so I should be covered. Plus I have enough leftover 14 gauge to do this. It might be nice to put in a few double boxes in the ceiling in case I ever put an island type workbench in the area. I could put these on 12-2 with 20A non split receptacle and give them a dedicated breaker. That would be pretty nice come to think of it.......

I think this is the style switch I need - http://www.homedepot.com/Electrical...splay?langId=-1&storeId=10051&catalogId=10053 - kind of expensive. I am short on space in the box for the switches, which is why I am thinking this style of switch. It could be changed if needed.

 

[gatchel]

If you are planning 3-way arrangements on both lighting circuit feeds that switch is only 3-way on one of the toggles.

 

[Possum]

Yes I am. I wondered why it had the on/off markings on one of the switches! Looks like I need a 5243 switch like this - http://www.amazon.com/dp/B000ZOJL1U/?tag=atomicindus08-20 - even more expensive! Might be time to change that box out from a 3 space to a 4. No drywall yet so it won't be too difficult.

 

[Charles (in GA)]

Stick with 15amp and 14 gauge wire. With 6 wires on that switch, even making nice Z folds on every one of them, it would be real tough to get them to fold up and push the switch back into place upon installation. W/ 12 gauge wire you stand a good chance of breaking the switch applying the force to it needed to get it back into the box. 14 gauge will help alot in this.

Charles

 

[Possum]

Well - the lights are wired and working great. I ended up using two single throw three way switches at each location instead of double throw three way$$$. I also used the 14-3 NM for the feeder wire instead of 12-2. I took the advice of gc437 and added three receptacles on the ceiling on their own circuit.

It all went smoothly and I appreciate the expertise fellas.

 

[egdede]

Note on multi-wire, you have to pigtail the neutral, Wire in the box/wire out of the box/pigtail to the receptacle all wire nutted together. You must do this so that the removal of the receptacle will not interrupt the neutral downstream. Many people want to run the neutral to one screw and then off the other screw to the next outlet, not allowed with multiwire per code.

Charles

Always keep this in mind when working on older circuits: Something as simple as changing an old outlet can lead to a variety of different problems if a shared neutral is broken. (For example; 240 volts downstream.)

I turn my Mom's main off to do anything because, over the decades, a variety of dumb-asses have worked on her house. I have found outlets which were fed with a single hot wire and the neutral connection made by running a wire to a pipe.