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Ok so this may be a dumb question but I'm only 2 months into the trade and I'm having a hard time picturing and understanding the concept and purpose for switch legs and pigtails and when they are needed. I am currently roughing in gang boxes for outlets and lights that are whipped from switches. I am confused on when I need a neutral pigtail and when I need to just join them, wire nut them and tuck them in the box. Also when identifying the switch leg does that also get pigtailed. I'm confused. My coworkers are too busy to ever explain it to me. I hate having to do things that I don't understand. I want to know why I'm doing something and how the process works. I will attach a picture of an example.
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A simple switch does not need a neutral since the switch is interrupting the power feed only. You might have the neutrals in the switch box if that is where the power is run to. Sometimes the power is run to the fixture box first and then a single 2 wire cable is brought down. In that instance there is no neutral at all in the switch box.

You are required to have a neutral in a switch box now (at least in canada) because with new switches with electronics in them, like dimmers, they require a neutral for the electronics to work.

If it was a simple toggle switch, the neutrals are connected and pushed into the back
if its an electronic switch, the neutral is pigtailed to provide a conductor to connect to the switch
 

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Discussion Starter · #3 ·
A simple switch does not need a neutral since the switch is interrupting the power feed only. You might have the neutrals in the switch box if that is where the power is run to. Sometimes the power is run to the fixture box first and then a single 2 wire cable is brought down. In that instance there is no neutral at all in the switch box.

You are required to have a neutral in a switch box now (at least in canada) because with new switches with electronics in them, like dimmers, they require a neutral for the electronics to work.

If it was a simple toggle switch, the neutrals are connected and pushed into the back
if its an electronic switch, the neutral is pigtailed to provide a conductor to connect to the switch
Thank you for the explanation
 

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Looks like you do good work.
Pigtails: with them you have only 3 wires connected to a receptacle so even solid #12 like you are using is easy to push it into the box and screw it down. Without pigtails you would use the receptacle screws instead of wire nuts to connect everything. 6 wires makes it a lot harder to push the device in. With stranded this does not matter as much.

When you use the receptacle screws instead of wire nuts, you rely on the brass interconnect tie between the screws to make contact. These interconnect ties are not always reliable and can act like fuses. On hot side this is just an inconvenience, but on the neutral side it may be a hazard because an open neutral in a shared neutral circuit can can expose loads to high voltage.

The rockers will get there before trim out and will cause a lot less damage if you only have pig tails in front and the rest of the wire tucked in.

In the USA you need a neutral in the switch box because there are now smart devices that need line power and the neutral to run their brains. If you are using raceway the neutral can be pulled in later, but with cable you need to install it even if it won't be used.
 

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When you use the receptacle screws instead of wire nuts, you rely on the brass interconnect tie between the screws to make contact. These interconnect ties are not always reliable and can act like fuses.
Um... no. Years ago someone on here, I think Brian John, ran high current tests through receptacles and found out that they can handle far more current than you should ever even dream of running in a receptacle circuit. They were not the weakest link.

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Discussion Starter · #7 ·
Looks like you do good work.
Pigtails: with them you have only 3 wires connected to a receptacle so even solid #12 like you are using is easy to push it into the box and screw it down. Without pigtails you would use the receptacle screws instead of wire nuts to connect everything. 6 wires makes it a lot harder to push the device in. With stranded this does not matter as much.

When you use the receptacle screws instead of wire nuts, you rely on the brass interconnect tie between the screws to make contact. These interconnect ties are not always reliable and can act like fuses. On hot side this is just an inconvenience, but on the neutral side it may be a hazard because an open neutral in a shared neutral circuit can can expose loads to high voltage.

The rockers will get there before trim out and will cause a lot less damage if you only have pig tails in front and the rest of the wire tucked in.

In the USA you need a neutral in the switch box because there are now smart devices that need line power and the neutral to run their brains. If you are using raceway the neutral can be pulled in later, but with cable you need to install it even if it won't be used.
Awesome thank you for that great information!
 

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Ok so this may be a dumb question but I'm only 2 months into the trade and I'm having a hard time picturing and understanding the concept and purpose for switch legs and pigtails and when they are needed.
A switch leg is just a circuit design where you run a constant hot down to a switch, and a switched hot back. If a cable with just a black and white and ground were run to the switch leg, the white was used the white for switched hot - it's not a neutral. (The rules for this have changed but that's another question.)

So pigtailing ... it's done less in residential work. In residential work, you'll usually have a string of receptacles on a circuit daisy chained from one to the next. One romex comes in to each box to supply the receptacle in that box, and another romex cable goes out to supply the next receptacle in the string. Normally the termination is done without a pigtail: connect the two blacks / hots to the receptacle's two hot terminal screws, and the two whites to the receptacle's two neutral screws. There's a tab between the screws on the receptacles that connects them. (The tab is removable for certain wiring but normally it's not removed.) The tab is connecting the upstream to the downstream.

Pigtailing is done pretty much always in commercial work, around here at least. It may be a specification from the customer that you must use pigtails. There is a code rule for shared neutral circuits that you have to wire it in such a manner that if a device (such as a receptacle) is removed, it doesn't disconnect the neutral from anything else on that circuit. (BTW, shared neutral circuits are more common in commercial wiring.) When the downstream connection is through the tab as described above, that would not satisfy the rule. If you put a pigtail on the neutral terminal on the receptacle, and splice the neutral on the incoming supply, the neutral on the outgoing feed downstream, and the neutral pigtail, it satisfies the rule. If you remove the device, removing and capping the wires from the terminal screws, the neutral connection downstream is not affected.

I believe it would be perfectly compliant to pigtail the neutral and land the hots on the receptacle, but that's just not done - again, in commercial work, most people pigtail everything, hots, neutrals, grounds.

There are pros and cons to both methods that you can look to arguing over for the next 30 years or so :)
 

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In the USA you need a neutral in the switch box because there are now smart devices that need line power and the neutral to run their brains. If you are using raceway the neutral can be pulled in later, but with cable you need to install it even if it won't be used.
You only need the neutral if the electronic device requires it. If using non auto lighting control a Neutral Must be in the switch box. If lighting is auto controlled, either from a EMS system or a wall oc that does'nt require a neutral, you do not need a neutral in the switch box. That is why it is essential to know what is required before rough in. Art404 (C)(6)
 

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You only need the neutral if the electronic device requires it. If using non auto lighting control a Neutral Must be in the switch box. If lighting is auto controlled, either from a EMS system or a wall oc that does'nt require a neutral, you do not need a neutral in the switch box. That is why it is essential to know what is required before rough in. Art404 (C)(6)
I'm not NEC but that's not what it says.
 

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You only need the neutral if the electronic device requires it.
This is the part of your post that is in error. Even if a toggle is installed you still need a neutral unless you can pull one in later.

We have similar lingo in the CEC.
 

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We pigtail every outlet and switches(if needed) it's good practice no matter if it's residential or commercial.

As far as pig tailing for switches boxes....most commercial wall switch are wall occupancy sensors(WOS)....now some brands of WOS devices have screw terminals on the device and some have wires. If the WOS have wires you don't need to pigtail simply connect wires to Hot, ground, load and neutral.....if they have screws terminals you need pigtails for Hot, ground and neutral.
 
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