Electrical Outlet wire connections (C) D FriedmanElectrical Receptacle Wire Connections
How to wire up an electrical plug outlet or wall receptacle / plug
     


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How to wire up an electrical receptacle:

Here we illustrate basic connections seen in the field for the black, white neutral or grounded conductor), and ground wire when hooking up an electrical receptacle (wall plug or "outlet").

We describe how to wire an electrical receptacle by making the right connections between individual electrical wires and the proper screw or clamp connectors on the electrical receptacle device itself.

We also describe connecting the ground wire between the circuit grounding conductor, receptacle ground screw, and the electrical box (if metal boxes are used).

Watch out: mis-wired electrical receptacles are dangerous. Electrical wiring should be performed by a licensed, trained electrician and should comply with the National Electrical Code and local regulations. This article series describes how to choose, locate, and wire an electrical receptacle in a home.

Green links show where you are. © Copyright 2015 InspectApedia.com, All Rights Reserved.

Electrical Wiring Connections for Installing an Electrical Receptacle

Color coding of wires to properly connect an electrical outlet (C) Carson Dunlop Associates

The illustration at left shows the typical wiring of an electrical outlet or "receptacle", courtesy of Carson Dunlop Associates.

Watch out: Electrical components in a building can easily cause an electrical shock, burn, or even death. Even when a hot line switch is off, one terminal on the switch is still connected to the power source.

Before doing any work on the switch, the power source must be turned off by setting a circuit breaker to OFF or removing a fuse.

Click any image to see an enlarged, detailed view of electrical wiring details for "plugs" or electrical receptacles. Our photo at page top is not an example of a proper electrical outlet installation.

If you are wiring a 2-wire electrical circuit that has no ground wire, also see CONNECTION for 2-WIRE RECEPTACLE CIRCUITS for proper wiring details.

Where do the Black, White, & Bare Ground Wires Go on an Electrical "Outlet" or Receptacle?

Electrical Outlet wire connections (C) D Friedman

So where do the wires go: to which screws on the electrical receptacle (shown just above) do we connect the black wire, white wire, and ground wire? And what if there is no ground wire?

On a conventional 120-volt "two pronged" electrical outlet that accepts grounded plugs (two prongs plus the rounded center ground connector prong), your circuit will have three wires:

  • The white "neutral" wire - this wire is connected to the silver screw on the electrical receptacle, often labeled "neutral" or "white". You can see our white neutral wire connected to a silver screw on the receptacle in our photo.
Electrical Outlet wire connections (C) D Friedman
  • The black "hot" wire - this wire is fed from the circuit breaker to deliver power to the receptacle, and it connects to the brass or bronze-colored screw on the receptacle, often labeled "hot" or "live" or "black" (or "red" in some situations).

You will see the hot black wire connected to the bronze or darker-colored screw on the receptacle shown at below right.

The receptacle we used for these photos happens to be a 20-A rated device that permits the wire to be inserted straight into a clamp that is tightened against the wire by the screw.

Also see BACKWIRED ELECTRICAL RECEPTACLES.

Electrical Outlet wire connections (C) D Friedman
  • The bare ground wire - this wire connects to the green ground screw usually found on the bottom of the electrical receptacle (photo at left). You can also see our ground wire connected at the left side of our previous photo, above-left.

 

What's the difference between "line" and "load" terminal screws on electrical receptacles?

GFCI wiring details, back view (C) Daniel FriedmanWhat is the difference between the load and line terminal screws on a 15 or a 20 amp receptacle? How do i wire 4 more recepticles to an existing receptacle in a room? - Anon

 

Reply: how to wire line and load terminals on receptacles (outlets)

Anon: the line and load electrical wire connections are important to get right on certain electrical devices such as GFCIs and AFCIs. Our photograph (left) illustrates the line and load markings on the back of a GFCI electrical receptacle.

 

Looking at the side or back of the molded case of this and other electrical devices such as AFCIs, you will see that one pair of terminals will be marked "line" and the other "load".

 

 

Which wires connect to the "Line" terminals:

The Line terminals (green arrows in photo at left) on an electrical receptacle are for the incoming hot wire - the terminal marked LINE is connected to the incoming power source or the "hot" wire (typically black or red in insulation color) that connects to the brass colored screw (marked "Black" or "Noir) at the lower left " in our photo.

And the incoming neutral (white) wire from the electrical panel connects to the "Line" and "White" or "Blanc" terminal marked at the lower right in our photo

Which wires connect to the "Load" terminals"

The Load terminals (red arrows near the top of our photo at left) on an electrical receptacle are for the outgoing wires. These wires feed electrical receptacles that are located "downstream"(farther from the electrical panel) from the device. The outgoing hot or black wire (red arrow, above left in our photo) connects to the terminal marked "Load" or "Charge" and "Black" or "Noir". The outgoing white, neutral wire, connects to the terminal marked "Load" or "Charge" and "White" or "Blanc" in our photograph.

Re-stating, terminals marked LOAD on a GFCI or AFCI are intended to be used to feed other devices (such as receptacle) that are wired "downstream" from the one being worked-on. In a string of electrical receptacles wired in series, incoming electrical power flows in to the first GFCI/AFCI receptacle and is connected to the LINE terminal. The LOAD terminals of that device are connected to hot and neutral wires that subsequently are connected to the next electrical receptacle in the series.

To hook up a quad of electrical receptacles you'll need a larger junction box. And often we wire two separate electrical circuits to the box, placing one pair of receptacles on one circuit and the other on the second circuit - that approach allows us to plug more devices into the wall at that location with less chance of overloading a single electrical circuit in the building.

Watch out: while a conventional receptacle may work with the line and load terminals reversed, a GFCI or AFCI will be unsafe if wired with that mistake, and those devices will not work properly nor test properly in all circumstances. For example, if you connect the incoming "hot" wire and neutral wire to the "load" terminals on a GFCI, and if you connect wires leading to downstream electrical receptacles to the "line" terminals (these are the incorrect connections), then pushing the test button on the GFCI will not activate that device's internal trip mechanism.

How to Extend Too-Short Wires in the Junction Box when Wiring a Receptacle

Reader Question: can I connect a pigtail from multiple hot, neutral, or ground wires over to a receptacle

I have 2 receptacles that are both side and back wired, 3 hot and 3 neutral wires. I eliminated one receptacle (capping the 3 wires together) but want to keep the other. Is it safe to just run a pigtail from the 3 wires to the receptacle? - Greg

When wiring multiple boxes in series, how do you connect both incoming and outgoing ground wires to the back of the receptacle? With 12 ga. wire, only one wire will fit under the green screw (and not very tightly, at that - there's no washer or clamp.) - Bob M.

Reply:

Yes, Greg, that's a common practice. Be sure that your junction box is big enough to contain all of the wires and twist-on connectors.

Bob, similar to Greg's question, I see two approaches to hooking up the ground wire in junction boxes and at electrical receptacles.

  1. If the incoming ground wire from the feed circuit was left long enough, it can be run continuously, connected to a grounding screw that connects the wire to the metal junction box (skip this step if plastic junction boxes are in use), on to the ground screw terminal at each electrical receptacle, and ending with a ground clamp crimp connector that ties the incoming ground to the ground wire of the outgoing wire that continues to the next junction box.
  2. If the incoming ground wire is not long enough to run as above, then an additional length of ground wire is pigtailed to the incoming ground and makes the other connections I've described above. S

    ee ELECTRICAL SPLICES, HOW TO MAKE.

Details about back-wired electrical devices (receptacles & switches) are
at BACK-WIRED ELECTRICAL DEVICES.

Electrical receptacle mounting strap and screw are not a ground (C) D FriedmanIn sum, all of the grounds are tied together in the box: the incoming ground, outgoing ground, and ground wires to each of the electrical receptacles.

Watch out: while the electrical receptacle ground may also be electrically connected to the metal strap that mounts the receptacle to the junction box (photo at left), and while the junction box may be metal, do not rely on the receptacle mounting screws and receptacle strap-to-box contact to serve as the grounding connection.

It's easy for the receptacle mounting screws to be deliberately left loose or to work loose - making that ground connection unreliable. Use a ground wire, as the connection through the receptacle mount screws is simply not reliable.

 

Reader Question: I don't have enough wire to lower receptacles on the wall

I recently moved into a 3 1/4 story home, and I have a basement that I am trying to finish with drywall. The room is down to the studs and the electrical receptacles are about 4' up the wall.

The Romex wiring is stapled, and there isn't enough wire to lower them. It is way to much work for me to replace all of the downstairs wiring right to the breaker box, so I'm wondering if it is possible to add onto the existing wires and attach wire screws or marrets within the walls before I start adding drywall, or whether I should add some kind of junction box to contain the marreted wires in between.

My building code stipulations would differ in some cases because I live in Canada, but I just want to do the job right, and I do not want to take the chance of having any fire hazards, as I also have small children. - Dave 2/10/12

Reply: if you have to move an entire string of electrical receptacles complete re-wiring is faster and cheaper than adding a splice box for every device.

Dave,. you are correct to be careful about moving outlets or any other device when the existing wires are too short. The temptation is to just splice on an extension and bury that in the wall or ceiling: an illegal, improper, unsafe as well as really aggravating approach.

The proper approach is to add a junction box at each splice - we never splice 120/240V wires without including them in a box. You can reduce the wiring work a little by using plastic boxes instead of steel - avoiding having to also connect the box to the ground wire.

See ELECTRICAL SPLICES, HOW TO MAKE.

The proper approach also means that you don't then bury any of these splice-boxes in the walls either. Each box has to be brought to the surface and covered.

The result is a lot of work and expense and an ugly wall with an extra junction box and blind cover all along the wall over each of the now moved or lowered electrical receptacles.

Frankly I figure that especially as you've already got the wall open to the studs, if there are more than one or two receptacles to be moved you'll probably find it is actually much less total work to re-wire the entire circuit, allowing proper lengths of wires for each box. You might carefully remove and re-route the existing wire lower in the wall or you might buy all new electrical wire - depending on the age and condition of the existing materials.

Watch out: when removing wire that appears to be in good condition, if you nick the insulation you've created a new hazard.

Connecting the Ground Wires at the Receptacle & at the Electrical Box

Electrical Outlet wire connections (C) D Friedman

Proper grounding connections for an electrical receptacle

The electrical receptacle must be properly connected to the building grounding system - not shown in our sketch.

That connection is made from the ground screw on the receptacle to the grounding conductor (usually bare copper) in the wire leading back to the electrical panel where in that location it is connected to a grounding bus and from that bus to the building grounding system, one or more earth-driven electrodes or their equivalent.

The incoming ground wire is connected to the ground terminal on the electrical receptacle (usually a green screw such as shown in our photo at left).

Details of ground wire connections for electrical receptacles are given at GROUND WIRE CONNECTIONS.

How Many Conductors Should be in the Receptacle Circuit? 2-Wire? 3-Wire? 2-Wire with Ground?

Two wire14/2 and 12/2 Wires for 15-A or 20-A circuits

14_2_NMB_electrical wire (C) D Friedman

The electrical wire must have the proper number of conductors. In modern electrical circuits used to wire receptacles (electrical outlets).

Typically an electrical receptacle is wired with two insulated wires and a bare ground wire, all three of which are encased in a plastic (NMC) or metal (BX) jacket.

You'll see this wire labeled as 14/2 Type NM B with ground (photo at left) or 14/2 Type NM C with ground.

These wires are color coded black, white, and bare (photo below right). Sketch at left showing the number of conductors in types of electrical wire is provided by of Carson Dunlop Associates.

Watch out: If your electrical circuit has only black and white wires, that is, no grounding conductor, then you are wiring a 2-wire electrical circuit that has no ground:
see CONNECTION for 2-WIRE RECEPTACLE CIRCUITS for proper wiring details.


Skecth of number of conductors in types of electrical circuits (C) Carson Dunlop Associates Electrical wire 14-2 with ground (C) D Friedman

14/3 and 12/3 Three-wire Shared Neutral Electrical Circuits for Receptacles

Some electricians run a three-wire, shared neutral circuit ( to permit two independent receptacle circuits in an area while pulling one less wire through the building. You'll see the labeling on such wires as 14/3 or 12/3.

A 14/3 or 12/3 wire will actually provide four physical wires: one neutral wire, two hot wires (black and red), and a ground wire. A common use of shared neutral circuits is the wiring of quad-receptacle hookups or duplex receptacle hookups in a kitchen where we want two separate 20-A circuits and thus might use 12/3 wire.

Watch out: AFCI and GFCI devices may not work properly when the neutral wire is shared. Since the kitchen circuit must be GFCI or AFCI protected, we can no longer recommend using shared neutral circuits in this location even if it is permitted.

Watch out: for a shared neutral circuit to function safely in the electrical panel the two hot wires are connected to a double pole common internal trip circuit breaker.

Details about how shared-neutral multiwire branch circuits are wired can be found
at MULTI-WIRE CIRCUITS

Reader Question: When wiring an electrical receptacle, what do I do with the red wire? Can I ground it?

I have a 3 wire (Black, White, Red and ground) feeding a outlet and I want to add another receptacle to run further down the line. The line out is 14/2. What do I do with the Hot Red wire? Can i attach it to the ground. - Rick

Reply: NO!!

Rick:

NEVER connect a hot (red or black) wire to ground (nor to the white neutral wire) - doing so would form a dead short, should trip a breaker, or if not, could cause a fire or could cause a dangerous shock.

If there is a hot wire that is not used in a junction box, SOP would be to cap it off with a twist-on connector.

It sounds as if you'd be best served by hiring a licensed electrician.

Reader follow-up:

After capping off the red wire, can I extend the line to the next plug by following the diagram above and adding the black and white wires to the respective second screw connections?

You see, the wiring has already been installed by the builders and they left the boxes without receptacles so all I have to do is connect them to the. I don't know why the extra red wire is there. It was done over a year ago. I want to finish the connections. It runs 14/3 and then 14/2. That's why I have the extra red.

Reply: how three-wire circuits or multiwire branch circuits with a common neutral (and ground) are used and wired

Rick often electricians run a 3-wire system into a building area using two hot wires and a shared neutral, to permit providing two circuits in an area while having to pull just one wire to the area. But to sort out how your wires were connected and are being used requires some expertise, visual inspection, and testing using a VOM.

Take a look at multi-wire branch circuit wiring information and hook-up details at MULTI-WIRE CIRCUITS.

Reader Question: how to wire up a pair of receptacles in one electrical box

Quad plex electrical receptacle wiring (C) Daniel FriedmanI would like to wire 2 single plug ins to one live wire..how do i do that? - Channing

Reply:

Channing, re Hooking up a Pair of Receptacles in One Electrical Box:

If your two plug ins (two electrical receptacles) are located in the same electrical box (we call this a "quad" electrical receptacle installation since each individual receptacle provides connections for two wall plugs), you'll want to wire the hot and neutral to one pair of screws on the first receptacle, and use short black and white jumper wires to connect the the proper terminals on the first receptacle to the second one in the same box.

That's a perfectly acceptable use of the second pair of screw terminals you see on the receptacles.

The ground wire can be continuous, tying the two ground screws on the receptacles together and onwards to the circuit ground.

However a better practice when wiring up a quad-plex of electrical receptacles is to place left and right or upper and lower receptacles on separate electrical circuits - thus reducing the chances of overloading the circuit when many things are connected simultaneously. There are two approaches: you can wire the left and right duplex receptacles each to different individual electrical circuits, or you can wire the upper and lower half of the pair of duplex receptacles to different electrical circuits.

Wiring a Split Receptacle to Two Different Electrical Circuits

Electrical receptacle split receptacle wiring (C) Daniel FriedmanIf you choose to wire the upper and lower duplex receptacle openings to different circuits, we call this the "split receptacle" wiring method, because we are splitting the individual duplex receptacle upper and lower connectors onto two different circuits.

Our photo (left) shows an electrical receptacle that is being wired to a single circuit. The white neutral wire is connected to the silver screw (left side of our photo).

If we were wiring this electrical "outlet" as a split receptacle, we'd want to feed the upper and lower halves of the device from two different electrical circuits.

To do so we'd have to break away the "breakaway" connecting tab pointed to by our orange arrow.

Daisy Chaining Receptacles in Separate Electrical Boxes

If your two receptacles are in different locations and thus in different electrical boxes, your circuit that wires the second or "downstream" receptacle can be powered by those same extra terminal screws on the first or "upstream" receptacle. You'll need to run a wire from the first receptacle through the wall into the second electrical box of course.

Wiring Electrical Receptacles on a Single Circuit In Parallel

In some jurisdictions electricians to not "daisy chain" receptacles in the same box together by using the second pair of screws on each one. Rather the circuit enters the box and using twist-on connectors, short pig-tail wires are connected to each receptacle at the proper screws. This approach requires a larger electrical box as it will contain more connections, connectors, and so needs more room.

Question: what is the minimum height that indoor house wiring must be above the ground or floor level?

When running wire for a basement, is there a min height the wires must be off the ground? Not the outlet box, but the wire running through the joists. Justin Sheppard

Reply:

No, Justin. But if there is the slightest danger that wires will be nicked by someone driving a nail into a stud though which the wires are run be sure to use steel plates to protect the wire where it passes through the studs. Simple nail plates are available at any building supplier.

Question: are electrical junction boxes required for wall plugs?

Burned up electrical receptacle (C) Daniel FriedmanDo I really need an electrical box to put a new wall plug in ? - Thomas

Reply:

Yes, Thomas, electrical devices such as switches and receptacles (wall plugs) need to be mounted in a code-approved plastic or metal receptacle (box) for fire safety as well as to assure that the device is mechanically secure. In fact when you purchase a "wall plug" you'll see that its metal mounting ears and screws are spaced and designed to connect to an electrical box.

Watch out: while it's physically possible to install a wall receptacle or "plug" without using an enclosure, doing so is dangerous, risking fire and shock, and of course, it's also illegal in virtually every building code jurisdiction.

Take a look at our photograph at left - a fire was contained within this electrical junction box. Had the box been omitted there is a good chance the fire would have spread to the building itself.

When we hear a question like this it makes me very afraid for you and for future building occupants - as amateur electrical wiring is dangerous.

Question: When wiring an electrical receptacle, what do I do with the r

Question: how do I install multiple electrical outlets (receptacles) along a wall?

putting in more than outlet on along a 12ft wall - Mike Tucker

Reply:

Mike, if your comment is a question of how to put in more than one outlet along a 12 foot wall, yes it's perfectly permitted to exceed the minimum number of receptacles along a wall.

The wiring system is unchanged except that in some cases I recommend installing two different circuits and alternating which outlet is served by which circuit. That avoids overloading one circuit if you are plugging in lots of devices in one area.

Reader Question: Is 14/3 wire ok to use to wire between the light switch and the light? What about an electrical outlet on the same circuit as the ceiling light fixture?

is it okay to use 14/3 wire for power to light to switch to receptacle?

Reply:

Anon:

If you are asking about using a shared neutral wire on a lighting circuit combined with an electrical receptacle circuit, see (search InspectAPedia.com for) our article on "multi wire branch circuits" or "shared neutral electrical wiring".

In general we'd use 14-2 wire on a 15 amp circuit to power electrical receptacles and a SEPARATE circuit to power the lighting fixtures. If we lose power on one circuit we want the other still working so that there is safe lighting in the area.

For a light fixture such as a ceiling light, in addition to bringing power to the junction box where the light fixture is to be mounted (using 14-2 copper wire) we'd use a separate length of 14-2 wire to run from the light switch to the junction box to control the light. Tape the white wire at both ends of the switch circuit with black tape so that the next worker knows that this is a switch circuit and that the white wire is not a neutral wire.

Watch out: we do not wire fixed lighting fixtures such as ceiling lights on the same circuit as electrical receptacles ("wall plugs"). If one of the two circuits should be switched off by a circuit breaker (perhaps detecting a fault or overcurrent) we want the other circuit to remain on so that room occupants are less likely to be left in darkness.

Question: can I connect a pigtail from multiple hot, neutral, or ground wires over to a receptacle

I have 2 receptacles that are both side and back wired, 3 hot and 3 neutral wires. I eliminated one receptacle (capping the 3 wires together) but want to keep the other. Is it safe to just run a pigtail from the 3 wires to the receptacle? - Greg

When wiring multiple boxes in series, how do you connect both incoming and outgoing ground wires to the back of the receptacle? With 12 ga. wire, only one wire will fit under the green screw (and not very tightly, at that - there's no washer or clamp.) - Bob M.

Reply:

Yes, Greg, that's a common practice. Be sure that your junction box is big enough to contain all of the wires and twist-on connectors. Details about back-wired electrical devices (receptacles & switches) are
at BACK-WIRED ELECTRICAL DEVICES.

Bob, similar to Greg's question, I see two approaches to hooking up the ground wire in junction boxes and at electrical receptacles.

  1. If the incoming ground wire from the feed circuit was left long enough, it can be run continuously, connected to a grounding screw that connects the wire to the metal junction box (skip this step if plastic junction boxes are in use), on to the ground screw terminal at each electrical receptacle, and ending with a ground clamp crimp connector that ties the incoming ground to the ground wire of the outgoing wire that continues to the next junction box.
  2. If the incoming ground wire is not long enough to run as above, then an additional length of ground wire is pigtailed to the incoming ground and makes the other connections I've described above.

Electrical receptacle mounting strap and screw are not a ground (C) D FriedmanIn sum, all of the grounds are tied together in the box: the incoming ground, outgoing ground, and ground wires to each of the electrical receptacles.

Watch out: while the electrical receptacle ground may also be electrically connected to the metal strap that mounts the receptacle to the junction box (photo at left), and while the junction box may be metal, do not rely on the receptacle mounting screws and receptacle strap-to-box contact to serve as the grounding connection.

It's easy for the receptacle mounting screws to be deliberately left loose or to work loose - making that ground connection unreliable. Use a ground wire.

Question: connecting 14-3 to 14-2 wires & to the junction box

How do you connect 14-3 to 14-2 to a junction box - Moe.

Reply:

Moe, twist on connectors are used to connect the incoming and outgoing hot, neutral, and ground wires, and a single pigtail length in that same twist-on connector can connect the ground to the local junction box.

Watch out: when mixing 14-3 and 14-2 wires on an electrical circuit.

If the 14-3 wires are the hot wires entering the box, and if only 14-2 is leaving the junction box, cap off the unused (typically the red) hot lead.

Do not just bond it together with the outgoing hot wire in the 14-2 group. Making that mistake would short two hot leads together, would be improper, unsafe, and a fire or shock risk.

Reader Question: electrical outlet height requirements

I was looking at some height requirements on electrical outlets this is a very informational site.

thanks Jerm 4/19/12

Reply:

Jerm, in the article above at HEIGHT above FLOOR for OUTLETS we give the data you want. Let me know if anything is unclear.

Question: how do I wire a switched electrical receptacle?

I have double receptacle that has 3 wires coming in: one being the main power wire; one is incoming which feeds another receptacle, and the 3rd wire will feed a single pole switch. How do I wire the receptacle and then, how do I wire the single pole switch with 2 incoming wires? - JMS 6/3/12

Reply:

JMS I don't have a perfectly clear idea of what you are wiring, but it may help to simplify: using a twist on connector and additional short wire lengths, the incoming hot and neutral can then be connected to receptacles in the same box, and any outgoing hot and neutral join the same twist on connectors.

Typically when I see a switch wired from a receptacle box the switch is being used to make one of the receptacles switchable while leaving the others always -on. in that case the electrician may run a 14-2 wire (hot, neutral, ground) from the receptacle box to the switch, putting black tape on the ends of the white wire to show that BOTH wires are actually carrying current. Those wires, back in the receptacle box, then interrupt power to the "switched" receptacle.

Reader Question: can I add an electrical outlet on the wall where there is already a light switch?

I would like to wire in an outlet on the same wall where there is currently a light switch. Can I run wires from the light switch to power the outlet?The light switch is a 2 way switch. thank you. - Marv Walker 7/10/12

Reply:

Marv.

Well yes, maybe, sort-of.

Because a light switch is indeed switching a hot wire to the light, you've got power at the switch location. But depending on how the building is wired, you may not have an acceptable neutral wire, and in some still older circuits you may not have a safe ground wire.

Provided that you know how to work on electrical wiring without getting killed by electrocution, you (or your electrician) will open the switch box, carefully pull the switch assembly out enough to inspect for additional wires that may be present, and then use a VOM or DMM or even a simple neon tester to determine what wires are present.

To add a receptacle you need a proper hot, neutral and ground wire.

Watch out: if the "hot" wire in your light switch is on a 3-way circuit you may not always have power at your add-on receptacle.

Reader Question: armor around wire through concrete?

I am running a new 15A outlet into the back of a bookcase in a 50 year old house with updated electrical. The wire runs out the back of the retrofit box and down through the concrete foundation into the crawlspace to a wire I plan to splice into. Do I need to put armor around the wire run through the foundation? It goes through open air for about 2 feet and there is no way to secure it to anything.

Thanks!
Tom - 7/19/12

Reply:

You need to look at the type and rating of the electrical wire to determine if it is permitted to bury it in concrete or not.

Question: are receptacles wired "downstream", that is, after a GFCI receptacle OK?

Are receptacles wired after GFI receptacles OK? - Denny 11/25/12

Reply:

Denney,

Yes, and if wired correctly the downstream receptacles will also be GFCI protected.

Watch out: When wiring a GFCI the incoming leads are connected to the LINE terminals and the downstream receptacles are connected to the LOAD terminals marked on the back of the receptacle. If the devices is not wired correctly it is unsafe and does not provide the intended safety protection from ground faults.

Reader Question: how do I wire multi-way light switches so that all switches can be "down" or "up" when the lights are all off.

How should multiple way light switches be wired so that when all switches are down/up the light is off? Only some of the two-way switches in the house are working that way. With the 3-way and 4-way there's always one switch that has to be opposite the others.
Thx, Jim

Reply:

Jim this is one of my favorite questions - thanks. Because a circuit with two or more "three-way" switches installed can be turned on or off from any of the switches on the circuit, it is impossible to wire the circuit so that when the circuit is "OFF" all of the switches are in a predictable position, say "down" (which we like to use to mean "off").

Imagine that all the switches are "down" and the lights are off (which is a possible case). Someone turns the lights ON at switch #1.

When someone wants to turn that light OFF, IF and ONLY IF that very same switch (now in the "up" position) is used, then by definition they are going to be using some other switch (now in the "down" position). When that "other" switch is used to turn lights off, it was "down" and is now switched "up".

You can't get there from here on a conventional 120V 3 or 4 or n-way lighting circuit.

Reader Question:

I have one line with power coming into a box that will have one two way switch, one three way switch and one power line exiting. Is it proper to splice the incoming black wire to make 3 black wires by pig tailing with wire connectors and doing the same for the white wire and ground? - is it ok? 12/13/12

Reply:

I'm sorry but I'm confused by the question. I think it's safe to say that in general it's common practice to use a twist-on connector to splice pigtails or individual wires at an individual hot or neutral wire where more connections are needed than fit with the original wire.

Just watch out to avoid violating the space or number of connectors permitted in a junction box of the particular size you're working on.

Question: which circuit is better to use when adding a closet light

If I want to add light to closet, which circuit is it better to pull from? I have access to 120 plug and switches in outside wall facing away from closet that could be pulled into closet. Also, can you help explain the two different wiring configurations on my non GFI plugs.

On two different plugs on different walls the plugs are 8 wire push in style (4 hot and 4 common), but the wiring config is different between the two plugs. One one all white and black are inserted in the bottom 4 connectors with tabs in place. On another same style plug, one set of 4 wires (2 blk and 2 white) are inserted in bottom left row, and other set of 4 wires are inserted in opposite side top row. These plugs are not controlled by switches. Thank you. - Chris 12/30/12

Reply:

Chris,

In my OPINION, it's best to connect a closet light to the room lighting circuit if possible.

About your other question, I'm a little confused by the query, but in general, receptacles and switches often have more than one permitted connection point, such as under a screw terminal, on older devices via a back-wiring push-in connector (something we do not recommend using), or on newer devices a side-clamp operated by a screw.

In all events, regardless of which connection point you are using, receptacles and switches have a designated side or screw or connector set for the white (neutral wire) (typically the side that has a silver colored screw and that is marked NEUTRAL on the device) and for the black (hot wire) (typically the side that has a brass-colored screw and is marked LINE or HOT or BLACKI).

 

 

Continue reading at GROUND WIRE CONNECTIONS or select a topic from the More Reading links shown below.

or see CONNECTION for 2-WIRE RECEPTACLE CIRCUITS - no ground

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