Electrical Panel Projects

Installing A Circuit Breaker

Do-It-Yourself Repairs and Basic Wiring Projects:
Replacing a Breaker in Your Panel

By Terry Peterman, the Internet Electrician

Circuit Breakers

A breaker is designed to protect your wires from carrying too much current, and to trip off on an overload or a short circuit.  That is why proper sizing of breakers is so important (i.e. #14AWG wire on a 15 Amp breaker, #12AWG on a 20 Amp breaker, etc.).  This is all spelled out in the CEC and NEC.  Never oversize a breaker to solve a tripping breaker problem!

The first question to ask yourself is Why am I replacing this breaker?

If you are adding a circuit, and now need to install the breaker, then this of course is necessary.  The situation that I run into a lot is people wanting to replace a breaker because they think that it is faulty, or has failed, or trips off too often.  Not that breakers don't sometimes fail, but more often than not, the breaker is just doing what it's supposed to do, and the problem causing the breaker to trip needs to be rectified first.   

To Test for a Faulty Breaker

Unplug any devices that are on this affected circuit, shut off all lights, and then see if the breaker will reset.  If it resets with all known loads disconnected, then you can start re-connecting devices one by one, and/or turn on lights to determine where the problem is.

Turn off the breaker before plugging the item back in, and then reset, because if you have a short circuit in a device you can get a high inrush of current that can arc severely, possibly burning you or worse.  When a short circuit has occurred, an extremely high amount of current can flow before the breaker trips.  

Use a Voltage Tester!

If the breaker won't reset, and doesn't put out voltage on the load terminal (use a reliable voltage tester or a volt meter to check), even when all known loads are disconnected, then you probably have a faulty breaker, and it needs to be replaced. 

You will need to get all the information that you can (brand name, part numbers, breaker size, breaker type, etc.) so that you can get the proper replacement from your supplier of choice.  

Panels

Most homes will have a combination panel, with a main breaker, and then all the branch circuit breakers below.

Figure 1:  Combination Panel

Take note that even after taking off the panel cover, you don't have access to the main breaker compartment without removing the main compartment cover as well.  Don't open this cover.  If you have a problem with the main breaker, you will need to call in a qualified electrician for this. 

Figure 2:  Panel Cover Removed

Older Homes In older homes you may have a fused disconnect switch to disconnect power from the distribution panel that will isolate the breaker box to allow safe replacement of the branch circuit breakers.

In any case, arrange for some back up lighting beforehand, either with a reliable battery operated flashlight or lantern, or a portable generator with a trouble light, or lamp, etc.

In our example, let's assume that you have an ordinary combination panel, with a 100 Amp 2-pole main breaker, and then a branch circuit compartment.  We'll use a Cutler Hammer, CPM 120 Panel.  

Step One

Before shutting off the main breaker, shut off all branch circuit breakers first.

It is always best to remove the load from a breaker before shutting it off.  With the main breaker off, the buss bars that the branch circuit breakers connect to are isolated from the incoming voltage and will be safe to work on.  

Never just assume that the breaker has shut off properly - check for voltage on any adjacent two breakers to assure that the panel is dead.  

Figure 3:  Testing Power to Panel

Most homes will have 'push in' or 'stab in' type of breakers.  In some cases, usually in commercial applications, the breakers bolt into place on the buss bars.

 

Figure 4:  Square D Bolt-In Style Breakers

Figure 5:  Federal Pioneer Stab-In Style Breakers

Figure 6:  Cutler Hammer Stab-In Style Breakers

Step Two

Start by disconnecting the wire from the load terminal of the breaker and pull the wire out of the way to facilitate removal of the breaker.  

Step Three

Carefully pry the defective breaker out of its position as shown here.

Figures 7 and 8:  Carefully Pry Out Breaker

Take note as to how the breaker locks into position in the panel.  In the case of Cutler Hammer (formerly Westinghouse, Nova Line, etc.) the back of the breaker pushes back into a mounting strip first, and then pushes onto the buss bar.  

Re-insert the new breaker and push firmly into position.  Then re-attach the wire to the load terminal.  

Figure 9:  Re-Insert New Breaker

Figure 10:  Push Breaker Firmly Into Place

Figure 11:  Re-Connect Wires to New Breaker

Figure 12:  Check Breaker Connections

While you have the branch circuit compartment open, inspect for any other potential problems, like loose terminals, and it is a good idea to re-tighten all connections while you're in there.

Step Four

Now you put the panel cover back on, and if you have installed a breaker for a new circuit in a new position, you will have to remove the appropriate breaker knock-out from the panel cover.

Figure 13:  Turn On Main Breaker

After the cover is back on, it's a good idea to shut off all of the branch circuit breakers, then turn on the main breaker, and then one-by-one turn on all of the individual breakers.  Then check and test everything to see that all systems are normal.

Figure 14:  Turn On Individual Breakers

Figure 15:  Replace Panel Cover


 

Click Here For Download of The Fedders A6Y18F7A-A Manual (892K PDF).

New circuit breaker.

In This Article:

The power is turned off. A cable clamp is installed and new cable brought into the panel. The ground wire is connected to the ground bus bar, the neutral wire is connected to the neutral bar, and the hot wire is connected to the new breaker, which is then pushed into its slot.

Related Articles:

Skill Level: 2-3 (Basic to Moderate)

Time Taken: 30 Minutes

By Bruce W. Maki,

Start:
First: Turn Off The Power.

Installing a basic single-pole circuit breaker involves 4 steps:

  1. Feed the cable into the breaker panel.

  2. Connect the ground wire.

  3. Connect the neutral wire.

  4. Connect the hot wire to the breaker and snap it in place.

Step 1:

In this case, the power was controlled by a 100 amp breaker on the main breaker panel.

I turned off the breaker.

Then I removed the cover from the breaker panel.

This situation is a little different from most houses. This house has a 200 amp main breaker panel, which feeds 3 subsidiary breaker panels. This is a good technique for house wiring, although it does cost a little more.

This method allowed me to shut off the power at the main panel, so the 100 amp sub-panel had no live wires anywhere.  But there was still power to some parts of the house.

Most houses have just one panel, which contains the main breaker (typically 100 to 200 amps) and a large collection of single pole (120 volt) and double-pole (240 volt) breakers. In these cases, installing a breaker can be done safely, BUT...

There are still live wires present.  The big wires that enter the panel and feed the main breaker.  Avoiding contact with these wires is very important. (Worse would be accidentally shorting the service entrance wires with a metal tool, because they have a huge current capacity, and short-circuiting these wires would create a massive arc, like a big industrial welder, which would continue until something in the circuit was melted.  I know of no circuit breaker (other than the main breaker) that protects your service entrance wires from shorting.  I have seen 240 volt service entrance wires short together (during a windstorm) and the sparks are spectacular. I was surprised to learn that most step-down transformers that supply houses do not have short-circuit protection.

Inside details of circuit breaker panel.

Breaker Panel Anatomy:

1, 2. Incoming Hot wires. There is 240 volts between these wires, or 120 volts between either wire and the neutral line.

3. Neutral wire. This is at the same electrical potential as the ground. At the main breaker only, the neutral is connected to ground.

4. Ground Bus Bar. This strip of metal has a row of screws for connecting the ground wires of the various circuits.

5, 6, 7. Neutral Bus Bars. This panel has 3 short bus bars for neutral wire connections. Some panels have only one long bar.

8. Circuit Breakers. Each single-pole breaker connects to one of the two hot bus bars. Each double-pole breaker connects to both of the bus bars (thus providing 240 volts between hot wires).

9. The last available space in this panel. Our new breaker will go here. 

Note in the above photo that there is no main circuit breaker. This is a main lug type of panel, used as a subsidiary panel (sub-panel).  The breaker that feeds this panel is upstream, at the main panel. 

I touched the probes of my electrical tester to the incoming hot wires...

...No voltage, just as planned.

 

This is the volt-meter reading with the power turned on. That could really hurt.

 

After I installed a 3/8" cable clamp, I ran the cable into the panel.

See Installing A Cable Clamp for more info.

I tightened the clamp with a cordless drill-driver on a low torque setting.

 

I used a sharp knife to CAREFULLY slit the cable jacket.

And then I cut away the jacket, all the way back to the cable clamp.

 

Step 2: Connect The Ground Wire

A closer view of the ground bus bar. 

The new ground wire was snaked through the maze of wires. I made some bends so the wire would lay in an orderly fashion.

 

I loosened a screw and inserted the ground wire...

...and I tightened the screw firmly.

Notes On Screw Tightness:

Most circuit breaker panels have instructions that dictate the proper amount of torque (twisting force) to apply to the screw when tightening.  This panel specified 20 inch-pounds for #12 and #14 wire.  I have never seen an electrician use any type of torque measuring device when installing electrical equipment.  But be warned, there is a correct amount of tightening, and it's quite firm. Certain things can happen when the conductors are under full current load, such as heating, thermal expansion and distortion of the round copper wire. If a screw is not tight enough, a wire may begin it's career being secure but eventually become loose after repeated heating/cooling cycles.

Of course, if a screw is tightened too much, the threads will strip or the drive slot will strip. Anybody with doubts about tightness should purchase a good quality torque wrench and screwdriver attachments and become familiar with just how tight 20 inch-pounds feels like.

 

Step 3: Connecting The Neutral Wire

The neutral line feeding the panel is supposed to be marked white (this one was covered with white electrical tape, which is OK).

I routed the wire neatly and made some bends.

 

I stripped the insulation from the end of the wire and inserted the bare end into a connection terminal.

The screw was tightened.

 

Step 4: The Hot Wire

There was one empty spot in this panel.

A Square-D brand of single-pole breaker, 15 amps.

 

A view of the connection terminal on the breaker. Two wires can be attached.

A view of the bottom. The metal U-clips on the right hold the unit to a plastic bar in the panel. The U-clips on the left (hard to see in this shot) are part of the circuit, and connect to the hot bus bar.

 

The hot wire was stripped and secured under the screw.

Note the metal bus bar. The circuit breaker grabs on here.

 

The installation sequence. First the hold-on clip is pushed onto the plastic bar. (I angled the breaker so a photo could be taken. In practice the breaker is parallel to its neighbor.)

With my thumb I pushed firmly until the breaker was seated. The left end was still not connected.

 

The business end was pushed in firmly until it was seated.

There are no screws that attach this type of breaker to the panel, it is held in only by spring clips.

 

Wrapping Up:

The last knock-out was removed from the panel cover.

I will leave this breaker turned off until the rest of the circuit is finished.

 

A Few Thoughts On Fear And Electricity

A relative showed me how to replace a circuit breaker, and pointed out the dangers.  When the main breaker is turned off (in a typical one-panel house) there is still voltage in the panel, at the two big hot wires that feed the main breaker.

Touching these wires would require a lot of carelessness. Or stupidity. My only fear is accidentally touching the live metal parts with the wire I'm working on, possibly causing a short and a big nasty arc. Whenever I have shorted something, I've always jumped or jerked my hand away, and it's that involuntary reaction that I figure might pose the biggest risk of injury.

I have become a firm believer in organizing the house's electrical system by using subsidiary panels. My preference is too locate a sub-panel near the kitchen, in the garage, on the second floor, etc. I prefer to have all basic 120 volt circuits connected to one of several sub-panels, leaving the main panel to supply only the sub-panels and the larger 240 volt appliances (range, dryer, water heater, well pump)


Dryer Circuit Wiring and Hookup

By Donald Kerr

Dryer Circuit Wiring and Hookup

Wiring a Dryer Receptacle & Circuit

Dryer cable between circuit panel and dryer plug is 10 AWG, black/red/ white/ bare. X & Y are interchangeable, red and black wires are hot (live) wires, one wire on the X, and the other on the Y. The neutral (white) and the bare ground wire MUST be on there designated connection. In the diagram above the bare ground is indicated by a green line. The bare wire should also be grounded to the electrical box (if metallic).

Be sure to use the properly rated electrical box designed to be used with a dryer receptacle. The breaker used must be a dual (double) 30 amp 220v breaker. 220v breaker meaning that the breaker must be of the type that actually connects to both bus bars in the panel, every other bus lug in the panel is on the opposite phase of the incoming power line.


DRYER RECEPTACLE & CIRCUIT

The breaker used must be a dual (double) 30 amp 220v breaker. 220v breaker meaning that the breaker must be of the type that actually connects to both bus bars in the panel, every other bus lug in the panel is on the opposite phase of the incoming power line. refer to the picture below.

If you were to measure the voltage between a red lug and a black lug (they are not really those colors in the panel, just used here for explanation purposes) , you would measure 220v, if you were to measure between a black bus lug and a ground or neutral bus, you would measure 110v, and the same would hold true if you measure between a red bus lug and the ground or neutral bus.

The ground bus is a terminal block with many small holes where the bare ground (or green wire) can be connected and tightened into place with a screw.

The neutral bus is a terminal block also with many small holes where the white neutral wire can be connected and tightened into place with a screw.

A Safety Note about Breakers

A breaker designed to be used with 220v, is a dual (double) breaker that actually when mounted into the panel connects to both phases of the incoming power , in other words connects to both the red and black panel lugs (colors in illustration, your panel is not colored but will be alternating between phases from one lug to the next). Sometimes in some panels you may have a set of 4 breakers molded together and they mount in the panel over the 2 lugs , the middle 2 breakers would be the 2 30 amp breakers and the outer 2 could be 15 or 20 amp breakers for use in general purpose 110 v circuits. If you ask you local building or electrical supply depot for a dual 30 amp breaker for use in a 220v dryer circuit for this model/make breaker panel, they will be able to pick out the correct breaker for you. Please note, electrical panels are dangerous to work in, never touch any of the main bus lugs in the panel, they can kill! A breaker can be installed without physically touching the bus lugs. To be even safer you can switch the main breaker off to de-activate the panel which installing the breaker, use a second person to help with a flashlight if needed.

Also note that a 220 dual breaker has both breakers bridged so that one of the dual breakers will also trip the other side if it where to trip off.

The ground wire connects to the ground bus. Just look where all the other bare ground wires are going in the panel.

The white neutral wire gets connected to the neutral bus. Just look where all the other white wires are going in your panel. Should be on its own connection screw hole within the neutral bus.

The red and black wires from dryer cable connect to the dual 30 amp breaker, one to each of the dual breakers.

Dryer Cord - 3 wire hookup at Dryer

Photo used with permission from Jeff Worrall at Appliance Aid

3 wire dryer power systems are for use with existing ungrounded dryer receptacles mainly in older homes whose wiring in years gone by was not grounded.

This picture above shows a dryer cord (at the dryer end) with 3 wires only, No ground wire. The center wire of this cable is the neutral wire and the outer wires are hot live wires. The hot wires connect to the outer 2 connections the power terminal block of the dryer, does not matter which is which as long as one hot is connected to each of the outer terminal connectors.

The center wire (neutral wire) of the cable goes to the center connector. Since in this case the neutral serves as a neutral and a ground connection, a jumper band (ground strap) is also connected to the center terminal and to the frame of the dryer. A green wire could also be used to connect the center connector to the frame of the dryer.

In the example in the picture the dryer doesn't have color designation on the wires, follow direction above; if the dryer cord does have colored wires, white is the neutral wire to the center connector, the red and black wires are the hot live wires which connect to the 2 outer connections of the dryer terminal block, don't forget the ground strap or green wire jumper from the center connector to the dryer frame.

Note: All new dryer circuit/receptacle installations must be grounded, which means you would be using a 4 wire dryer cord with a new circuit install.

Dryer Cord - 4 wire hookup at Dryer


Photo used with permission from Jeff Worrall at Appliance Aid

A 4 wire dryer cord contains a black, red, white and green wire. The red and black wires are hot live wires and get connected to the 2 outer connectors on the dryers power terminal block, doesn't matter which is which as long as it is the outer two connectors. The green wire is a ground wire and gets connected to the frame of the dryer. The white wire is a neutral wire and must be connected to the center connector on the dryer power block. No ground strap is used in a 4 wire setup (grounded circuit). In the sample picture above the ground strap in folded over and is connected to the center connector but NO connection from it or jump to ground. The ground strap could also be removed if you wish as it is not needed in this installation.

Additonal notes

250-138 new branch circuits for ranges and dryers and 250-140 existing branch circuits for ranges and dryers.

Use a 30 amp 240 volt double pole breaker in the panel. Run a 10/3wGrnd Romex cable. This cable should be rated as a 10 awg cable with a red, black, white, and bare conductor in that cable. At the panel connect the black and red wire to the 30 amp double pole breaker. Connect the white and bare wire to the neutral bars in the panel.

Run the cable concealed in crawl or in attic or in walls.

At the dryer end use a 30 amp rated 4 prong dryer receptacle. The black connects to either the outside left connecting lug and the red connects to the other outside connecting lug. The white connects to the center connecting lug and the bare connects to the green connecting lug or screw. All these connections are inside that 30 rated 4 prong dryer receptacle.

The pigtail to your dryer will have to be changed to a 4 prong pigtail with the two outside cables connecting to the two outside screws found on the connecting block inside the dryer. The center white conductor is connected to the center screw of that dryer connecting block. the bare or green conductor connects to the metal frame of the dryer on a green screw provided.

The above is for a new branch circuit serving an existing or new dryer.

If you can move an existing three prong dryer to your new desired location then you may use this three prong recetacle still as existing only if the cable is an SE type cable with a red, black, and bare conductor. This bare conductor must wrap around the black and red wire as a protector within that SE cable. If you have a cable that is Romex but not with the identification of being an SE cable written on the side of that cable, or the bare wire does not wrap the black and red conductors, then you must upgrade that branch circuit to the new requirements using a four conductor cable and a four prong receptacle as discribed above at the beginning of this article.

If you are using a three prong receptacle as existing then the pigtail must be a three prong pigtail with the two outside wires of that pigtail connected to the two outside screws of the connecting block found in the dryer. The center conductor of the pigtail is connected to the center screw of that same connecting block inside the dryer. There must also be a green jumper wire installed between the center connection on that connecting block in the dryer and the metal frame of the dryer on a green screw.

 


Dryer Circuit Wiring and Hookup By Donald Kerr

Digg Del.icio.us Reddit Stumbleupon Share it Get help Wiring a Dryer Receptacle & Circuit Dryer cable between circuit panel and dryer plug is 10 AWG, black/red/ white/ bare. X & Y are interchangeable, red and black wires are hot (live) wires, one wire on the X, and the other on the Y. The neutral (white) and the bare ground wire MUST be on there designated connection. In the diagram above the bare ground is indicated by a green line. The bare wire should also be grounded to the electrical box (if metallic).

Be sure to use the properly rated electrical box designed to be used with a dryer receptacle. The breaker used must be a dual (double) 30 amp 220v breaker. 220v breaker meaning that the breaker must be of the type that actually connects to both bus bars in the panel, every other bus lug in the panel is on the opposite phase of the incoming power line.

DRYER RECEPTACLE & CIRCUIT

The breaker used must be a dual (double) 30 amp 220v breaker. 220v breaker meaning that the breaker must be of the type that actually connects to both bus bars in the panel, every other bus lug in the panel is on the opposite phase of the incoming power line. refer to the picture below.

If you were to measure the voltage between a red lug and a black lug (they are not really those colors in the panel, just used here for explanation purposes) , you would measure 220v, if you were to measure between a black bus lug and a ground or neutral bus, you would measure 110v, and the same would hold true if you measure between a red bus lug and the ground or neutral bus.

The ground bus is a terminal block with many small holes where the bare ground (or green wire) can be connected and tightened into place with a screw.

The neutral bus is a terminal block also with many small holes where the white neutral wire can be connected and tightened into place with a screw.

A Safety Note about Breakers A breaker designed to be used with 220v, is a dual (double) breaker that actually when mounted into the panel connects to both phases of the incoming power , in other words connects to both the red and black panel lugs (colors in illustration, your panel is not colored but will be alternating between phases from one lug to the next). Sometimes in some panels you may have a set of 4 breakers molded together and they mount in the panel over the 2 lugs , the middle 2 breakers would be the 2 30 amp breakers and the outer 2 could be 15 or 20 amp breakers for use in general purpose 110 v circuits. If you ask you local building or electrical supply depot for a dual 30 amp breaker for use in a 220v dryer circuit for this model/make breaker panel, they will be able to pick out the correct breaker for you. Please note, electrical panels are dangerous to work in, never touch any of the main bus lugs in the panel, they can kill! A breaker can be installed without physically touching the bus lugs. To be even safer you can switch the main breaker off to de-activate the panel which installing the breaker, use a second person to help with a flashlight if needed.

Also note that a 220 dual breaker has both breakers bridged so that one of the dual breakers will also trip the other side if it where to trip off.

The ground wire connects to the ground bus. Just look where all the other bare ground wires are going in the panel.

The white neutral wire gets connected to the neutral bus. Just look where all the other white wires are going in your panel. Should be on its own connection screw hole within the neutral bus.

The red and black wires from dryer cable connect to the dual 30 amp breaker, one to each of the dual breakers.

Dryer Cord - 3 wire hookup at Dryer

Photo used with permission from Jeff Worrall at Appliance Aid

3 wire dryer power systems are for use with existing ungrounded dryer receptacles mainly in older homes whose wiring in years gone by was not grounded.

This picture above shows a dryer cord (at the dryer end) with 3 wires only, No ground wire. The center wire of this cable is the neutral wire and the outer wires are hot live wires. The hot wires connect to the outer 2 connections the power terminal block of the dryer, does not matter which is which as long as one hot is connected to each of the outer terminal connectors.

The center wire (neutral wire) of the cable goes to the center connector. Since in this case the neutral serves as a neutral and a ground connection, a jumper band (ground strap) is also connected to the center terminal and to the frame of the dryer. A green wire could also be used to connect the center connector to the frame of the dryer.

In the example in the picture the dryer doesn't have color designation on the wires, follow direction above; if the dryer cord does have colored wires, white is the neutral wire to the center connector, the red and black wires are the hot live wires which connect to the 2 outer connections of the dryer terminal block, don't forget the ground strap or green wire jumper from the center connector to the dryer frame.

Note: All new dryer circuit/receptacle installations must be grounded, which means you would be using a 4 wire dryer cord with a new circuit install.

Dryer Cord - 4 wire hookup at Dryer

Photo used with permission from Jeff Worrall at Appliance Aid

A 4 wire dryer cord contains a black, red, white and green wire. The red and black wires are hot live wires and get connected to the 2 outer connectors on the dryers power terminal block, doesn't matter which is which as long as it is the outer two connectors. The green wire is a ground wire and gets connected to the frame of the dryer. The white wire is a neutral wire and must be connected to the center connector on the dryer power block. No ground strap is used in a 4 wire setup (grounded circuit). In the sample picture above the ground strap in folded over and is connected to the center connector but NO connection from it or jump to ground. The ground strap could also be removed if you wish as it is not needed in this installation.

Additonal notes 250-138 new branch circuits for ranges and dryers and 250-140 existing branch circuits for ranges and dryers.

Use a 30 amp 240 volt double pole breaker in the panel. Run a 10/3wGrnd Romex cable. This cable should be rated as a 10 awg cable with a red, black, white, and bare conductor in that cable. At the panel connect the black and red wire to the 30 amp double pole breaker. Connect the white and bare wire to the neutral bars in the panel.

Run the cable concealed in crawl or in attic or in walls.

At the dryer end use a 30 amp rated 4 prong dryer receptacle. The black connects to either the outside left connecting lug and the red connects to the other outside connecting lug. The white connects to the center connecting lug and the bare connects to the green connecting lug or screw. All these connections are inside that 30 rated 4 prong dryer receptacle.

The pigtail to your dryer will have to be changed to a 4 prong pigtail with the two outside cables connecting to the two outside screws found on the connecting block inside the dryer. The center white conductor is connected to the center screw of that dryer connecting block. the bare or green conductor connects to the metal frame of the dryer on a green screw provided.

The above is for a new branch circuit serving an existing or new dryer.

If you can move an existing three prong dryer to your new desired location then you may use this three prong recetacle still as existing only if the cable is an SE type cable with a red, black, and bare conductor. This bare conductor must wrap around the black and red wire as a protector within that SE cable. If you have a cable that is Romex but not with the identification of being an SE cable written on the side of that cable, or the bare wire does not wrap the black and red conductors, then you must upgrade that branch circuit to the new requirements using a four conductor cable and a four prong receptacle as discribed above at the beginning of this article.

If you are using a three prong receptacle as existing then the pigtail must be a three prong pigtail with the two outside wires of that pigtail connected to the two outside screws of the connecting block found in the dryer. The center conductor of the pigtail is connected to the center screw of that same connecting block inside the dryer. There must also be a green jumper wire installed between the center connection on that connecting block in the dryer and the metal frame of the dryer on a green screw


Electrical Wiring in the Home - Rewire 3 prong dryer to 4 prong

Question Master Bob

I have a 220 volt 3 prong dryer that I now need to plug into a 220 volt 4 prong receptacle. On the back there is a label stating that the dryer is 'neutrally grounded' and I notice that the existing three prong plug only hooks up to the two hots and a neutral in the back of the dryer. A green wire comes out of the dryer and is attached to the dryer housing on the back near where the cord hook up is. My first question is how is this appliance grounded now and how should I hook up a new four prong plug (also how can I test to ensure the system is wired/grounded correctly). Thank you,

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Answer Hi Quinn,

Under the new Codes...all dryers (and stoves/ovens) must now be 4 wire....having a seperate neutral and ground wire in NEW construction. In decades past, the neutral was allowed to serve as both - the neutral and ground - typically by means of a solid metal strap or wire strap that bonded that connection to the metal frame of the dryer. This sounds as if it is the case in your existing dryer...which was typical.

But...the old arrangement wasn't always reliable...and a seperate dedicated ground provides a greater safety path in the event of a fault inside the dryer (lowering the chance the user may get a shock when touching the frame of the dryer).

To modify your existing 3 prong dryer over to 4....you'll need to remove the 3 wire - disconnect the ground strap (or wire) that bonds the neutral to the frame of the dryer...and install your 4 wire so that you'll have (from left to right) one hot, one neutral, one hot connection...and connect the ground directly to he frame of the dryer (there is usually a green screw near the dryer connection block for this ground)

For more on this - with an illustration, see:

http://www.american-appliance.com/service_pages/electric_dryer_cord.htm

When done properly, you can test for correct wiring and connection with an ohm-meter (continuity check)...by checking for continuity from the ground prong on the plug to the frame of the dryer...you should see continuity. Then check for continuity from the neutral prong on the plug to the frame...you should NOT see continuity....nor should you see any continuity between the neutral connection at the wiring block to the metal frame.

The whole purpose of the Code change to the 4 wire is to seperate the two.

Service Tips

Electric Dryer How To Cord Date: Wednesday 24 January, 2007

Electric Dryer How To Hook Up Cord

For Three Prong Cords the Center cord wire goes on the center terminal, the left on the left , and the right on the right.

Note: There should be a ground strap or wire that runs from the center terminal to the dryer case.

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For Four Prong Cords the White cord wire goes in the center, the Red on the Right, the Black on the Left. The green cord wire goes to the case or the external ground screw.

Note: Be sure to disconnect the ground wire or strap that runs from the center terminal to the case. In this Photo (A Whirlpool Dryer) I have ran the wire that runs from the center terminal, the Light Green wire, back to itself rather than cutting it off, just incase I need to put a 3 prong cord back on it some day. The whole purpose of this 3 prong / 4 prong thing is it separates the neutral from the ground.

3 Prong Cord Whirlpool Dryer Example 4 Prong Cord Whirlpool Dryer Example

 

Electric Dryer How To Hook Up Cord

 

For Three Prong Cords
the Center cord wire goes on the center terminal,
the left on the left ,
and the right on the right.

Note: There should be a ground strap or wire that runs from the center terminal to the dryer case.



For Four Prong Cords
the White cord wire goes in the center,
the Red on the Right,
the Black on the Left.
The green cord wire goes to the case or the external ground screw.

Note: Be sure to disconnect the ground wire or strap that runs from the center terminal to the case. In this Photo (A Whirlpool Dryer) I have ran the wire that runs from the center terminal, the Light Green wire, back to itself rather than cutting it off, just incase I need to put a 3 prong cord back on it some day. The whole purpose of this 3 prong / 4 prong thing is it separates the neutral from the ground.

 
3 Prong Cord Whirlpool Dryer Example
3 Prong Cord Whirlpool Dryer Example

4 Prong Cord Whirlpool Dryer Example

4 Prong Cord Whirlpool Dryer Example

Hope this helps,....if you need more details, please follow-up.

Best Wishes,

Bob Osgood Master Electrician


220v welder 3 prong into dryer 4 prong?

Jim Naysium03-13-2006, 03:05 PM I have read about how to hook up my dryer to a 4 prong to make it match my 4 prong outlet and lucky for me, it sounds like you guys(gals)really know what you're talking about! I have a 30-120amp 230V mig welder that came out of the box with no male plug. It only has 3 wires though and my garage outlet,(wired in 2001 new construction) has a 4 prong outlet. I have replaced 110v light fixtures and added on extra outlets in my basement, but never messed with 220 before. I have to admit that it kind of scares me! :dead: I would love to hear from you! Thanks!

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SOcRatEs03-13-2006, 07:15 PM Well I'v yet to run in to a computer that runs on 220, though I have run a split leg w/ common ground to supply a server sytem. What part of the world are you in?

You'll need a pigtail adaptor from the four prong 220 outlet that adapts to a three, then wire the mig to a standard 220 three prong male. Be sure to know what the amp ratings are on the dryer/220 circut breaker. In some cases you may need to have a 440 split leg to run high end migs. Most migs are 50 to 140 amps single/double phase and dryers tend to be 40 amp single phase.

This LINK (http://216.130.168.108/showthread.php?t=812) may be helpful.

G'Luck & watchout for the blew smoke :hotbounce

 

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