doityourselfchristmas.com - User contributions [en]

Shared Neutral Cables

2008-02-06T15:50:01Z

Jeffmill: /* Split Controllers */

''This is still a work in progress. Pictures still need to be added.'' "Please see the discussion page for an explanation"
==Introduction==
One way to save money and setup time on your display is to have the neutral line shared among several channels. As jeffmill has shown, however, there are many considerations that come into play to keep your display safe when using them. He also tells about some of his uses of Shared Neutral Cables in his display.

===Disclaimers===
All the standard [[Disclaimers]] apply. If you have any questions about the use of electrical wiring and its construction you should consult a qualified electrical professional who is licensed and bonded who is knowledgeable of the electrical codes in your area. The information that follows is not to be considered a guide, but rather a discussion about the safe use of multiple circuit cables for the connection of temporary seasonal lighting. You are solely responsible for any use of this information. DoItYourselfChristmas (Hereafter known as DIYC) and its members take no responsibility for any damage or harm that may occur from using the information found herein.

==Safety Considerations==
There is no reason whatsoever to fear using a single neutral along with several strands of a smaller gauge wire as the hots, as long as a few safety precautions are followed.

===Using SPT Outdoors===
The use of SPT outdoors is a long standing debate with folks setting on both sides of the fence. Regardless of what the concerns are, the only issue here is the lack of UV protection on the wire. If you toss an indoor rated extension cord (zip cord, SPT) out in the sunlight it will eventually break down the insulation and short the conductors. No more, no less. Every one of my cables is wrapped in UV protected 3/4" black electrical tape.

I think using SPT and/or THHN is acceptable and safe to use in these cables. The indoor/outdoor status becomes a non issue when you alleviate the UV problem with UV protection. 'nuff said.

===Wire Gauge===
The neutral line should be of sufficient gauge for the total load of every circuit in the cable shared by that neutral. You must know the gauge and capacity of the wire you use for the hots, and multiply that by the number of conductors you will use in your neutral to determine the gauge of it. It is a common practice to design an 80% loading into every aspect of electrical wiring in a home - that gives you a 20% buffer as a safety margin.

Take into consideration any future additions you are planning. It may be less costly to build for a larger capacity, as smaller gauge wire can be more expensive if it is not a commonly stocked item. Also, keep in mind that SPT I or SPT II is not an indication of the capacity of the wire, it only describes the amount of insulation between the wires.

===Multi-Conductor Wire Capacity===
The NEC provides a reduction in the overall current carrying capacity of conductors in a multi-conductor cable such as this there is a mutual inductance, or interaction between the conductors that reduces their load carrying capacity. I believe that the 80% safety margin is sufficient to allow for this issue. Interpret it this way: If you have a conductor that is rated for 10 amps, design your construction so that it will carry 8 amps maximum.

===Cable Quality===
Ensure quality when constructing the cables. It is my personal opinion that they should be constructed by carefully soldering the connections. I also use heat-shrink tubing for its insulating qualities, along with the neatness of the connection which might otherwise become a big bulky wart in the cable where solder joints are located. I always do the neutral connection first, and then try to offset the position of the hots enough so they don't add to the bulk of the neutral connection. These cables will be used over and over again, year after year. Taking the time to construct them well will pay off in the end.

===Cable Length===
Ensure that you have enough length to prevent them from being tripped over, or pulled. When I designed the cables for the major items like the mega tree, and the bundled group of 15 mini trees I looked around to see if there was any other possible locations I would want to place them. I made the cable length to fit as much distance as possible within reason. Since I use Molex connectors on the controller end the possibility of adding extensions exists, so the length isn't written in stone for me.

===GFCI===
If you don't use GFCI, you will probably lose a fuse or a Triac that thinks it’s a fuse. GFCI is a very simple differential protection scheme. It monitors the flow of current to and from a load (load = lights) If the current flowing to the load does not equal the flow back from the load down to a very minute quantity, it trips open at a very high speed.

Dropping a set of lights into a bucket of water that does not have a path to ground or some other return path to the source will not trip a GFCI. That is because the current it monitors will still be equal, and not considered a differential fault. In a ground fault, some of the current flowing to the load bypasses its normal path back from the load and travels through the ground instead. That results in an unequal measurement in the scheme = TRIP! Design cables so you can keep the connections off the ground, where rain water can flow through them and drip away. This will prevent ground faults that will trip GFCI.

GFCIs do not only trip for ground faults. It can occur when the current leaks over to another circuit and finds a return path that is not its normal course. You can prevent this in a multi-conductor scheme by ensuring quality in your construction, and also by keeping all the conductors in the cable on a single GFCI.

===Foreign Power===
====Voltage====
The use of my design of cable is solely for US power systems. I have no experience in foreign power systems. There are other folks that will surely be able to help the 220V users. When powering one of these cables with a common neutral always ensure that you are on a single hot leg of your electrical service in a given cable. This will prevent the possibility of 220Vac if the neutral becomes unbonded anywhere.

====Split Controllers====
Some of the controller manufacturers design their products to be used in Europe, the UK and Australia, with the controller divided down the middle that can have 2 opposing legs of 120Vac powering each side, in effect having 220Vac powering the board. This is not an unsafe practice because the boards were designed for it, and 220Vac is the standard in foreign applications. However, when given the choice, I believe it's always a good idea to choose the safer option and try to minimize the possible dangers associated with with higher voltages by keeping a single leg on a controller. My concern for this is directly related to the construction of these cables. If you were to set up a 16 channel controller with two opposing legs then place 12 of the channels in a single cable as I did in my mega tree design, you have 220Vac in the cable. Squirrel chews the cable, you pick up the cable, the path provided by the squirrel lets 220Vac cross the upper portion of your torso on the way to ground or worse you get 120 in your left hand and opposing 120 in your right... Then just before everything fades to black, you see two squirrels doing that funny hand-slap dance from the car insurance commercial...

==Cable Construction==
This is an example of how shared neutrals can be used in your display.
===Mega Tree===
My first cable is directly based on the design of a control cable used in the electrical industry. I chose the number of slices for my Mega Tree based on the design of this cable. It utilizes three sets of 4 #16 conductors (or two strands of SPT) with a single #12 THHN common neutral for each set. Altogether there are 15 conductors to handle the work of 24. At one end of a 40' cable there are 12 Dollar Store three-outlet extension cords, spray painted with Krylon Fusion to UV protect them. At the other end there is a set of 15 pin Molex connectors with 12 strands of #14 THHN and 3 of #12, approximately 3' long. I connect the 3' piece and female connector to the controllers. It makes for a quick connection to the tree. There are 5 of these cables to light 60 channels. 12 slices each of Red, Green, Yellow, Blue and Clear minis. Each slice of colored lights is 150 count, and the clear are 200 count.

===SSR Connections===
The second cable is a little more complicated. It combines the AC power to remotely located SSRs, along with the wire connected to the output channels to power my rope light candy canes. Once again I used Molex connectors, this time not only for the end but also to connect the SSRs to the circuit. It is a very quick way to snap in/out SSRs from the scheme even though I haven't had any failures that required this.

===Candy canes===
I calculated the total load of all the rope light combined in my canes and ran a single strand of THHN of sufficient gauge from a terminal strip at the power source. This runs all the way out to the corner and across the front of my yard. Then I marked the strand to evenly space 24 canes which came out to a little over 2' per division.

I cut 24 pieces of heat shrink about 1 1/2" each and slid them onto the wire about a foot down from the end. I stripped the very end off about 3/4" and soldered the 2' neutral for the first cane to it. Heat shrink and move everything over a couple feet. Strip 3/4" off the next mark, solder the next neutral, heat shrink and move on. 24 times and the basic cane locations are in place along with a 2' pigtail for each neutral.

Next I located an SSR just after the fourth cane. Measure out four pieces of wire to power canes 1, 2, 3 and 4. Cut them to length and begin to wrap them with 1/2" electrical tape. Leave enough conductor to tin the leads and stab them into the end of the rope light. At the place where they connect to the SSR they can be landed into the screw terminals, or in my case Molex pins were crimped and soldered on. Add one power wire all the way back to the terminal strip for the SSR and move down 4 to just after the 8th cane.

Repeat the process for the 4 cane hot leads and tap off the power wire to the first SSR. Move down four canes, but this time run a new power wire. To break it up into bundles of eight I cut the power wire and neutral just after the 2nd SSR and added a 2 pin Molex connector. The same thing just after SSR 4 and add a 4 pin Molex. Then cut all 4 just after the last cane and add another 4 pin Molex. One more 4 pin Molex at the terminal strip and power source. The SSRs are placed in a Pod made from PVC pipe and end caps wire tied to a stake. It’s a very neat design that can be easily maintained and repaired. Everything bundled up in a single cable. Now all I have to do is get the other 14 Candy Canes converted over to Ropelight….

The difference in cost to wire my Mega Tree cables was offset by the mere fact that I decided to add Molex connectors to them. I believe I saved at least 50% had I not added all the bells and whistles. I cannot claim a savings on the design of the Candy Canes either as the wire used was scrap that I recovered from a dumpster. However, this method will save you money, and will make the Annual set-up and take-down easier.

Shared Neutral Cables

2008-02-06T15:33:10Z

Jeffmill: /* Cable Length */

''This is still a work in progress. Pictures still need to be added.'' "Please see the discussion page for an explanation"
==Introduction==
One way to save money and setup time on your display is to have the neutral line shared among several channels. As jeffmill has shown, however, there are many considerations that come into play to keep your display safe when using them. He also tells about some of his uses of Shared Neutral Cables in his display.

===Disclaimers===
All the standard [[Disclaimers]] apply. If you have any questions about the use of electrical wiring and its construction you should consult a qualified electrical professional who is licensed and bonded who is knowledgeable of the electrical codes in your area. The information that follows is not to be considered a guide, but rather a discussion about the safe use of multiple circuit cables for the connection of temporary seasonal lighting. You are solely responsible for any use of this information. DoItYourselfChristmas (Hereafter known as DIYC) and its members take no responsibility for any damage or harm that may occur from using the information found herein.

==Safety Considerations==
There is no reason whatsoever to fear using a single neutral along with several strands of a smaller gauge wire as the hots, as long as a few safety precautions are followed.

===Using SPT Outdoors===
The use of SPT outdoors is a long standing debate with folks setting on both sides of the fence. Regardless of what the concerns are, the only issue here is the lack of UV protection on the wire. If you toss an indoor rated extension cord (zip cord, SPT) out in the sunlight it will eventually break down the insulation and short the conductors. No more, no less. Every one of my cables is wrapped in UV protected 3/4" black electrical tape.

I think using SPT and/or THHN is acceptable and safe to use in these cables. The indoor/outdoor status becomes a non issue when you alleviate the UV problem with UV protection. 'nuff said.

===Wire Gauge===
The neutral line should be of sufficient gauge for the total load of every circuit in the cable shared by that neutral. You must know the gauge and capacity of the wire you use for the hots, and multiply that by the number of conductors you will use in your neutral to determine the gauge of it. It is a common practice to design an 80% loading into every aspect of electrical wiring in a home - that gives you a 20% buffer as a safety margin.

Take into consideration any future additions you are planning. It may be less costly to build for a larger capacity, as smaller gauge wire can be more expensive if it is not a commonly stocked item. Also, keep in mind that SPT I or SPT II is not an indication of the capacity of the wire, it only describes the amount of insulation between the wires.

===Multi-Conductor Wire Capacity===
The NEC provides a reduction in the overall current carrying capacity of conductors in a multi-conductor cable such as this there is a mutual inductance, or interaction between the conductors that reduces their load carrying capacity. I believe that the 80% safety margin is sufficient to allow for this issue. Interpret it this way: If you have a conductor that is rated for 10 amps, design your construction so that it will carry 8 amps maximum.

===Cable Quality===
Ensure quality when constructing the cables. It is my personal opinion that they should be constructed by carefully soldering the connections. I also use heat-shrink tubing for its insulating qualities, along with the neatness of the connection which might otherwise become a big bulky wart in the cable where solder joints are located. I always do the neutral connection first, and then try to offset the position of the hots enough so they don't add to the bulk of the neutral connection. These cables will be used over and over again, year after year. Taking the time to construct them well will pay off in the end.

===Cable Length===
Ensure that you have enough length to prevent them from being tripped over, or pulled. When I designed the cables for the major items like the mega tree, and the bundled group of 15 mini trees I looked around to see if there was any other possible locations I would want to place them. I made the cable length to fit as much distance as possible within reason. Since I use Molex connectors on the controller end the possibility of adding extensions exists, so the length isn't written in stone for me.

===GFCI===
If you don't use GFCI, you will probably lose a fuse or a Triac that thinks it’s a fuse. GFCI is a very simple differential protection scheme. It monitors the flow of current to and from a load (load = lights) If the current flowing to the load does not equal the flow back from the load down to a very minute quantity, it trips open at a very high speed.

Dropping a set of lights into a bucket of water that does not have a path to ground or some other return path to the source will not trip a GFCI. That is because the current it monitors will still be equal, and not considered a differential fault. In a ground fault, some of the current flowing to the load bypasses its normal path back from the load and travels through the ground instead. That results in an unequal measurement in the scheme = TRIP! Design cables so you can keep the connections off the ground, where rain water can flow through them and drip away. This will prevent ground faults that will trip GFCI.

GFCIs do not only trip for ground faults. It can occur when the current leaks over to another circuit and finds a return path that is not its normal course. You can prevent this in a multi-conductor scheme by ensuring quality in your construction, and also by keeping all the conductors in the cable on a single GFCI.

===Foreign Power===
====Voltage====
The use of my design of cable is solely for US power systems. I have no experience in foreign power systems. There are other folks that will surely be able to help the 220V users. When powering one of these cables with a common neutral always ensure that you are on a single hot leg of your electrical service in a given cable. This will prevent the possibility of 220Vac if the neutral becomes unbonded anywhere.

====Split Controllers====
Some of the controller manufacturers design their products to be used in Europe, the UK and Australia, and that some of the controllers are divided down the middle and can have 2 opposing legs of 120Vac powering each side, rather than using 220VAC. That is not an unsafe practice. Some may say this is not nessecary because the boards were designed for it, and 220Vac is the standard in foreign applications. However, when given the choice, it is always a good idea to choose the safer option.

==Cable Construction==
This is an example of how shared neutrals can be used in your display.
===Mega Tree===
My first cable is directly based on the design of a control cable used in the electrical industry. I chose the number of slices for my Mega Tree based on the design of this cable. It utilizes three sets of 4 #16 conductors (or two strands of SPT) with a single #12 THHN common neutral for each set. Altogether there are 15 conductors to handle the work of 24. At one end of a 40' cable there are 12 Dollar Store three-outlet extension cords, spray painted with Krylon Fusion to UV protect them. At the other end there is a set of 15 pin Molex connectors with 12 strands of #14 THHN and 3 of #12, approximately 3' long. I connect the 3' piece and female connector to the controllers. It makes for a quick connection to the tree. There are 5 of these cables to light 60 channels. 12 slices each of Red, Green, Yellow, Blue and Clear minis. Each slice of colored lights is 150 count, and the clear are 200 count.

===SSR Connections===
The second cable is a little more complicated. It combines the AC power to remotely located SSRs, along with the wire connected to the output channels to power my rope light candy canes. Once again I used Molex connectors, this time not only for the end but also to connect the SSRs to the circuit. It is a very quick way to snap in/out SSRs from the scheme even though I haven't had any failures that required this.

===Candy canes===
I calculated the total load of all the rope light combined in my canes and ran a single strand of THHN of sufficient gauge from a terminal strip at the power source. This runs all the way out to the corner and across the front of my yard. Then I marked the strand to evenly space 24 canes which came out to a little over 2' per division.

I cut 24 pieces of heat shrink about 1 1/2" each and slid them onto the wire about a foot down from the end. I stripped the very end off about 3/4" and soldered the 2' neutral for the first cane to it. Heat shrink and move everything over a couple feet. Strip 3/4" off the next mark, solder the next neutral, heat shrink and move on. 24 times and the basic cane locations are in place along with a 2' pigtail for each neutral.

Next I located an SSR just after the fourth cane. Measure out four pieces of wire to power canes 1, 2, 3 and 4. Cut them to length and begin to wrap them with 1/2" electrical tape. Leave enough conductor to tin the leads and stab them into the end of the rope light. At the place where they connect to the SSR they can be landed into the screw terminals, or in my case Molex pins were crimped and soldered on. Add one power wire all the way back to the terminal strip for the SSR and move down 4 to just after the 8th cane.

Repeat the process for the 4 cane hot leads and tap off the power wire to the first SSR. Move down four canes, but this time run a new power wire. To break it up into bundles of eight I cut the power wire and neutral just after the 2nd SSR and added a 2 pin Molex connector. The same thing just after SSR 4 and add a 4 pin Molex. Then cut all 4 just after the last cane and add another 4 pin Molex. One more 4 pin Molex at the terminal strip and power source. The SSRs are placed in a Pod made from PVC pipe and end caps wire tied to a stake. It’s a very neat design that can be easily maintained and repaired. Everything bundled up in a single cable. Now all I have to do is get the other 14 Candy Canes converted over to Ropelight….

The difference in cost to wire my Mega Tree cables was offset by the mere fact that I decided to add Molex connectors to them. I believe I saved at least 50% had I not added all the bells and whistles. I cannot claim a savings on the design of the Candy Canes either as the wire used was scrap that I recovered from a dumpster. However, this method will save you money, and will make the Annual set-up and take-down easier.

Display Construction

2008-02-06T15:25:33Z

Jeffmill: Added Shared Neutral Cables to navigation

This is the page to talk about how to build the things that people see in your display. If you have custom made anything for your display write an article about it in step by step instructions and post it here. We are always looking for cool and unique ideas and items to add to our displays. Remember a picture is worth 1000 words!

[[Hookup]]: An organized way to wire your display

[[Mini Trees]]: What Mini Trees are and how to make them.

Easy [[Light Arch]]: How to build a 10 channel Light Arch

[[Happy Holidays Sign]] : How to build a Happy Holidays sign using PVC

[[Shorten Mini Lights]] : How you can cut or shorten a set of 100 Mini style Christmas lights

[[Extension Cord Adapters]] : How you can adapt a regular extension cord to handle two control channels

[[Plywood Cut Outs]]

[[Shared Neutral Cables]] : Specialized cables that can combine multiple channel into a bundle

Shared Neutral Cables

2008-02-06T01:34:05Z

Jeffmill:

''This is still a work in progress. Pictures still need to be added.'' "Please see the discussion page for an explanation"
==Introduction==
One way to save money and setup time on your display is to have the neutral line shared among several channels. As jeffmill has shown, however, there are many considerations that come into play to keep your display safe when using them. He also tells about some of his uses of Shared Neutral Cables in his display.

===Disclaimers===
All the standard [[Disclaimers]] apply. If you have any questions about the use of electrical wiring and its construction you should consult a qualified electrical professional who is licensed and bonded who is knowledgeable of the electrical codes in your area. The information that follows is not to be considered a guide, but rather a discussion about the safe use of multiple circuit cables for the connection of temporary seasonal lighting. You are solely responsible for any use of this information. DoItYourselfChristmas (Hereafter known as DIYC) and its members take no responsibility for any damage or harm that may occur from using the information found herein.

==Safety Considerations==
There is no reason whatsoever to fear using a single neutral along with several strands of a smaller gauge wire as the hots, as long as a few safety precautions are followed.

===Using SPT Outdoors===
The use of SPT outdoors is a long standing debate with folks setting on both sides of the fence. Regardless of what the concerns are, the only issue here is the lack of UV protection on the wire. If you toss an indoor rated extension cord (zip cord, SPT) out in the sunlight it will eventually break down the insulation and short the conductors. No more, no less. Every one of my cables is wrapped in UV protected 3/4" black electrical tape.

I think using SPT and/or THHN is acceptable and safe to use in these cables. The indoor/outdoor status becomes a non issue when you alleviate the UV problem with UV protection. 'nuff said.

===Wire Gauge===
The neutral line should be of sufficient gauge for the total load of every circuit in the cable shared by that neutral. You must know the gauge and capacity of the wire you use for the hots, and multiply that by the number of conductors you will use in your neutral to determine the gauge of it. It is a common practice to design an 80% loading into every aspect of electrical wiring in a home - that gives you a 20% buffer as a safety margin.

Take into consideration any future additions you are planning. It may be less costly to build for a larger capacity, as smaller gauge wire can be more expensive if it is not a commonly stocked item. Also, keep in mind that SPT I or SPT II is not an indication of the capacity of the wire, it only describes the amount of insulation between the wires.

===Multi-Conductor Wire Capacity===
The NEC provides a reduction in the overall current carrying capacity of conductors in a multi-conductor cable such as this there is a mutual inductance, or interaction between the conductors that reduces their load carrying capacity. I believe that the 80% safety margin is sufficient to allow for this issue. Interpret it this way: If you have a conductor that is rated for 10 amps, design your construction so that it will carry 8 amps maximum.

===Cable Quality===
Ensure quality when constructing the cables. It is my personal opinion that they should be constructed by carefully soldering the connections. I also use heat-shrink tubing for its insulating qualities, along with the neatness of the connection which might otherwise become a big bulky wart in the cable where solder joints are located. I always do the neutral connection first, and then try to offset the position of the hots enough so they don't add to the bulk of the neutral connection. These cables will be used over and over again, year after year. Taking the time to construct them well will pay off in the end.

===Cable Length===
Ensure that you have enough length to prevent them from being tripped over, or pulled.

===GFCI===
If you don't use GFCI, you will probably lose a fuse or a Triac that thinks it’s a fuse. GFCI is a very simple differential protection scheme. It monitors the flow of current to and from a load (load = lights) If the current flowing to the load does not equal the flow back from the load down to a very minute quantity, it trips open at a very high speed.

Dropping a set of lights into a bucket of water that does not have a path to ground or some other return path to the source will not trip a GFCI. That is because the current it monitors will still be equal, and not considered a differential fault. In a ground fault, some of the current flowing to the load bypasses its normal path back from the load and travels through the ground instead. That results in an unequal measurement in the scheme = TRIP! Design cables so you can keep the connections off the ground, where rain water can flow through them and drip away. This will prevent ground faults that will trip GFCI.

GFCIs do not only trip for ground faults. It can occur when the current leaks over to another circuit and finds a return path that is not its normal course. You can prevent this in a multi-conductor scheme by ensuring quality in your construction, and also by keeping all the conductors in the cable on a single GFCI.

===Foreign Power===
====Voltage====
The use of my design of cable is solely for US power systems. I have no experience in foreign power systems. There are other folks that will surely be able to help the 220V users. When powering one of these cables with a common neutral always ensure that you are on a single hot leg of your electrical service in a given cable. This will prevent the possibility of 220Vac if the neutral becomes unbonded anywhere.

====Split Controllers====
Some of the controller manufacturers design their products to be used in Europe, the UK and Australia, and that some of the controllers are divided down the middle and can have 2 opposing legs of 120Vac powering each side, rather than using 220VAC. That is not an unsafe practice. Some may say this is not nessecary because the boards were designed for it, and 220Vac is the standard in foreign applications. However, when given the choice, it is always a good idea to choose the safer option.

==Cable Construction==
This is an example of how shared neutrals can be used in your display.
===Mega Tree===
My first cable is directly based on the design of a control cable used in the electrical industry. I chose the number of slices for my Mega Tree based on the design of this cable. It utilizes three sets of 4 #16 conductors (or two strands of SPT) with a single #12 THHN common neutral for each set. Altogether there are 15 conductors to handle the work of 24. At one end of a 40' cable there are 12 Dollar Store three-outlet extension cords, spray painted with Krylon Fusion to UV protect them. At the other end there is a set of 15 pin Molex connectors with 12 strands of #14 THHN and 3 of #12, approximately 3' long. I connect the 3' piece and female connector to the controllers. It makes for a quick connection to the tree. There are 5 of these cables to light 60 channels. 12 slices each of Red, Green, Yellow, Blue and Clear minis. Each slice of colored lights is 150 count, and the clear are 200 count.

===SSR Connections===
The second cable is a little more complicated. It combines the AC power to remotely located SSRs, along with the wire connected to the output channels to power my rope light candy canes. Once again I used Molex connectors, this time not only for the end but also to connect the SSRs to the circuit. It is a very quick way to snap in/out SSRs from the scheme even though I haven't had any failures that required this.

===Candy canes===
I calculated the total load of all the rope light combined in my canes and ran a single strand of THHN of sufficient gauge from a terminal strip at the power source. This runs all the way out to the corner and across the front of my yard. Then I marked the strand to evenly space 24 canes which came out to a little over 2' per division.

I cut 24 pieces of heat shrink about 1 1/2" each and slid them onto the wire about a foot down from the end. I stripped the very end off about 3/4" and soldered the 2' neutral for the first cane to it. Heat shrink and move everything over a couple feet. Strip 3/4" off the next mark, solder the next neutral, heat shrink and move on. 24 times and the basic cane locations are in place along with a 2' pigtail for each neutral.

Next I located an SSR just after the fourth cane. Measure out four pieces of wire to power canes 1, 2, 3 and 4. Cut them to length and begin to wrap them with 1/2" electrical tape. Leave enough conductor to tin the leads and stab them into the end of the rope light. At the place where they connect to the SSR they can be landed into the screw terminals, or in my case Molex pins were crimped and soldered on. Add one power wire all the way back to the terminal strip for the SSR and move down 4 to just after the 8th cane.

Repeat the process for the 4 cane hot leads and tap off the power wire to the first SSR. Move down four canes, but this time run a new power wire. To break it up into bundles of eight I cut the power wire and neutral just after the 2nd SSR and added a 2 pin Molex connector. The same thing just after SSR 4 and add a 4 pin Molex. Then cut all 4 just after the last cane and add another 4 pin Molex. One more 4 pin Molex at the terminal strip and power source. The SSRs are placed in a Pod made from PVC pipe and end caps wire tied to a stake. It’s a very neat design that can be easily maintained and repaired. Everything bundled up in a single cable. Now all I have to do is get the other 14 Candy Canes converted over to Ropelight….

The difference in cost to wire my Mega Tree cables was offset by the mere fact that I decided to add Molex connectors to them. I believe I saved at least 50% had I not added all the bells and whistles. I cannot claim a savings on the design of the Candy Canes either as the wire used was scrap that I recovered from a dumpster. However, this method will save you money, and will make the Annual set-up and take-down easier.

Talk:Shared Neutral Cables

2008-02-06T01:29:14Z

Jeffmill:

Some recommendations for your article...
I am not an electrician and I do not understand some of the terms you are using such THHN and SPT. Also, a picture is worth a thousand words when describing something I would love to see a picture of what it is you are describing because my mental imager is getting a little old and rusty.

(My response)
Thank you for your suggestions. This was originally written as a post in the power and electric forum. Then it was re-written for the Wiki by Matt, with the intent that I would edit it and add pictures. Illness, workload, beta testing LOR II and the 2007 display stole my attention and caused this entire article to become orphaned. For this I appologize. I have taken a copy of the wiki, and intend to make the additions you suggest and add some pictures.

My entire display is made up from these types of cables. I have a few in development, so they will work as good subjects for the pictures. (Jeff)

Talk:Shared Neutral Cables

2008-02-06T01:28:44Z

Jeffmill:

Some recommendations for your article...
I am not an electrician and I do not understand some of the terms you are using such THHN and SPT. Also, a picture is worth a thousand words when describing something I would love to see a picture of what it is you are describing because my mental imager is getting a little old and rusty.

Thank you for your suggestions. This was originally written as a post in the power and electric forum. Then it was re-written for the Wiki by Matt, with the intent that I would edit it and add pictures. Illness, workload, beta testing LOR II and the 2007 display stole my attention and caused this entire article to become orphaned. For this I appologize. I have taken a copy of the wiki, and intend to make the additions you suggest and add some pictures.

My entire display is made up from these types of cables. I have a few in development, so they will work as good subjects for the pictures. (Jeff)

Ren-T Assembly Instructions

2007-09-12T01:44:46Z

Jeffmill: /* '''BOM''' */

=='''Configurations'''==

This board can be assembled and used in various ways. It can be used simply to generate a zero-crossing signal for the Renard8, Renard64 and Ren-C boards (and optionally for some of the other boards), power for the Renard8 board, and/or convert RS232 to RS485 for use with any of the Renard coop boards (including Ren-C). It can also be built using a number of different transformers (depending on which board is used, and which transformers the builder has on hand).

=='''Selecting a Transformer'''==

There are several different possible choices of a transformer. The most basic considerations are the input voltage, the output voltage and output current ratings of the transformer. In this discussion, primary will refer to the transformers input winding(s) (that are connected to the AC power line), and secondary refers to the output winding(s) of the transformer.

The input voltage of the transformer must be the same as the AC line voltage available in your locale. You cannot use a 120VAC transformer in a location with 240 VAC power, nor can you use a 240VAC transformer if your local power is 120VAC. There are some transformers with dual primaries that can be wired up to accept either 120 or 240 VAC, but discussion of how to use these is beyond the scope of this page.

The preferred design uses a center-tapped transformer. This is a transformer which has a single output winding with three connections (one at either end of the winding, and one in the exact middle), in which the middle connection (the center-tap) is to be used. One disadvantage of this circuit is that the iron and copper in the transformer is only used with 50% effectiveness because at any point in time only half of the transformer is supplying current.

The transformer output voltage should be either 12.6VAC or 16 VAC, and the output wires from the transformer should be connected as shown here.

[[IMAGE:Xformer_conn2.gif]]

The effective schematic (taking into account the parts which are actually installed) is here:

[[IMAGE:Xformer_ct.gif]]

The waveform across the output of the transformer (pins 5,8) is a sine wave with amplitude 1.41*Vtrans when fully loaded (where Vtrans would be the 12.6V or 16V rated value of the transformer). The amplitude will be somewhat higher if there is no load on the transformer or just a minimal load. The voltage between the transformer center-tap and either of the other two legs is 1/2 of this value.

[[IMAGE:sinewave_nolabel.gif]]

The output of the rectifier circuit (VOUT+ - VOUT-) is a rectified sinewave, as shown below. The amplitude of the output waveform is (1.41*Vtrans/2 - Vf), where Vf is the forward voltage of the diodes (about 0.7V for regular diodes, 0.4V for Schottky diodes).

[[IMAGE:sinewave_rect.gif]]

=='''Assembly'''==

[[Image:Ren-T parts designation.jpg|350 px]]

===Case 1===
'''''Connecting PC to first controller without converting to RS485'''''

::* D1, D2, D3, R1, R2, P1, JR1, J1 (shunt), J2 (shunt)

===Case 2===
'''''Connecting one Controller to the next (RS485 pass-through) '''''

::* D1, D2, D3, R1, R2, JR1, JR2 (omit shunts)

===Case 3===
'''''Connecting PC to first controller, converting to RS485 in the process '''''

::*D1, D2, D3, D4, D7, R1, R2, P1, JR1, U1, U2, U3, C1, C2 (omit shunts)

=='''BOM'''==

Mouser part#'s listed.

*'''U3''' ~ 1 - 595-UA78L05ACLPRE3 - Standard 5V, 100mA Fixed Pos Voltage Regulator

*'''U2''' ~ 1 - 837-ISL81487EIP - RS-485/422 Interface ICs 5V TXRX ESD

*'''U1''' ~ 1 - 595-SN75C189AN - RS-232 Interface ICs Quad Low Pwr

*'''C1''' ~ 1 - 140-XRL16V10-RC - Radial Electrolytic Capacitors 16V 10uF 20%

*'''C2''' ~ 1 - 140-XRL16V470-RC - Radial Electrolytic Capacitors 10V 470uF 20%

*'''D1, D2, D4, D7''' ~ 4* - 625-1N5819-E3 - Schottky Rectifiers Vr/40V Io/1A

*'''D3''' ~ 1 - 604-WP7104GT ***('''''or''''')*** 604-WP7104IT - LED > GT = Green ~ IT = Red

*'''R1''' ~ 1 - 291-1K-RC - 1/4W 5% Carbon Film Resistors 1Kohms 0.05

*'''R2''' ~ 1 - 291-750-RC - 1/4W 5% Carbon Film Resistors 750ohms 0.05 (LED resistor)

*'''J1, J2''' ~ 2 - 538-22-03-2021 - .100 K.K. Connectors VERT PCB HDR 2P TIN PLATING

*2 - 649-65474-002LF - Bergcon Connectors SHUNT TIN

*'''P1''' ~ 1 - 152-3409 - D-Sub Connectors 9C R/A PCB RECPT

*'''JR1, JR2''' ~ 2 - 571-5520251-4 - Modular Jacks 8/8 SIDE ENTRY

'''''Optional Parts'''''

*1 - 693-CMF1.1111.12 - Power Entry Modules 2.5A C8 INLET PCB MT (requires the AC cord below, or an older style 'laptop' power cord. Check the data sheet for a picture.)

*1- 173-21114-E - AC Power Cord 10' 2W 18AWG BK

*1 - 571-3902613 - IC Sockets 14P ECONOMY TIN

*1 - 571-3902612 - IC Sockets 8P ECONOMY TIN

'''''TRANFORMER CHOICES'''''

41PG300 - 12.6CT .3A

*The transformers listed are not the only ones that can be used. They are what was used during the design and testing and are direct fits for the pads of the PCB.

=='''Schematic'''==
[[Image:Ren-T schematic.gif]]

=='''History'''==

2007/09/03 Removed references to non-center-tapped transformer, as they do not always reliably provide a good zero-crossing signal.

Shared Neutral Cables

2007-08-03T10:24:13Z

Jeffmill: /* Introduction */

'''This is a work in progress, please do not edit until links have been posted on the main page! Thank you.'''
==Introduction==
One way to save money and setup time on your display is to have the neutral line shared among several channels. As jeffmill has shown, however, there are many considerations that come into play to keep your display safe when using them. He also tells about some of his uses of Shared Neutral Cables in his display.

'''Here we also need to add some basic introductions (and maybe a pic) about what shared neutrals are in the first place...'''

===Disclaimers===
All the standard [[Disclaimers]] apply. If you have any questions about the use of electrical wiring and its construction you should consult a qualified electrical professional who is licensed and bonded who is knowledgeable of the electrical codes in your area. The information that follows is not to be considered a guide, but rather a discussion about the safe use of multiple circuit cables for the connection of temporary seasonal lighting. You are solely responsible for any use of this information. DoItYourselfChristmas (Hereafter known as DIYC) and its members take no responsibility for any damage or harm that may occur from using the information found herein.

==Safety Considerations==
There is no reason whatsoever to fear using a single neutral along with several strands of a smaller gauge wire as the hots, as long as a few safety precautions are followed.

===Using SPT Outdoors===
The use of SPT outdoors is a long standing debate with folks setting on both sides of the fence. Regardless of what the concerns are, the only issue here is the lack of UV protection on the wire. If you toss an indoor rated extension cord (zip cord, SPT) out in the sunlight it will eventually break down the insulation and short the conductors. No more, no less. Every one of my cables is wrapped in UV protected 3/4" black electrical tape.

I think using SPT and/or THHN is acceptable and safe to use in these cables. The indoor/outdoor status becomes a non issue when you alleviate the UV problem with UV protection. 'nuff said.

===Wire Gauge===
The neutral line should be of sufficient gauge for the total load of every circuit in the cable shared by that neutral. You must know the gauge and capacity of the wire you use for the hots, and multiply that by the number of conductors you will use in your neutral to determine the gauge of it. It is a common practice to design an 80% loading into every aspect of electrical wiring in a home - that gives you a 20% buffer as a safety margin.

Take into consideration any future additions you are planning. It may be less costly to build for a larger capacity, as smaller gauge wire can be more expensive if it is not a commonly stocked item. Also, keep in mind that SPT I or SPT II is not an indication of the capacity of the wire, it only describes the amount of insulation between the wires.

===Multi-Conductor Wire Capacity===
The NEC provides a reduction in the overall current carrying capacity of conductors in a multi-conductor cable such as this there is a mutual inductance, or interaction between the conductors that reduces their load carrying capacity. I believe that the 80% safety margin is sufficient to allow for this issue. Interpret it this way: If you have a conductor that is rated for 10 amps, design your construction so that it will carry 8 amps maximum.

===Cable Quality===
Ensure quality when constructing the cables. It is my personal opinion that they should be constructed by carefully soldering the connections. I also use heat-shrink tubing for its insulating qualities, along with the neatness of the connection which might otherwise become a big bulky wart in the cable where solder joints are located. I always do the neutral connection first, and then try to offset the position of the hots enough so they don't add to the bulk of the neutral connection. These cables will be used over and over again, year after year. Taking the time to construct them well will pay off in the end.

===Cable Length===
Ensure that you have enough length to prevent them from being tripped over, or pulled.

===GFCI===
If you don't use GFCI, you will probably lose a fuse or a Triac that thinks it’s a fuse. GFCI is a very simple differential protection scheme. It monitors the flow of current to and from a load (load = lights) If the current flowing to the load does not equal the flow back from the load down to a very minute quantity, it trips open at a very high speed.

Dropping a set of lights into a bucket of water that does not have a path to ground or some other return path to the source will not trip a GFCI. That is because the current it monitors will still be equal, and not considered a differential fault. In a ground fault, some of the current flowing to the load bypasses its normal path back from the load and travels through the ground instead. That results in an unequal measurement in the scheme = TRIP! Design cables so you can keep the connections off the ground, where rain water can flow through them and drip away. This will prevent ground faults that will trip GFCI.

GFCIs do not only trip for ground faults. It can occur when the current leaks over to another circuit and finds a return path that is not its normal course. You can prevent this in a multi-conductor scheme by ensuring quality in your construction, and also by keeping all the conductors in the cable on a single GFCI.

===Foreign Power===
====Voltage====
The use of my design of cable is solely for US power systems. I have no experience in foreign power systems. There are other folks that will surely be able to help the 220V users. When powering one of these cables with a common neutral always ensure that you are on a single hot leg of your electrical service in a given cable. This will prevent the possibility of 220Vac if the neutral becomes unbonded anywhere.

====Split Controllers====
Some of the controller manufacturers design their products to be used in Europe, the UK and Australia, and that some of the controllers are divided down the middle and can have 2 opposing legs of 120Vac powering each side, rather than using 220VAC. That is not an unsafe practice. Some may say this is not nessecary because the boards were designed for it, and 220Vac is the standard in foreign applications. However, when given the choice, it is always a good idea to choose the safer option.

==Cable Construction==
This is an example of how shared neutrals can be used in your display.
===Mega Tree===
My first cable is directly based on the design of a control cable used in the electrical industry. I chose the number of slices for my Mega Tree based on the design of this cable. It utilizes three sets of 4 #16 conductors (or two strands of SPT) with a single #12 THHN common neutral for each set. Altogether there are 15 conductors to handle the work of 24. At one end of a 40' cable there are 12 Dollar Store three-outlet extension cords, spray painted with Krylon Fusion to UV protect them. At the other end there is a set of 15 pin Molex connectors with 12 strands of #14 THHN and 3 of #12, approximately 3' long. I connect the 3' piece and female connector to the controllers. It makes for a quick connection to the tree. There are 5 of these cables to light 60 channels. 12 slices each of Red, Green, Yellow, Blue and Clear minis. Each slice of colored lights is 150 count, and the clear are 200 count.

===SSR Connections===
The second cable is a little more complicated. It combines the AC power to remotely located SSRs, along with the wire connected to the output channels to power my rope light candy canes. Once again I used Molex connectors, this time not only for the end but also to connect the SSRs to the circuit. It is a very quick way to snap in/out SSRs from the scheme even though I haven't had any failures that required this.

===Candy canes===
I calculated the total load of all the rope light combined in my canes and ran a single strand of THHN of sufficient gauge from a terminal strip at the power source. This runs all the way out to the corner and across the front of my yard. Then I marked the strand to evenly space 24 canes which came out to a little over 2' per division.

I cut 24 pieces of heat shrink about 1 1/2" each and slid them onto the wire about a foot down from the end. I stripped the very end off about 3/4" and soldered the 2' neutral for the first cane to it. Heat shrink and move everything over a couple feet. Strip 3/4" off the next mark, solder the next neutral, heat shrink and move on. 24 times and the basic cane locations are in place along with a 2' pigtail for each neutral.

Next I located an SSR just after the fourth cane. Measure out four pieces of wire to power canes 1, 2, 3 and 4. Cut them to length and begin to wrap them with 1/2" electrical tape. Leave enough conductor to tin the leads and stab them into the end of the rope light. At the place where they connect to the SSR they can be landed into the screw terminals, or in my case Molex pins were crimped and soldered on. Add one power wire all the way back to the terminal strip for the SSR and move down 4 to just after the 8th cane.

Repeat the process for the 4 cane hot leads and tap off the power wire to the first SSR. Move down four canes, but this time run a new power wire. To break it up into bundles of eight I cut the power wire and neutral just after the 2nd SSR and added a 2 pin Molex connector. The same thing just after SSR 4 and add a 4 pin Molex. Then cut all 4 just after the last cane and add another 4 pin Molex. One more 4 pin Molex at the terminal strip and power source. The SSRs are placed in a Pod made from PVC pipe and end caps wire tied to a stake. It’s a very neat design that can be easily maintained and repaired. Everything bundled up in a single cable. Now all I have to do is get the other 14 Candy Canes converted over to Ropelight….

The difference in cost to wire my Mega Tree cables was offset by the mere fact that I decided to add Molex connectors to them. I believe I saved at least 50% had I not added all the bells and whistles. I cannot claim a savings on the design of the Candy Canes either as the wire used was scrap that I recovered from a dumpster. However, this method will save you money, and will make the Annual set-up and take-down easier.