TBrownTX
Active Member
Plenty of people out there with this setup, have not seen any real-world issues as a result.
I assume the codes have a fair amount of safety margin built in for all kinds of contingencies.
Tim
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Anyone use this Romex 6/3 cable during install?
- Thread starter Dugdale
- Start date
Plenty of people out there with this setup, have not seen any real-world issues as a result.
I assume the codes have a fair amount of safety margin built in for all kinds of contingencies.
Tim
ChrisMPK
Member
Need advice. So looks like I have 300amp service. 200amp outside is for ACs, kitchen and other high amps. 100 sub panel inside garage is for indoor lights and outlets. Total of 10 15amp gfci breakers. I am installing 14-50 on 50 amp with 6/3 wire. Is it ok to install on the 100 sub panel or should be on 200.
Thanks!
Thanks!
Attachments
Great pics. Your 100 amp panel in the garage is very lightly loaded. No problem hanging a 50A 240V breaker off that.
Thank you very much! Will add the 50a on the 100amp panel. Maybe later add one more 60amp for wall charger too when we get the CT.
OK, at *that* point, you'll be close to overloading the panel since the 14-50 and the Wall Charger could both be drawing power at the same time for extended periods of time. But, if you swapped out the 14-50 for a Wall Charger at that time, then you can connect both Wall Chargers together using a data cable and tell them the maximum combined draw they can do (about 70 amps, combined). That's one of the really cool features of Tesla's wall charger.
I was thinking put the 60amp wall charger or one more 50amp 14-50 on the 200 amp later on since I won’t be cooking or using the pool at night(charger time). Should be only one AC during the summer. So I should be ok with that panel as well. Sorry I was not clear about it. But your point is taken, that would be a cool and neat setup just cost a lot more
Some AHJs aren’t super happy with “should be ok” design.I was thinking put the 60amp wall charger or one more 50amp 14-50 on the 200 amp later on since I won’t be cooking or using the pool at night(charger time). Should be only one AC during the summer. So I should be ok with that panel as well. Sorry I was not clear about it. But your point is taken, that would be a cool and neat setup just cost a lot more
I wish Tesla had a current sensor that could be placed on the main (or wherever appropriate for a situation) that would communicate via wifi to the WCs and throttle as necessary. So if my 200A feed exceeded 160a (does 80% apply here?) it would reduce the car charging.
Same way it handles it with two WCs? Once configured, no decent connection, it doesn't charge (or doesn't charge at full speed, not sure which is current behavior). The current WCs technically have the same risk.
Plus, ultimately it's protected by the main breaker.
Agree it would be difficult to get anyone to agree it's compliant. The DCC device already exists that will cut the chargers. If that could be combined with communication to throttle first that would be nice as well.
TBrownTX
Active Member
Well most other electrical cable in your home including the circuits running your dryer, oven, and AC all all run w/ Romex, so don’t see why that would be an issue.
Tim
EVer Hopeful
Active Member
It's not the temp rating, but that the wire you have has a temp rating and when you choose that wire it has a max ampacity
Check it out in the ampacity charts
Check it out in the ampacity charts
@Jschoef Yeah, it might help to look at a chart, to see how this works a little easier:
Cerrowire Resources - Ampacity Charts
Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.
www.cerrowire.com
The wire type is specified for a certain temperature, but then that determines what maximum amps it is rated for per wire gauge. So if using Romex, look in that table, and it's the first column (Romex is known as NM-B). When you look at the line for 4 gauge, it says that is rated for up to 70A. So a 60A circuit can use that. But if you look at the line above, for 6 gauge Romex, that is only allowed up to 55A, so a 60A circuit can't use that.
This post is to share my experience installing a Gen 3 Wall Connector using MC 6/2 cable in the United States.
My install officially passed inspection yesterday. Though don't read too much into that; the inspection was rather superficial. I trust this forum to provide "constructive feedback" if they see anything concerning in this post.
DISCLAIMER: I am not an electrician, but I am permitted in my state to perform electrical work on a property which I both OWN and OCCUPY. I have previously worked with old BX cable, installed a transfer switch, added multiple new circuits, and extended multiple circuits. Though this is my first time working with wire larger than 12 gauge.
I hired a professional a few years ago to add a full 200 amp load center as a subpanel powered with feed through lugs from my overfull main 200 amp panel. Part of my reason for going so big was thinking that eventually I would want to add EVSE circuits. Since I have that almost empty 200 amp subpanel in my garage, adding this EVSE circuit was electrically simple.
In my opinion, figuring out which cable to use was the easy part. Page 5 of the Tesla Gen 3 Wall Connector Manual states: "If installing for maximum power, use minimum 6 AWG, 90 degree C-rated copper wire for conductors." As previously discussed in this thread, BOTH the "6 AWG" and the "90 degree C rating" are important. I wanted to pull my wire above the drywall ceiling in my garage, which is also under the floor of my master bedroom. Since I was pulling new wire anyway, I wanted to install for maximum power. So based on previous recommendations in this thread, I ended up purchasing 50' of MC cable from Wire and Cable Your Way.
Specifically I ordered: 6/2 Copper MC Cable w/ Ground
Full description:
If you enjoy cutting MC cable, keep using whatever technique you are already using. Otherwise, if you are installing the 6/2 cable that I used, definitely budget for a "Greenlee 0952-01 Quick Load Clamp Cable Cutter" (Amazon), or a more expensive equivalent. Once you adjust it with some test cuts, the basic technique is put the cable in the tool slot, pull the cable till it locks, turn the handle until the handle spins freely. Next remove the cable from the cutter, then grab the discard end with your favorite adjustable pliers and twist. After a few practice cuts you will easily strip the MC cable without damaging the insulation on the conductors. Besides saving time and cursing, the main advantage is that you can easily make repeated cuts without nicking the conductor insulation which increases safety.
Note: Wire and Cable Your Way did not include any red plastic anti-shorts. Technically I'm not sure anti-short bushings are required with MC. However, I wanted to protect my conductors. I ended up buying a package of 3/4" flex anti-short bushings at Home Depot. They turned out to be a bit too long, but with a little scissor trimming they did barely fit, and still made a full circle inside the MC. I don't know if trimming is to code. I am however confident the insulation on my conductors is well protected by what I did. It would obviously be much better if you could find anti-short bushings that actually fit without trimming.
The cable I ordered came with three wires, black, white, and green. So I picked up a roll of RED electrical tape at Home Depot. I wrapped the white wire with red tape before it went into the breaker, and before it went into the L2/N terminal block. That way the next electrician who looks at the marked white wire will instantly know it is being used as HOT not Neutral.
It was surprisingly difficult for me to find a connector rated for 0.755 inch aluminum MC cable. I found lots of Flexible Conduit connectors, but though they look very similar code does not automatically allow using them with MC cable. Eventually I found the "Arlington 8402 Cable Connector, AC/MC,3/4",Two Screw,Zinc Die Cast." I verified in the Arlington catalog that 0.755 inches was within the 8402's 0.525 - 0.780 cable size range. The table in the catalog also showed that the 8402 was rated for MC Aluminum Corrugated and MC Aluminum Contiguous Corrugated, as well as for options I knew I had not ordered including MC Steel, Armored Cable, and Flexible Metal Conduit. I used one connector for rear entry into the Wall Connector, and one at the load center.
I purchased my connectors through Rexelusa.com expecting to pick the order up locally, but they shipped it, and charged me nominal shipping. I did have to register to use their site. However, I listed my company as "Home Owner" and was quickly approved, unlike some other electrical supply houses. I have only used Rexel for that one order, so your mileage may vary.
Note: Both the cable and the 4802 connector I ordered are for DRY locations.
Some of you may also be interested in transitioning from MC to 3/4 inch EMT. Especially if you are feeding from the top or the bottom of the wall connector, and want to use a smooth EMT compression fitting for the final connection to the wall connector so the charging cable does not rub against rough objects like screws. An Arlington catalog explicitly showed screwing the 4802 connector into an "Arlington 2411 Zinc Combination Coupling; Fits 3/4 inch EMT - 3/4 inch F. Thread" to make that transition. I ordered one, and they do screw together. Thankfully, I did not end up needing to transition to EMT.
I was very fortunate that I was mounting my wall connector on a fairly deep box/wall that I had previously attached to my concrete garage wall when I installed a central vacumn and associated electrical outlets. It was tight, but the MC cable was just barely able to bend enough inside the deep box that I could feed the Wall Connector from the rear. Thus I did not need to transition to EMT to make a sharper bend, or to top feed the Wall Connector. I don't think the MC would have made the bend in a 2x4 stud wall, it MIGHT just barely in a 2x6 wall. but I think it would probably be fine in a 2x8 stud wall.
Ultimately, materials wise my install was very simple. The Gen 3 Wall Connector, an Arlington 4802 Cable Connector, an anti-short bushing, the 6/2 MC cable, another anti-short bushing, another Arlington 4802, and a simple 60 amp breaker that matched my load center. Supplemented with red tape to mark the white wire as hot, and some straps to secure the MC cable near the Load Center and Wall Connector. Straps are not required where I fished the cable through my ceiling.
I already owned most of the tools specified on page 12 of the Tesla installation manual. I purchased a torque screwdriver, aka torq driver, needed for tightening the wire connectors to the correct torque at the Wall Connector, the breaker, and the ground bar. The Wall Connector wants 50 pound-inches of torque, my breaker and ground bar specified twenty something pound-inches of torque (your breaker and ground bar may be different). I purchased a larger wire stripper capable of handling 6 awg and 8 awg stranded copper (the conductors are 6 awg, the ground is 8 awg). It is possible to strip wire without a wire stripper, and I initially planned to, but then I chickened out. The step bit specified was a bit pricy, but seemed required for rear entry. I'm very glad I also purchased a Greenlee 0952-01 cutter since I was using MC. I had to purchase a big auger bit to run the cable through a beam in the middle of my garage ceiling. I also purchased a fixed blade utility knife and a 50 pack of drywall blades for making holes in my ceiling. I already owned pull tape, fish rods, a big bolt cutter, a good wire cutter, wrenches, multi-screwdrivers, drill bits, multiple hand-drills, and (optional) a drill press.
Some suggestions (some gleaned from YouTube, some from personal mistakes):
If you don't feel totally confident working with electricity, but want to put some sweat equity in the job, then follow my rule "Do not hire an electrician to do carpentry or drywall." In this context that means pull the MC cable yourself from your load center to where the charger is going, if necessary construct a place to mount the wall connector, and plan on repairing the holes you make yourself. Just hire an electrician to make the final connections at both ends, perhaps on an hourly basis.
My original load center is installed on a scrap of oriented strand board, which is mounted to two by fours attached to my garage's concrete walls. When I wanted a subpanel installed a few feet from my load center, I knew the electrician would need a similar setup to mount the subpanel. So I mounted pressure treated two by fours to the concrete wall. Then I mounted a sheet of plywood on the two by fours. I took me quite a few hours. I cursed some broken concrete drill bits, and had to go buy more. I probably overbuilt it, and I definitely built it for future expansion. However, when the electrician came to bid the subpanel installation he didn't have to charge me electrician rates for guessing how long it would take to drill holes in concrete.
Pulling cable is a miserable job full of uncertainties. In my case it required cutting multiple holes in the drywall ceiling, a bit of rerouting from my initial plan, and of course patching all those holes. My job only involved pulling cable from one side of a two car garage to the other side. I only used 36 feet of my 50 foot spool. Yet, it took me way more than eight hours just to pull the cable! No sane electrician is going to bid that job for less than thousands of dollars. However, just connecting the wires at both ends has almost no uncertainty, and most electricians could practically do that job in their sleep.
Good luck on your own project. Whether you do it yourself, hire some of it out, or hire it all out. At the end of the day I'm generally happy that I went Wall Connector, and totally happy that I went MC 6/2. Though I do wonder if I should have installed a J1772 charger and purchased a spare J1772 to Tesla adapter instead for future flexibility.
My install officially passed inspection yesterday. Though don't read too much into that; the inspection was rather superficial. I trust this forum to provide "constructive feedback" if they see anything concerning in this post.
DISCLAIMER: I am not an electrician, but I am permitted in my state to perform electrical work on a property which I both OWN and OCCUPY. I have previously worked with old BX cable, installed a transfer switch, added multiple new circuits, and extended multiple circuits. Though this is my first time working with wire larger than 12 gauge.
I hired a professional a few years ago to add a full 200 amp load center as a subpanel powered with feed through lugs from my overfull main 200 amp panel. Part of my reason for going so big was thinking that eventually I would want to add EVSE circuits. Since I have that almost empty 200 amp subpanel in my garage, adding this EVSE circuit was electrically simple.
In my opinion, figuring out which cable to use was the easy part. Page 5 of the Tesla Gen 3 Wall Connector Manual states: "If installing for maximum power, use minimum 6 AWG, 90 degree C-rated copper wire for conductors." As previously discussed in this thread, BOTH the "6 AWG" and the "90 degree C rating" are important. I wanted to pull my wire above the drywall ceiling in my garage, which is also under the floor of my master bedroom. Since I was pulling new wire anyway, I wanted to install for maximum power. So based on previous recommendations in this thread, I ended up purchasing 50' of MC cable from Wire and Cable Your Way.
Specifically I ordered: 6/2 Copper MC Cable w/ Ground
Full description:
- 6-2C Metal Clad (MC) Cable with Ground, Aluminum Armored, Stranded Copper Conductors
- Size 6 AWG
- Outside Diameter: 0.755 inches
- Ampere Rating THHN: 75 @ 90 degree C.
If you enjoy cutting MC cable, keep using whatever technique you are already using. Otherwise, if you are installing the 6/2 cable that I used, definitely budget for a "Greenlee 0952-01 Quick Load Clamp Cable Cutter" (Amazon), or a more expensive equivalent. Once you adjust it with some test cuts, the basic technique is put the cable in the tool slot, pull the cable till it locks, turn the handle until the handle spins freely. Next remove the cable from the cutter, then grab the discard end with your favorite adjustable pliers and twist. After a few practice cuts you will easily strip the MC cable without damaging the insulation on the conductors. Besides saving time and cursing, the main advantage is that you can easily make repeated cuts without nicking the conductor insulation which increases safety.
Note: Wire and Cable Your Way did not include any red plastic anti-shorts. Technically I'm not sure anti-short bushings are required with MC. However, I wanted to protect my conductors. I ended up buying a package of 3/4" flex anti-short bushings at Home Depot. They turned out to be a bit too long, but with a little scissor trimming they did barely fit, and still made a full circle inside the MC. I don't know if trimming is to code. I am however confident the insulation on my conductors is well protected by what I did. It would obviously be much better if you could find anti-short bushings that actually fit without trimming.
The cable I ordered came with three wires, black, white, and green. So I picked up a roll of RED electrical tape at Home Depot. I wrapped the white wire with red tape before it went into the breaker, and before it went into the L2/N terminal block. That way the next electrician who looks at the marked white wire will instantly know it is being used as HOT not Neutral.
It was surprisingly difficult for me to find a connector rated for 0.755 inch aluminum MC cable. I found lots of Flexible Conduit connectors, but though they look very similar code does not automatically allow using them with MC cable. Eventually I found the "Arlington 8402 Cable Connector, AC/MC,3/4",Two Screw,Zinc Die Cast." I verified in the Arlington catalog that 0.755 inches was within the 8402's 0.525 - 0.780 cable size range. The table in the catalog also showed that the 8402 was rated for MC Aluminum Corrugated and MC Aluminum Contiguous Corrugated, as well as for options I knew I had not ordered including MC Steel, Armored Cable, and Flexible Metal Conduit. I used one connector for rear entry into the Wall Connector, and one at the load center.
I purchased my connectors through Rexelusa.com expecting to pick the order up locally, but they shipped it, and charged me nominal shipping. I did have to register to use their site. However, I listed my company as "Home Owner" and was quickly approved, unlike some other electrical supply houses. I have only used Rexel for that one order, so your mileage may vary.
Note: Both the cable and the 4802 connector I ordered are for DRY locations.
Some of you may also be interested in transitioning from MC to 3/4 inch EMT. Especially if you are feeding from the top or the bottom of the wall connector, and want to use a smooth EMT compression fitting for the final connection to the wall connector so the charging cable does not rub against rough objects like screws. An Arlington catalog explicitly showed screwing the 4802 connector into an "Arlington 2411 Zinc Combination Coupling; Fits 3/4 inch EMT - 3/4 inch F. Thread" to make that transition. I ordered one, and they do screw together. Thankfully, I did not end up needing to transition to EMT.
I was very fortunate that I was mounting my wall connector on a fairly deep box/wall that I had previously attached to my concrete garage wall when I installed a central vacumn and associated electrical outlets. It was tight, but the MC cable was just barely able to bend enough inside the deep box that I could feed the Wall Connector from the rear. Thus I did not need to transition to EMT to make a sharper bend, or to top feed the Wall Connector. I don't think the MC would have made the bend in a 2x4 stud wall, it MIGHT just barely in a 2x6 wall. but I think it would probably be fine in a 2x8 stud wall.
Ultimately, materials wise my install was very simple. The Gen 3 Wall Connector, an Arlington 4802 Cable Connector, an anti-short bushing, the 6/2 MC cable, another anti-short bushing, another Arlington 4802, and a simple 60 amp breaker that matched my load center. Supplemented with red tape to mark the white wire as hot, and some straps to secure the MC cable near the Load Center and Wall Connector. Straps are not required where I fished the cable through my ceiling.
I already owned most of the tools specified on page 12 of the Tesla installation manual. I purchased a torque screwdriver, aka torq driver, needed for tightening the wire connectors to the correct torque at the Wall Connector, the breaker, and the ground bar. The Wall Connector wants 50 pound-inches of torque, my breaker and ground bar specified twenty something pound-inches of torque (your breaker and ground bar may be different). I purchased a larger wire stripper capable of handling 6 awg and 8 awg stranded copper (the conductors are 6 awg, the ground is 8 awg). It is possible to strip wire without a wire stripper, and I initially planned to, but then I chickened out. The step bit specified was a bit pricy, but seemed required for rear entry. I'm very glad I also purchased a Greenlee 0952-01 cutter since I was using MC. I had to purchase a big auger bit to run the cable through a beam in the middle of my garage ceiling. I also purchased a fixed blade utility knife and a 50 pack of drywall blades for making holes in my ceiling. I already owned pull tape, fish rods, a big bolt cutter, a good wire cutter, wrenches, multi-screwdrivers, drill bits, multiple hand-drills, and (optional) a drill press.
Some suggestions (some gleaned from YouTube, some from personal mistakes):
- Read the Tesla installation manual at least twice.
- Get your conduit or MC cable connector location finalized before drilling pilot holes in the wall or the holes in the Wall Connector Wirebox. Then drill the Wirebox. Finally drill the pilot holes in the wall. Adjusting holes in the wall a fraction of an inch in any direction is easy. Adjusting the connector location is not always so easy. Tesla sells a replacement Wall Connector Wirebox Kit if you need to "adjust" something you did to the Wirebox.
- Thread the zip tie through the hole in the Wirebox before installing the wires. Then zip it after the wires are torqued down.
- Remember that the Wirebox and your breaker will both have strip gauges showing how much to strip the wire, and will also indicate how much torque they need (probably pound-INCHES). Not using ENOUGH torque is a common cause of fires. Using TOO MUCH torque can damage the connection. If you confuse pound-inches with pound-feet of torque you will break something.
- A Square Drive screwdriver is best for tightening most electrical screws these days. The Tesla Wirebox is an exception, and Tesla provides their own 4mm hex bit.
- Remember that the breaker and the ground bar in your load center might need different lengths of wire from the connector into the box. (Yes, I ended up installing a new ground bar in my subpanel.)
- and if you are using EMT
If you don't feel totally confident working with electricity, but want to put some sweat equity in the job, then follow my rule "Do not hire an electrician to do carpentry or drywall." In this context that means pull the MC cable yourself from your load center to where the charger is going, if necessary construct a place to mount the wall connector, and plan on repairing the holes you make yourself. Just hire an electrician to make the final connections at both ends, perhaps on an hourly basis.
My original load center is installed on a scrap of oriented strand board, which is mounted to two by fours attached to my garage's concrete walls. When I wanted a subpanel installed a few feet from my load center, I knew the electrician would need a similar setup to mount the subpanel. So I mounted pressure treated two by fours to the concrete wall. Then I mounted a sheet of plywood on the two by fours. I took me quite a few hours. I cursed some broken concrete drill bits, and had to go buy more. I probably overbuilt it, and I definitely built it for future expansion. However, when the electrician came to bid the subpanel installation he didn't have to charge me electrician rates for guessing how long it would take to drill holes in concrete.
Pulling cable is a miserable job full of uncertainties. In my case it required cutting multiple holes in the drywall ceiling, a bit of rerouting from my initial plan, and of course patching all those holes. My job only involved pulling cable from one side of a two car garage to the other side. I only used 36 feet of my 50 foot spool. Yet, it took me way more than eight hours just to pull the cable! No sane electrician is going to bid that job for less than thousands of dollars. However, just connecting the wires at both ends has almost no uncertainty, and most electricians could practically do that job in their sleep.
Good luck on your own project. Whether you do it yourself, hire some of it out, or hire it all out. At the end of the day I'm generally happy that I went Wall Connector, and totally happy that I went MC 6/2. Though I do wonder if I should have installed a J1772 charger and purchased a spare J1772 to Tesla adapter instead for future flexibility.
Awesome write up. I too found that finding proper connectors for 6/2 MC wasn’t easy. For cutting it, I did it the manual way of unwrapping the MC jacket from an end. Messy but works if you’re careful. As far as J1772 for future proof goes, tackle that if/when you need to.
EVer Hopeful
Active Member
...well that is the point of most DIY projects. That and buying yet more tools!
Thanks for the excellent writeup
I had forgotten, but now I vaguely remember unwrapping BX back in the 1990's before switching to a hacksaw, and then buying my first rotary cutter. In an emergency, I could probably still eventually start a fire using a cord to make a bow like they taught me in the Boy Scouts. However, I strongly prefer using a long lighter, or at least a match.
My J1772 thoughts were mainly focused on unexpected needs. Things like a non-Tesla BEV rental, a BEV visitor, or the recent rumors Tesla might switch to CCS. Assuming I keep my first Tesla as long as I plan, replacing the Wall Connector when I get the next car shouldn't happen soon or be a big issue.
Large Rotary Cutter, Torque Screwdriver, Large Wire Stripper, Fixed Blade Utility Knife, Step Bit, Auger Bit.
EVer Hopeful
Active Member
Large Rotary Cutter, Torque Screwdriver, Large Wire Stripper, Fixed Blade Utility Knife, Step Bit, Auger Bit.
I'm going to look up "Torque Screwdriver" - whoever (did or did not) installed mine (may or may not have) used a torque wrench with the supplied star bit to set the connectors properly
Similar threads
- Question
