3 wire sub panel only 2 120v outlets

[Tubecatgs]

A friend of mine has a detached garage (200 feet from the house/service panel) with a newer Square D 100 amp Homeline sub panel that was never hooked up. Running to the sub panel from the service panel are only (3) 6 gauge aluminum (Erskine I think they call it) direct burial wires. I think code states for a new installation sub panel it would require 4 wires for h/h/n/g but this is not an option.... He only wants to run a few outlets and lights (we were hoping for (2) 15 or 20 amp breakers only. Oh and he has for the main breaker to feed the sub panel a 50 amp 2 pole GFI breaker but I was concerned that this breaker only has an 8 gauge neutral wire (from the breaker to neutral bar) and the load wires to the sub panel are 6 gauge... there are also 2 ground rods to the sub panel outside the garage and the neutral is not bonded with the ground at this point. What are the possible options to safely hook up the sub panel with existing wires? (My shop only has 3 wires, no ground but does have ground rods)... and/or since he won't need any 220 lines would one option be to use just 1 hot for hot, 1 wire instead of hot use for neutral and the 3rd wire for ground? (Leaving second load terminal unused in subpanel)... thanks for your help.

 

[Megawatt]

A friend of mine has a detached garage (200 feet from the house/service panel) with a newer Square D 100 amp Homeline sub panel that was never hooked up. Running to the sub panel from the service panel are only (3) 6 gauge aluminum (Erskine I think they call it) direct burial wires. I think code states for a new installation sub panel it would require 4 wires for h/h/n/g but this is not an option.... He only wants to run a few outlets and lights (we were hoping for (2) 15 or 20 amp breakers only. Oh and he has for the main breaker to feed the sub panel a 50 amp 2 pole GFI breaker but I was concerned that this breaker only has an 8 gauge neutral wire (from the breaker to neutral bar) and the load wires to the sub panel are 6 gauge... there are also 2 ground rods to the sub panel outside the garage and the neutral is not bonded with the ground at this point. What are the possible options to safely hook up the sub panel with existing wires? (My shop only has 3 wires, no ground but does have ground rods)... and/or since he won't need any 220 lines would one option be to use just 1 hot for hot, 1 wire instead of hot use for neutral and the 3rd wire for ground? (Leaving second load terminal unused in subpanel)... thanks for your help.

You are correct on it by code should have a 4 wire service and being on a 50 amp double pole GFCI breaker is required that a building be GFCI Protected. # 6 aluminum is only good for 40 amps since the insulation is probably USE or UF cable. Take them ground rods loose you don’t need them. Even though you don’t have an equipment ground pulled to the building, your still protected by the GFCI breaker which will still work without the ground wire. The building is still not by code but it’s usable with 2 hots and 1 neutral. Yes the # 8 neutral needs to the same size as the ungrounded conductors because you cannot derate a neutral until you exceed 200 amps which is in article 250 of the 2020 NEC.

 

[Tubecatgs]

Thank you... darn. It doesn't look like you can modify the breaker to accept a larger neutral wire.. if that scenario did work, would you still bond the neutral and ground (since their is a GFI at the main panel)? Next question or option, to make sure their is a ground back to the service panel, could you use only one hot wire? Say use one of the 6 guage wires and a standard single pole (say 30 or 40 amp breaker or even one side of the GFI breaker) at the service panel to one side of the sub panel hot, use the 2nd 6 gauge wire as the ground and 3rd wire for the neutral? Making sure to only use 2 15 amp breakers on the one side of the sub panel? Thank you!

 

[Megawatt]

Thank you... darn. It doesn't look like you can modify the breaker to accept a larger neutral wire.. if that scenario did work, would you still bond the neutral and ground (since their is a GFI at the main panel)? Next question or option, to make sure their is a ground back to the service panel, could you use only one hot wire? Say use one of the 6 guage wires and a standard single pole (say 30 or 40 amp breaker or even one side of the GFI breaker) at the service panel to one side of the sub panel hot, use the 2nd 6 gauge wire as the ground and 3rd wire for the neutral? Making sure to only use 2 15 amp breakers on the one side of the sub panel? Thank you!

My friend I would go ahead and use the sub panel @ 240/120vac and hook up the neutral to the neutral bar, you probably need to add a ground bar which you can purchase at Home Depot and Lowe’s. On a sub panel you have to keep the grounds and neutrals separate. Your concern about the 4th wire or equipment ground is not that much to worry about. Remember the neutral is a GROUNDED conductor. The only real problem is how much load he puts on his building because I have seen aluminum wire get so hot it will melt all the insulation. Good luck

 

[DRIVAN]

hi in my situation, we bought a home that has detached building between main home and backyard building within 25 feet apart...both have ground rods, both have outdoor panels of their own...when buying this home from 2014, feeder line between main panel and sub panel is 3 wires..2 hots and 1 neutral...this still be debated as today, that to be safe the code requires 4 wires but in my situation, the subpanel is outdated since late 80's while main panel been updated since 2000..ITE panel is same as GE or SquareD QO breakers..just regular breakers, not fancy fault arc breakers that attach with pigtail white wire is way modern than simple setup my house has since its built 80's...but my issue was subpanel its Federal Pacific ..those are not safe since code change, but my surprise lucky no any 250v outlets ran to the panel and its only 110v outlets and light switch..it been wire unfinished, cause i notice they were 2 50A breakers not been used at all..maybe planning to run heavy usage and my guess inspection did not pass in flying colors to have wire like that when their not grounded to main panel to the subpanel...so my thinking the seller of the house did is do not attach no wiring on double pole 50a break just leave 20amps 110v breakers outlets wiring alone and make sure neutral and ground not bonded since my understanding why detached garage is on its owned foundation and has 2nd ground rod nearby the subpanel ..while neutral that feeding it is already grounded from main panel for all 110v circuit breakers when majority electronics only get complete circuit with one hot and one neutral to 60AMP main panel breaker, it will trip from their but one thing i don't understand in texas code..this is one of shortcuts that save people time and money that this is still safe for 110v without need having extra ground protection..my guess its only when planning run 240v outlet that, yes you do need extra ground wire cause 3 prong plug has no way for appliance to trip the breaker when its gonna fault to earth ground only...so 4th prong plug come in play for safety since ground and neutral are tie together for appliance that in case a fault ..it will go to ground that share with neutral on appliance same time trip 60AMP from main breaker, not the subpanel it still be closed while it turn off entire subpanel until appliance is corrected or fix to reestablish power again...this only apply to 4 wire plug...for outdoor HVAC..if my situation is only 3 wire to subpanel...its still safe when 30amp fuse disconnect switch between subpanel since fuses keep everything safe from over-current and lighting surge will be require to protect your HVAC or minisplit system i install early feb cause in texas weather its all over the map..hot and cold in matter hours and days...its unpredictable here..so tell me if i am wrong ..just tell me now that i will add 4th wire from main panel to subpanel ...a 6 gauge THHN ground wire i have plan to installed later on the week, i gonna fish tape through existing conduit since its only 60AMPS gonna from house to detached garage ..i have no plans to add anything else since main panel is only 150 AMPS..anything more ..i already max out of amperage for total main box..i have to keep of mind since detached building is only split system and light switch only running with water fountain machine ...both are 20 amps each breaker..not sure if i need too but i want to be safe for the bulding so i went ahead replace the outdated subpanel with squareD 100AMP subpanel is not fancy that similar to main panel but shorter and less spaces..i go with 6 spaces..its what i need for my application for minisplit system i mention..so i went wire exactly as last box was wire grounds go to separated ground bar and all neutrals from 110v outlets goes to neutral bar is not bonded since its already grounded to main box anyway..its why our local inspection pass is as is..since i am no electrician but i have knowledge how to wire everything together and so far ..i have not see anything go wrong in this setup the split sytem is on fuse panel while subpanel 110v is already grounded with neutral from other box while earthground is grounded with subpanel with frame and ground bus bar...so it is still safe , but for extra precaution..if 4th wire the ground line is needed ..i will add it if the code requires it to keep my house and detached safe from any nature and machinery occurrence to cause a fault ..just help me god i am right or not..you be the judge on that

 

[Megawatt]

hi in my situation, we bought a home that has detached building between main home and backyard building within 25 feet apart...both have ground rods, both have outdoor panels of their own...when buying this home from 2014, feeder line between main panel and sub panel is 3 wires..2 hots and 1 neutral...this still be debated as today, that to be safe the code requires 4 wires but in my situation, the subpanel is outdated since late 80's while main panel been updated since 2000..ITE panel is same as GE or SquareD QO breakers..just regular breakers, not fancy fault arc breakers that attach with pigtail white wire is way modern than simple setup my house has since its built 80's...but my issue was subpanel its Federal Pacific ..those are not safe since code change, but my surprise lucky no any 250v outlets ran to the panel and its only 110v outlets and light switch..it been wire unfinished, cause i notice they were 2 50A breakers not been used at all..maybe planning to run heavy usage and my guess inspection did not pass in flying colors to have wire like that when their not grounded to main panel to the subpanel...so my thinking the seller of the house did is do not attach no wiring on double pole 50a break just leave 20amps 110v breakers outlets wiring alone and make sure neutral and ground not bonded since my understanding why detached garage is on its owned foundation and has 2nd ground rod nearby the subpanel ..while neutral that feeding it is already grounded from main panel for all 110v circuit breakers when majority electronics only get complete circuit with one hot and one neutral to 60AMP main panel breaker, it will trip from their but one thing i don't understand in texas code..this is one of shortcuts that save people time and money that this is still safe for 110v without need having extra ground protection..my guess its only when planning run 240v outlet that, yes you do need extra ground wire cause 3 prong plug has no way for appliance to trip the breaker when its gonna fault to earth ground only...so 4th prong plug come in play for safety since ground and neutral are tie together for appliance that in case a fault ..it will go to ground that share with neutral on appliance same time trip 60AMP from main breaker, not the subpanel it still be closed while it turn off entire subpanel until appliance is corrected or fix to reestablish power again...this only apply to 4 wire plug...for outdoor HVAC..if my situation is only 3 wire to subpanel...its still safe when 30amp fuse disconnect switch between subpanel since fuses keep everything safe from over-current and lighting surge will be require to protect your HVAC or minisplit system i install early feb cause in texas weather its all over the map..hot and cold in matter hours and days...its unpredictable here..so tell me if i am wrong ..just tell me now that i will add 4th wire from main panel to subpanel ...a 6 gauge THHN ground wire i have plan to installed later on the week, i gonna fish tape through existing conduit since its only 60AMPS gonna from house to detached garage ..i have no plans to add anything else since main panel is only 150 AMPS..anything more ..i already max out of amperage for total main box..i have to keep of mind since detached building is only split system and light switch only running with water fountain machine ...both are 20 amps each breaker..not sure if i need too but i want to be safe for the bulding so i went ahead replace the outdated subpanel with squareD 100AMP subpanel is not fancy that similar to main panel but shorter and less spaces..i go with 6 spaces..its what i need for my application for minisplit system i mention..so i went wire exactly as last box was wire grounds go to separated ground bar and all neutrals from 110v outlets goes to neutral bar is not bonded since its already grounded to main box anyway..its why our local inspection pass is as is..since i am no electrician but i have knowledge how to wire everything together and so far ..i have not see anything go wrong in this setup the split sytem is on fuse panel while subpanel 110v is already grounded with neutral from other box while earthground is grounded with subpanel with frame and ground bus bar...so it is still safe , but for extra precaution..if 4th wire the ground line is needed ..i will add it if the code requires it to keep my house and detached safe from any nature and machinery occurrence to cause a fault ..just help me god i am right or not..you be the judge on that

Drivan yes you need 4 wires from the main panel to your sub panel and there is no way your main panel is about overloaded. You probably counted all the breakers and let me guess it exceeded 150 amps but you have 2 kinds of loads in your panel, one is your calculated load which is the math you do to size your breakers, the other is your actual load and I bet if you put an amprobe on your panel you wouldn’t be pulling 20-30 amps so you are not going to overload your panel. Your outside HVAC equipment only has 3 wires because it doesn’t require a neutral. Your buildings all have to be GFCI protected and remove your ground rods at all your sub panels, it’s not required with 4 wires feeding each panel. Good luck with your project

 

[DRIVAN]

Drivan yes you need 4 wires from the main panel to your sub panel and there is no way your main panel is about overloaded. You probably counted all the breakers and let me guess it exceeded 150 amps but you have 2 kinds of loads in your panel, one is your calculated load which is the math you do to size your breakers, the other is your actual load and I bet if you put an amprobe on your panel you wouldn’t be pulling 20-30 amps so you are not going to overload your panel. Your outside HVAC equipment only has 3 wires because it doesn’t require a neutral. Your buildings all have to be GFCI protected and remove your ground rods at all your sub panels, it’s not required with 4 wires feeding each panel. Good luck with your project

well, yes its been caculated by counting breakers..reason why main house HVAC is oversize due to age of unit that since it been replace year ago..due to fan motor keep gonna out and not able to cool the house during summer while electric heater in those units use too much amps during winter that it been replace twice during lifespan since i bought the house 2014..unit been house since late 90's..so i my guess it was over amperage and lucky so far..fuse breaker discount switch does the job well to keep house and unit safe from overage short during bad weather..so we we decided to replace entire unit from inside and outside..both been bad through out the years..since house been around since late 80's..the inside unit never been change while outside been 2nd change...guess 1st one went bad that been replace with generic one 3 ton condessor but that was POS motor that when it rain..motor fan is facing up..now days fan motors are facing down so rain won't able penetrate the fan spindle plastic nose that hold the rod..they are never water tight seal or else it won't move freely to begin with..bad design idea back then..it like the wiring to subpanel..so many versions, everyone seems agree to 2017 rule...subpanel to detached building need rod nearby plus 4th wire is the ground from main panel to the subpanel while both are earth grounded ...this what online come to conclusion to final version i hope..but in case the folks NEC decided to make another changes.. it means ...still not safe for some reason but in my opinion..nothing is safe when dealing electricity longest everything complete the path first from source to house and back to the source...electrons never like to sit still...so your saying subpanels don't need rod cause your talking about subpanel is indoor to main house ..on my situation is outside to detechaed to garage area from my backyard is 25ft between house and backyard...city call it detached garage and i called it my private suite with bed and minisplit..i have not thinking about adding plumbing yet...longest it heats and cool in that room..thats more enough for me to get started moving piece by piece to that room..my family planning hired professional electrician to upgrade the main panel from 150AMP to 200AMP fully..so in case i am not overamperage yet...not yet so far ..cause all my appliance in main house been replace with newer ones that does not over used the amps even breakers are oversize .yes ..i beleive your correct that its only 30amps for stove vs 60amps breaker in used while primary HVAC..using 60AMPS breakers while box inside the house that used electric heater for the home been replace since blower fan is not overamperage anymore while heater is not as well..so its 30amps or 40 amps..depending how long its on but during summer its easy for the load since condenser kicks in ..its only 30amps..but my surprise its lot less due to updates to refrigerant that use less power for condensing when its still new for the age 1yr old so far...but my question to that question is i been searching online if its necessary add 4th wire to panel to panel that connect each other with ground..i am planning to do so to keep up to code when subpanel is not bonded and box is grounded to ground rod..so every 110v outlets are grounded to earth while neutral that return to the source is grounded to main panel bonded neutral and grounds with its main ground rods..since the box been their since 2003...since ITE brand been bought out by Siemens since the design is all same with SquareD homeline and GE brand breakers QO breakers ..not very special for this home..they keep it simple and normal that been working since 90's and over 2000's so far...yes our home is GCFI protected in bathrooms and washer room..but stove and dryer no..its regular outlets since both are in main house ..not in detached garage back area since its only regular outlets since my surprise FPE old panel...i see many flaws in them..well hots bus part are separated between in middle from both ends..so both halves is independent to 120v leg while neutral is floating to right side on plastic bottom what its attach to...while ground bus bar is separated from anywhere in box is not touching neutral bus bar and its grounded to the box frame while thick gauge wire is attach to earth ground rod..i did examine closely and wondering why its 3 wire feeding only ...then i notice on bottom of neutral bus bar lug ..cause it comes 2 lug screws one for white wire coming from main panel..and bottom ..their was a bare wire been cut off for unknown reason..and wondering it used to be attach as jumper to ground bus bar when ground rod is next to detached building ...then also notice 2 50amp breakers on top..one for each leg but nothing is attached to them..my guess this panel from FPE did is oldschool way to get 240v...is put one breaker on each leg ..makes sense to me but nobody is doing this anymore since double pole breakers exists for this reason..they intended to be more safe than using 2 breakers same time ..its very similar to my old house i used to lived...2 hots, each feed right and left...the way they wire it...is used both breakers each side to get 240v ...very dangerous back then but the rules are the same ...bonded from main panel for neutral and ground ..and grounded to rod and water galvanized pipe faucet..., i grew up in that house for over 20 years until i moved out to bigger home like this one i am mentioning about this FPE panel that i recongize from..only difference is its the subpanel...that been bother me for awhile since i move in..the seller who sold this home went through many opinions and many contractors while county and city pass inspected many times, one thing i did notice the seller..it upset more when house title holder who holds title..is reading the documents of house history inspections and issues ...i notice this old man ..was getting frustrated with banker lawyers when we are in signing process to give title transfer the home to new home owners ..he want to rush it got me suspicious about him with whole process..why takes too much time and ask more money..on clossing date than origninal was ask for..i wish i could check or hired my owned inspectors but this man ..rush us to final day..i hope i made right decison buying this house that we like but also we gonna get 2nd opinion with newer homes that been built up to code than 1987 homes that seems still safe ....but my old house is built since 1973..that my father raise me been safe since but wiring wasn't sure back then..so just maybe its roll of the dice for everyone..

 

[Mike Johnson]

Megawatt you have more patience than me to read that lot sheesh both posts all one sentence. Arghhhhhhhhhhhhhh

 

[Megawatt]

well, yes its been caculated by counting breakers..reason why main house HVAC is oversize due to age of unit that since it been replace year ago..due to fan motor keep gonna out and not able to cool the house during summer while electric heater in those units use too much amps during winter that it been replace twice during lifespan since i bought the house 2014..unit been house since late 90's..so i my guess it was over amperage and lucky so far..fuse breaker discount switch does the job well to keep house and unit safe from overage short during bad weather..so we we decided to replace entire unit from inside and outside..both been bad through out the years..since house been around since late 80's..the inside unit never been change while outside been 2nd change...guess 1st one went bad that been replace with generic one 3 ton condessor but that was POS motor that when it rain..motor fan is facing up..now days fan motors are facing down so rain won't able penetrate the fan spindle plastic nose that hold the rod..they are never water tight seal or else it won't move freely to begin with..bad design idea back then..it like the wiring to subpanel..so many versions, everyone seems agree to 2017 rule...subpanel to detached building need rod nearby plus 4th wire is the ground from main panel to the subpanel while both are earth grounded ...this what online come to conclusion to final version i hope..but in case the folks NEC decided to make another changes.. it means ...still not safe for some reason but in my opinion..nothing is safe when dealing electricity longest everything complete the path first from source to house and back to the source...electrons never like to sit still...so your saying subpanels don't need rod cause your talking about subpanel is indoor to main house ..on my situation is outside to detechaed to garage area from my backyard is 25ft between house and backyard...city call it detached garage and i called it my private suite with bed and minisplit..i have not thinking about adding plumbing yet...longest it heats and cool in that room..thats more enough for me to get started moving piece by piece to that room..my family planning hired professional electrician to upgrade the main panel from 150AMP to 200AMP fully..so in case i am not overamperage yet...not yet so far ..cause all my appliance in main house been replace with newer ones that does not over used the amps even breakers are oversize .yes ..i beleive your correct that its only 30amps for stove vs 60amps breaker in used while primary HVAC..using 60AMPS breakers while box inside the house that used electric heater for the home been replace since blower fan is not overamperage anymore while heater is not as well..so its 30amps or 40 amps..depending how long its on but during summer its easy for the load since condenser kicks in ..its only 30amps..but my surprise its lot less due to updates to refrigerant that use less power for condensing when its still new for the age 1yr old so far...but my question to that question is i been searching online if its necessary add 4th wire to panel to panel that connect each other with ground..i am planning to do so to keep up to code when subpanel is not bonded and box is grounded to ground rod..so every 110v outlets are grounded to earth while neutral that return to the source is grounded to main panel bonded neutral and grounds with its main ground rods..since the box been their since 2003...since ITE brand been bought out by Siemens since the design is all same with SquareD homeline and GE brand breakers QO breakers ..not very special for this home..they keep it simple and normal that been working since 90's and over 2000's so far...yes our home is GCFI protected in bathrooms and washer room..but stove and dryer no..its regular outlets since both are in main house ..not in detached garage back area since its only regular outlets since my surprise FPE old panel...i see many flaws in them..well hots bus part are separated between in middle from both ends..so both halves is independent to 120v leg while neutral is floating to right side on plastic bottom what its attach to...while ground bus bar is separated from anywhere in box is not touching neutral bus bar and its grounded to the box frame while thick gauge wire is attach to earth ground rod..i did examine closely and wondering why its 3 wire feeding only ...then i notice on bottom of neutral bus bar lug ..cause it comes 2 lug screws one for white wire coming from main panel..and bottom ..their was a bare wire been cut off for unknown reason..and wondering it used to be attach as jumper to ground bus bar when ground rod is next to detached building ...then also notice 2 50amp breakers on top..one for each leg but nothing is attached to them..my guess this panel from FPE did is oldschool way to get 240v...is put one breaker on each leg ..makes sense to me but nobody is doing this anymore since double pole breakers exists for this reason..they intended to be more safe than using 2 breakers same time ..its very similar to my old house i used to lived...2 hots, each feed right and left...the way they wire it...is used both breakers each side to get 240v ...very dangerous back then but the rules are the same ...bonded from main panel for neutral and ground ..and grounded to rod and water galvanized pipe faucet..., i grew up in that house for over 20 years until i moved out to bigger home like this one i am mentioning about this FPE panel that i recongize from..only difference is its the subpanel...that been bother me for awhile since i move in..the seller who sold this home went through many opinions and many contractors while county and city pass inspected many times, one thing i did notice the seller..it upset more when house title holder who holds title..is reading the documents of house history inspections and issues ...i notice this old man ..was getting frustrated with banker lawyers when we are in signing process to give title transfer the home to new home owners ..he want to rush it got me suspicious about him with whole process..why takes too much time and ask more money..on clossing date than origninal was ask for..i wish i could check or hired my owned inspectors but this man ..rush us to final day..i hope i made right decison buying this house that we like but also we gonna get 2nd opinion with newer homes that been built up to code than 1987 homes that seems still safe ....but my old house is built since 1973..that my father raise me been safe since but wiring wasn't sure back then..so just maybe its roll of the dice for everyone..

You do have problems with the HVAC but listen to what I told you about your buildings and your electrical issues are simple fixes. You want it safe and come to us for advice then please do as I advised

 

[DRIVAN]

You do have problems with the HVAC but listen to what I told you about your buildings and your electrical issues are simple fixes. You want it safe and come to us for advice then please do as I advised

currently , i don't have any problems yet..house is wired like it is when i bought the house..nothing change in main panel..only difference i did is replace the subpanel from FPE to SquareD homeline 100AMP box since its only 60AMPS feeding through it..also it didn't have issue with light and plugs only issue is half the plugs only work but nothing is way off on those 3 small breakers..2 20's and 1 15amp...what surprise me the pair of 50 amps above it was never attach anything to it ..like i said when replacing the subpanel, all i did copy over what was wired previous carefully from photo i took from my phone and label each hot to amperage was before..so i don't get it mix match breakers amperage..the light switch is probally 15amps while outlets is pair of 2 breakers nothing more ..all i want is add in mini split since my back building never have ac to cool with and no windows to put a window unit..my best guess i want to keep it low as possible in power..18k btu is good enough for that application i did for that..run new 20amp double pole breaker and run conduit to panel and to fuse disconnect box for split system..everything still working as should at first...cause when i turn on the 60amp breaker..it did caution me at first switch that cause something go wrong like light switch to 15amp breaker was not working is causing imbalance to the rest..strangly when i reset the 60amp breaker again from main panel..it start to work again better than before ...so my guess the same problem is wiring from 15amp breaker was never was for light switch ..the other 2 20amps got my suspious that both share with light outside and inside for one 20 amp while other 20amp is share with plugs ...so i just remember 2014 the 15amp from old panel was never ON in the first place, i been wondering for all those years why it doesn;t do nothing at all..cause building is split building between main big room that could turn into game room or extra living room or bedroom depending what i do with it..and extra room next to it ..its barebone storage room for yard equipment.. their was incomplete wiring to incomplete switch that attach nothing else to dead end wiring from outlets ..