Sub Panel

House Repair Talk

Help Support House Repair Talk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
You can, just don't terminate them in the same panel. The better plan is the run a larger conduit and conductors to a single sub panel where you have the ability to increase the breaker, as the demand changes, and you have far less chance for an explosion if someone who doesn't understand makes an erroneous assumption.
 
You can, just don't terminate them in the same panel. The better plan is the run a larger conduit and conductors to a single sub panel where you have the ability to increase the breaker, as the demand changes, and you have far less chance for an explosion if someone who doesn't understand makes an erroneous assumption.

So all in all running the 2 sub panels off 60 amp breakers will be just fine and if i ever need to change something i can cross that road when I get there.
 
Sorry to be getting in on this late . Do you have a main in your existing panel ? ( In the Garage ? ) What brand is it ?

Or is the main outside ?

Photos would help old guys like me . :)

Best of luck , :)
Wyr
God bless
 
Sorry to be getting in on this late . Do you have a main in your existing panel ? ( In the Garage ? ) What brand is it ?

Or is the main outside ?

Photos would help old guys like me . :)

Best of luck , :)
Wyr
God bless

The main is the in the house in the basement. There is a single overhead line to the garage to run a couple lights currently. I don’t know the brand as of right now but I will know Friday as I’ll be there.
 
If the existing panel is Federal Pacific Electric , parts / circuit breakers are expensive & not very desirable . they often do not trip when they should . In that case , I recommend you replace it with something like Sq D Homeline . A large enough loadcenter ( panel ) to take care of all of your future needs . ( Or , maybe Cutler Hammer / Eaton . )

Not that expensive to DIY , but you may not be up to it , or not ?
 
If the existing panel is Federal Pacific Electric , parts / circuit breakers are expensive & not very desirable . they often do not trip when they should . In that case , I recommend you replace it with something like Sq D Homeline . A large enough loadcenter ( panel ) to take care of all of your future needs . ( Or , maybe Cutler Hammer / Eaton . )

Not that expensive to DIY , but you may not be up to it , or not ?

I’ll do the work. Im hoping it’s sq D. The new panels will be sq D for sure. I just want to make sure the way I planned it out will be ok to do that way.
 
I want to keep the main service at 100 amps. Take out 3 breakers and move them to a sub panel, since there is only one open slot. taking out the 3 breakers will give me 4 slots to run 2 60amp breakers to run 2 sub panels. One sub panel next to the main and one sub in the detached garage. I want to run 60 amps to the garage because i will be putting a 20 amp welder in there which will rarely be used along with miter saw table saw and so on. All the lighting will be LED on a 15 amp breaker and roughly 4 15 amp outlets excluding the 20 amp outlet. I know that only adds up to 50 amps so I would have space to add another 15 amp if need be. The sub in the house would have 1 extra space as well. this would put me in the same boat as now with only having one open breaker slot, but i would have everything else done this way. Since breaker panels are only $20 a piece and breakers aren't much this would be the most cost effective way for me except for the expensive 4 gauge wire to the garage, but it is what it is there. I seem to see this is what people do, but if this is a recipe for disaster then I wont do it this way. I don't care about extra breaker slots at the moment.
Kristofor

Allow me to suggest an alternative approach. Instead of filling up your existing panel with those 2 double pole 60 ampere breakers you may want to consider installing a Main Lug Only (MLO) panel which is rated for 200 Amperes and Listed as suitable for use as Service Equipment. The MLO Service Equipment will have not more than 12 slots in it so that it will never have more than 6 double pole breakers installed. The MLO Service panel would contain the breakers that would be your new Service Disconnecting Means. That panel would go between your present panel and your meter. You would then install the breakers that feed the existing house's panel and the panel in the detached garage in the new Service Disconnecting Means enclosure. Not having any pictures of your home to go by I am going to have to do a little guessing here. When this type of arrangement gets installed the new Service Disconnecting Means often gets mounted on the Outside of the building that already has electrical service. That is because it makes it easier to run the Feeder/s that will supply the other building or buildings. If that is the approach that is taken then the new MLO Service panel will have to be Rain-tight. The type most often used for that is a National Electrical Manufactures Association (NEMA) Type 3R. Do not plan on using the other slots in the Service panel for other individual loads unless they are 240 volt only with no neutral in the circuit or they are greater than 30 amperes. If you do not put those 2 60 ampere feeder breakers in your existing house panelboard you may not need an additional panel in the house. If you do need an additional panel in the house you can supply it from an additional double pole breaker in the new MLO Service panel.

Adding up the ampacity of the breakers in a panel is not how you determine what size of supply it needs. You will have to do a residential service calculation. There are several work sheets on line that will help you to do that. Calculating the service load for the premises will tell you whether you can use 100 Ampere Service Conductors to supply the total load. If the calculated load is greater than 100 Amperes then you will have to upgrade the size of the Service Entry Conductors to the size derived from the calculation. Not doing the calculation will put you at risk of nuisance tripping of your present panels main breaker or of overloading your Service Entry Conductors.

If you need help just ask.

--
Tom Horne
 
That is more or less what I did when I upgraded my service to a 200 amp meter base and installed a 200 amp 12 space N3R loadcenter .

2p - 30 - dryer

2p - 50 - range

2p - 30 water heater

2p - 100 - kitchen loadcenter on opposite side of the wall

2p - 40 - " charging station " for the Nissan Leaf we had in the past

2p - 30 spare

However , I am uncertain if the OP is up for that extensive of a project , at this time ?

That is why I suggested changing out the existing loadcenter that only has 1 space left . With a 30 or 40 space MLO loadcenter .


Best of luck to you , :)
Wyr
God bless
 
I’ll do the work. Im hoping it’s sq D. The new panels will be sq D for sure. I just want to make sure the way I planned it out will be ok to do that way.
If you buy the same brand / style loadcenter that you have now , you likely can re-purpose the existing circuit breakers and save a little $$$ .

Best of luck , :-0
Wyr
God bless
 
That is more or less what I did when I upgraded my service to a 200 amp meter base and installed a 200 amp 12 space N3R loadcenter .

2p - 30 - dryer

2p - 50 - range

2p - 30 water heater

2p - 100 - kitchen loadcenter on opposite side of the wall

2p - 40 - " charging station " for the Nissan Leaf we had in the past

2p - 30 spare

However , I am uncertain if the OP is up for that extensive of a project , at this time ?

That is why I suggested changing out the existing loadcenter that only has 1 space left . With a 30 or 40 space MLO loadcenter .


Best of luck to you , :)
Wyr
God bless
I’m looking to do the quickest and cheapest but yet safe and effective due to being on a time constraint and budget.
 
So all in all running the 2 sub panels off 60 amp breakers will be just fine and if i ever need to change something i can cross that road when I get there.
Please use one of the on line "electrical service load calculators" to verify that the entire load is within the capacity of the 100 ampere breaker.

--
Tom Horne
 
Kristofor

Allow me to suggest an alternative approach. Instead of filling up your existing panel with those 2 double pole 60 ampere breakers you may want to consider installing a Main Lug Only (MLO) panel which is rated for 200 Amperes and Listed as suitable for use as Service Equipment. The MLO Service Equipment will have not more than 12 slots in it so that it will never have more than 6 double pole breakers installed. The MLO Service panel would contain the breakers that would be your new Service Disconnecting Means. That panel would go between your present panel and your meter. You would then install the breakers that feed the existing house's panel and the panel in the detached garage in the new Service Disconnecting Means enclosure. Not having any pictures of your home to go by I am going to have to do a little guessing here. When this type of arrangement gets installed the new Service Disconnecting Means often gets mounted on the Outside of the building that already has electrical service. That is because it makes it easier to run the Feeder/s that will supply the other building or buildings. If that is the approach that is taken then the new MLO Service panel will have to be Rain-tight. The type most often used for that is a National Electrical Manufactures Association (NEMA) Type 3R. Do not plan on using the other slots in the Service panel for other individual loads unless they are 240 volt only with no neutral in the circuit or they are greater than 30 amperes. If you do not put those 2 60 ampere feeder breakers in your existing house panelboard you may not need an additional panel in the house. If you do need an additional panel in the house you can supply it from an additional double pole breaker in the new MLO Service panel.

Adding up the ampacity of the breakers in a panel is not how you determine what size of supply it needs. You will have to do a residential service calculation. There are several work sheets on line that will help you to do that. Calculating the service load for the premises will tell you whether you can use 100 Ampere Service Conductors to supply the total load. If the calculated load is greater than 100 Amperes then you will have to upgrade the size of the Service Entry Conductors to the size derived from the calculation. Not doing the calculation will put you at risk of nuisance tripping of your present panels main breaker or of overloading your Service Entry Conductors.

If you need help just ask.

--
Tom Horne
The garage does not have a panel right now. Then I will have open slots to run a 60 amp to the garage in the mlo. I could also switch any breaker larger than 30 amps to the MLO which would open up more slots in the main. Now wouldn’t that be the same as putting 60 amp breakers in the main for electricity draw if the main service isn’t enough? I would run the mlo in the house then trench the yard to the garage for new service there. Put a 100 amp box in the garage but fed with a 60amp breaker cuz the 100 amp box is way cheaper to buy. The MLO sounds easy to install as I could just kill the main use the feed through on the main to supply the MLO. Is that correct? Next question yis if the house is 100 amps would I would want to keep the MLO low on amps to make sure the MLO has enough supply? Is that correct? I see you say to install it between the meter and the main that is currently there though. Is that the better option then running after the main using the feed through on the main? I’m sure I confused you a little there sorry.
 
Last edited:
Can you post some photos of your existing installation .

Sounds like you may have to do this in phases .

Best of luck , :)
Wyr
God bless
 
If everything will not run off the existing 100 amp main , then the whole ball game changes . And the OP will have to either change plans or change expectations ( what can be done with the existing service ) .

And the probable budget gets larger , quickly .

Best of luck to you , :)
Wyr
God bless
 
The garage does not have a panel right now. So if I put the MLO in then I supply the existing house panel with a 100 amp breaker off the mlo. Then I will have open slots to run a 60 amp to the garage in the mlo. I could also switch any breaker larger than 30 amps to the MLO which would open up more slots in the main. Now wouldn’t that be the same as putting 60 amp breakers in the main for electricity draw if the main service isn’t enough? I would run the mlo in the house then trench the yard to the garage for new service there. Put a 100 amp box in the garage but fed with a 60amp breaker cuz the 100 amp box is way cheaper to buy. The MLO sounds easy to install as I could just pull the meter to kill the power to the house run the lines from the meter box to the MLO then from a 100 amp breaker in the MLO to the main with the existing wire that fed the main from the MLO to the main. Next question is if the house is 100 amps I would want to keep the MLO low on amps to make sure the main has enough supply? Is that correct? I’m sure I confused you a little there sorry.
You will have to replace the cable between the MLO and the panel with a 4 wire cable. The cable must be 4 wire because the Equipment Grounding Conductor (EGC) must be kept separate from the neutral everywhere except at the service equipment which would now be the NLO panel. Buy the 4/0 cable even though you plan to use a 60 ampere breaker. That way if you end up needing to increase the capacity of the whole service you won't have to replace that wire when that time comes. You would then buy a couple of the add on Equipment Grounding Busses and put them in the house panel. Take all of the EGCs off of the neutral buss and move them to the new add on equipment grounding busses. You then remove the main bonding jumper from the house panel so that there is no longer a connection between the neutral and the cabinet which encloses the house panel board. The MLO Service equipment will come with a new bonding jumper that you will install in it.

Crucial in all of this is to do the Service Load Calculation to determine that your present Service Entry Conductors can carry the actual load.

--
Tom Horne
 
Back
Top