View Full Version : Wiring Plan - Do I need a subpanel??

08-04-2008, 01:38 PM
I'm trying to develop a wiring plan for my basement. Below is a wattage circuit evaluation. I only have 6 open circuit breakers, and based on the evaluation below it appears I need more. Do I need to go to a subpanel. On the surface, do you have any suggestions?

#1 20 amp
Home theater System 1200
lights 8 520
Outlets 12 1200
Total 2920

#2 20 amp
TV, Xbox 550
Lights 7 455
Pool table area lights 4 260
Outlets 11 1100
Total 2365

#3 20 amp
Computer, monitor, printer 1200
Lights for PC area 2 130
Home theater soffit lights 9 585
Closet fixture 1 65
Total 1980

#4 20 amp Bathroom
Vanity light 3 195
Shower light 1 65
Fan / Light 100
Outlets - GFI hair dryer 2 1200
Hall fixtures 2 130
Stair wall sconce 1 65
Total 1755

#5 20 amp Kitchen - no oven
Microwave 800
Refrigerator 750
Cans - island, kitch 6 390
Outlet - corn, coffee 3 300
Total 2240

#6 20 amp Workroom
Workroom - outlets tools 1500
Lights 8 520
Closet fixture 1 65
Dehumid 650
Outlet to kitchen island - popcorn popper 1200
Total 3935

08-04-2008, 07:24 PM
I must ask the question, are you planning having 100 watts connected to every receptacle with all those lights burning at once?

The bathroom receptacle MUST be on a 20 amp circuit that nothing else is connected to with the exception of any thing in that same bathroom ie the lights.

08-05-2008, 12:42 AM
I ran seperate circuits for my fridge, microwave and dishwasher to avoid any issues. Obviously your short on circuits but if you go the subpanel route it's something to think about.

08-05-2008, 06:42 AM
I don't plan to use 100 watts in each outlet. What wattage do I assume in my plan for outlets that I currently don't know how they will be used.

Do you suggest a different circuit for lights and another for outlets - rather than the zone method I am using?


08-05-2008, 07:09 AM
#1, 2, and 6 are already overloaded according to your calculations, and #5 is also because of the appliance mix. If the refrigerator starts while the microwave is on it might trip the breaker. A sub panel or split breakers, if those slots will accept them, will give the reduced loads you need.

08-05-2008, 08:17 AM
220.12 of the NEC requires 3 watt per square foot for the lighting and general purpose receptacles.

The kitchen and bath in your notes will require a total of three 20 amp circuits, two for the kitchen and one for the bath. These circuits cannot supply any other outlets except for the bath circuit and it can only supply outlets in that bath.

The bath circuit can not supply these:
Hall fixtures 2 130
Stair wall sconce 1 65
Total 1755

The small appliance circuits for the kitchen can not supply these:
Cans - island, kitch 6 390
Workroom - outlets tools 1500
Lights 8 520
Closet fixture 1 65
Dehumid 650

The rest is 3 watts per square foot divided by 120 volts and again divided by the size of the circuit breaker being used. The lights and receptacles will never be fully loaded is the reason why it is only 3 watts per square foot.

As with all electrical installations it is important to have them properly installed. Now comes the question of saving money by doing it yourself or saving your home by paying a qualified person to make the installation.

The fact that you are posting your question on a Do-It-Yourself site is proof that you are in over your head.
To listen to a bunch of wannabes on a site such as this and then trying to make the installation yourself is just like striking matches and throwing them on the floor to see if the house will burn down.

The fact that no one has pointed out these defects in your post is more than enough to let you know that no one as yet has answered your question that has enough knowledge to be giving you answers.

The fact that something works is not proof that it is done correctly nor that it is safe.
Please hire a qualified person to at least assist you with your installation before you have spent a bunch of money for something that is neither safe nor compliant.

08-05-2008, 08:33 AM
So far as installing a subpanel or wiring everything to the main panel, I look at this as a cost/amount of work thing.

It might be less expensive in some cases to install a subpanel. In other cases more expensive. For example it may cost a young fortune to upgrade the main panel to hold all the additional circuits, and would cost much less to install a subpanel.

Or if running a bunch of wires back to the main panel would be quite difficult, maybe just running one wire and installing a subpanel would be easier.

Also is there room for a subpanel somewhere or not? If not, then wire everything to main and do what is needed there to accommodate the additional circuits.

Then having a subpanel in a certain location would mean that it would be easier to add new circuits in that area in the future. So consider that as well.