Add another subpanel or redo the entire thing?

[mktbully]

So here's the situation...i would like to add circuits for the garage and other places around the house..maybe even a 230V but the panels are all full.

the main appears to be a 100amp panel. there's also a 50amp (i believe) subpanel that comes off the main panel.

so what are my choices here?
there's enough wall space for another subpanel if needed..but would that be pushing it? should i buck up and just get a bigger main panel and have everything in one place?
at what point am i maxing out the service line coming in?

the house was built in the 30s but i do see a lot of updated wiring (romex) so that's a plus.

so what to do?

 

[rickairmedic]

I would go ahead and bite the bullet and upgrade the main panel to a 200 amp . I would say you are already close to overloaded on what you have if your not actually overloaded .

Rick

 

[mktbully]

i assume if i replace the panel to 200 amps i will have to upgrade the service coming in?

the house runs on oil heat (will convert to gas heat) and gas hot water.
i would like to run a 230v compressor and perhaps add 3 zone split air conditioning some time in the future that's why i'm inquiring about additional capacity.

 

[rickairmedic]

Yes the service entrance would most likely have to be upgraded as well but it is something that will be well worth it when it comes time to add toys to the garage .My house had a 100 amp panel and service when I got it . I had a welder at the time thata required a 125 AMP circuit needless to say I upgraded . The only saving factor on my part is I own an HVAC company and my neighbor owns an electric company so I had him pull the permit for me and lend a hand here and there . I picked up the panel and everything else I needed myself at a wholesale supply house.I think I spent maybe $400.00 total but if you have an electrician do it it will be aloooooooot more expensive depending on where you live.

Rick

 

[mktbully]

i'm in NY so yeah it's going to be a LOT more expensive.

 

[Aceman]

I would go ahead and bite the bullet and upgrade the main panel to a 200 amp . I would say you are already close to overloaded on what you have if your not actually overloaded .

Rick

How do you know that? He hadn't mentioned square footage, gas or electric appliances or what kind of loads his old 1930 house has.

There is a difference between out of spaces and overloaded. Making a blanket statement that 100 amps isn't adequate with almost zero information on the subject is silly IMO.

Instead of telling him he needs to spend money to upgrade($$), why not suggest he contact a local electrician for a consult, he can do a load calc.....

 

[rickairmedic]

How do you know that? He hadn't mentioned square footage, gas or electric appliances or what kind of loads his old 1930 house has.

There is a difference between out of spaces and overloaded. Making a blanket statement that 100 amps isn't adequate with almost zero information on the subject is silly IMO.

Instead of telling him he needs to spend money to upgrade($$), why not suggest he contact a local electrician for a consult, he can do a load calc.....

My opinion is based on my own experiance . My garage alone eats up almost 100 amps if you account for the Welder , Compressor , Drill press ,TV , Lights,and on and on . The welder is on a 50 amp circuit the compressor is on a 30 amp circuit theres 80 amps and I havent even looked at all the lights or other tools . I dont know anyone personally that is ( using their garage ) that has 50 AMPS or less going to their garage . Your right though I should have asked what the OP plans to do in his garage but knowing from his original post he is planning for a 220 air compressor it made sense he wasnt planning to polish his Lambo ontop of the exquisit tile floor .


Rick

 

[walrus]

My opinion is based on my own experiance . My garage alone eats up almost 100 amps if you account for the Welder , Compressor , Drill press ,TV , Lights,and on and on . The welder is on a 50 amp circuit the compressor is on a 30 amp circuit theres 80 amps and I havent even looked at all the lights or other tools . I dont know anyone personally that is ( using their garage ) that has 50 AMPS or less going to their garage . Your right though I should have asked what the OP plans to do in his garage but knowing from his original post he is planning for a 220 air compressor it made sense he wasnt planning to polish his Lambo ontop of the exquisit tile floor .


Rick

Adding up breakers isn't the load, I doubt that compressor when running is at 30 amps, the inrush at start up is above 30 but once running not

 

[rickairmedic]

Adding up breakers isn't the load, I doubt that compressor when running is at 30 amps, the inrush at start up is above 30 but once running not

Maybe not but I would rather have more than enough power available than 10 amps less than I really needed .


Rick

 

[walrus]

Maybe not but I would rather have more than enough power available than 10 amps less than I really needed .


Rick

Thats why you figure loads and size accordingly.

 

[paranoid56]

Adding up breakers isn't the load, I doubt that compressor when running is at 30 amps, the inrush at start up is above 30 but once running not

this. i dont think you will be running them all at the same time.

 

[sberry]

I have never seen a 60 tripped in a home garage.

 

[hidollartoys]

I have 50 amps in my detatched garage and have never tripped the breaker. I have 3 welders, plasma cutter, 220v compressor, drill press (you get the picture). Since it is usually only me in there only one tool is being used at a time. I do not have any heat or air.

In my opinion, unless a person is going to run a 10 or 15 hp compressor, weld a ship or run a machine shop 50 amps would probably be enough.

I know, I know you can never have enough power, air or shop space. (grunt,grunt,grunt)

 

[jshillin]

I just installed a 50 amp sub panel in my detached garage over the weekend. The previous owners had my entire garage on a single 15 amp circuit...

 

[mktbully]

just to give you an idea what i'm working with...

main panel

subpanel

so....run another sub panel or do i have to merge the two panels to one so i can add more capacity?

 

[tfi racing]

It all depends on how many breakers you want to add,and your budget.I see space for about 18 more circuits with the panels you have if you really wanted to max them out with tandem breakers.

 

[walrus]

.I see space for about 18 more circuits with the panels you have if you really wanted to max them out with tandem breakers.

I doubt the NEC will allow this

 

[mktbully]

i'm looking to add 6-8 more. (4 would be good...6 would be ideal...8 is having 2 spares).

i don't want to half **** it so doubling up or short cuts will not do it.
i'm annoyed that the breakers don't line up w/ the cover.

 

[mrb]

I doubt the NEC will allow this

why not? the number of tandems that can go in the panel is physically limited. If theyll fit in his panel its ok. For example, if a panel is a 20/40 theres nothing wrong with putting 20 tandem breakers in it. If the panel is a 20/30 for example, you will only be able to fit 10 tandems in it.

 

[walrus]

why not? the number of tandems that can go in the panel is physically limited. If theyll fit in his panel its ok. For example, if a panel is a 20/40 theres nothing wrong with putting 20 tandem breakers in it. If the panel is a 20/30 for example, you will only be able to fit 10 tandems in it.

You have to read the panel instructions, if its a 20/40 then fine but not all of them are.

 

[porschedude996TT]

So here's the situation...i would like to add circuits for the garage and other places around the house..maybe even a 230V but the panels are all full.

the main appears to be a 100amp panel. there's also a 50amp (i believe) subpanel that comes off the main panel.

so what are my choices here?
there's enough wall space for another subpanel if needed..but would that be pushing it? should i buck up and just get a bigger main panel and have everything in one place?
at what point am i maxing out the service line coming in?

the house was built in the 30s but i do see a lot of updated wiring (romex) so that's a plus.


so what to do?

You don't say where you are from or give us a clue to what your electrical load is. A 220-240volt 100amp gives you a bunch of capability if your house load is small. Run the calc's on the house and find out how much reserve you have. I had a 100amp panel which gives me 200amp's at 110volts and only had 54 amps calculated load because I don't have an A/C, Electric Water Heater, Electric Stove. Also, dependant on where you live the Electric Company may fund the conductor changeout or you may have to foot the cost youself. Do a little research and find out what you really need and forcast what you want to power in the future.

 

[mrb]

You have to read the panel instructions, if its a 20/40 then fine but not all of them are.

right, the ones that arent wont fit the tandem breakers

 

[mktbully]

You don't say where you are from or give us a clue to what your electrical load is. A 220-240volt 100amp gives you a bunch of capability if your house load is small. Run the calc's on the house and find out how much reserve you have. I had a 100amp panel which gives me 200amp's at 110volts and only had 54 amps calculated load because I don't have an A/C, Electric Water Heater, Electric Stove. Also, dependant on where you live the Electric Company may fund the conductor changeout or you may have to foot the cost youself. Do a little research and find out what you really need and forcast what you want to power in the future.

need a little help here...
how do i run the calcs on the house?

 

[porschedude996TT]

I'll get the information tomorrow morning. I think there are two ways to do it per the NEC. Basically you add using volt/amperes as a unit. Add the lighting based on square footage of the house 3V/A's per square foot, add fixed in place appliances, two 20 amp receptacle circuits for the kitchen, your heating/cooling load which ever is higher, 220v water heater, 220v stove and you get an actual near worst case load. By near I mean that you could purposely go around the house and turn everything on, plug everything you own in and turn it on and come up with a higher value, but that is not a normal condition. It is very different than a commercial / industrial building where everything is hard wired and could be running at a peaked out.

I'll get the formula in the morning. It took me several reads to get it to sink in...but it makes perfect sense.

Added 04/22/2009

Basically you will be adding up the watts of actual values or an average that the NEC has come up with. The unit that they call Volt-Amperes or VA’s is more commonly refered to as watts or volts times amps.

Lighting Load = (Outside Dimensions of you Building on that service) L X W X 3 VA's.
Plus
3000 VA's for Small Appliance (Kitchen) - Minimum 2 or how many you have, 1500 VA’s each.
Plus
1500 VA's for Laundry Circuit.
Plus
Larger of the Heating/Air Conditioning Load in Watts (VA's) or if you don’t have a A/C, you can use the actual tag rating from the appliance. If you can’t find the tag, figure 1500 VA’s.
Plus
Fastened in place appliances the sum of (Dishwasher, Electric Range and or Wall Mounted Oven, Disposer, Trash Compactor, Attic Fan, Electric Water Heater) then multiply by (.75)
Plus
Electric Clothes Dryer 5000 VA’s if you have one, otherwise the Laundry Circuit take into consideration of the motor of a gas-fired clothes dryer.

For the first 8000 VA’s, figure them at 100% of the 8000 VA’s and the for the remainder, multiply by 40% and add that to the first 8000 VA’s.
Sum and Product from above and divide by the voltage and this is the calculated load demand to size your service meter panel and the conductors to service said panel.

Example of a 2000 Sq Ft House with two small appliance circuits in the kitchen, no A/C and mostly Gas Fired Appliances
Lighting (2000 x 3 = 6000 VA’s)
Two Small Appliance Circuits (1500 X 2 = 3000 VA’s)
Laundry Circuit (1500 VA’s)
Forced Air Furnace (1500 VA’s)
Fix in Place Appliances (Disposer 746 watts, Trash Compactor 400 watts, Dishwasher 1200 watts) (2346 VA’s X .75 = 1643 VA’s)

6000 + 3000 + 1500 + 1500 + 1643 = 13643 VA’s
(13643 – 8000 = 5643) x .40 = 2257
8000 + 2257 = 10257
10257 / 120 = 85 amps of calculated load.

Also note that your 240 Volt 100 Amp Panel has a combined capacity of 200 Amps ( two 120 Volt Lines at 120 volts each. So if the loads are balanced each line would only see 43 amps.

 

[Slick6]

If you go here you can access the NEC online. Once you make an account, go to Annex D: Examples in the back of the book and you can see samples of load calculations along with code references.