Will 100 amp service be enough for this equipment?

[tlmartin84]

I have 400 amp service at my house, 300 dedicated to the house and 100 that I planned to run for my shop someday.

Well my plans have grown some. My shop is about 80' from my panel box. I had my electrician stub wire for a 100 amp service out of the house prior to doing any sidewalks.

I looked in my panel and it appears to be 3 - 1 or 2 ga aluminum wires and 1 - 2 or 3 ga wire that was stubbed out for my shop. Is that big enough for an 80' run?

Here is a list of the equipment I will be running. I am typically the only person working the shop so rarely will more than one piece of equipment be ran at a time.

I would say the largest combo that could possibly run would be the Air handler/Heat strips/Air Compressor/Vent Fan/Paint lights.

I really don't want to have to run another 200 amp service.............

Air Compressor 220V 15 amp
Plasma 220v 40 amp
Welder 110/220V 30 amp
paint fan 110/220V 15 amp
Lathe 220V 30 Amp
Mill 220V 30 Amp
Paint Lights 110V 15 Amp
Shop Lights 110V 15 Amp
Various outlets 110V 20 Amp
Air Handler 220V 30 amp
Heat Strip 220V 60 amp
Heat Pump/AC 220V 30 amp
Lift 220V 30 amp

 

[BIMMERBOYZ]

Aluminum #3 even at 90 degrees C is only good for 85A.

 

[tlmartin84]

How can i tell what size it is for sure??

 

[BIMMERBOYZ]

Look at the side of it. Should have a label.

I think you need at least 1/0 aluminum or # 1 copper.

 

[pattenp]

You don't size wire from the 90 degree C column. Generally you use the 75 degree C column for sizing the feeder. #1 Al is good for 100 amps and #2 is 90 amps @ 75 C. But based on your equipment you listed I don't see how 100 amps is enough.

 

[BIMMERBOYZ]

Why does your house need 300 AMP.

 

[theoldwizard1]

Well my plans have grown some. My shop is about 80' from my panel box. I had my electrician stub wire for a 100 amp service out of the house prior to doing any sidewalks.

So the wires were not connected to a breaker in the main panel and therefore did NOT pass inspection, correct ?

I looked in my panel and it appears to be 3 - 1 or 2 ga aluminum wires and 1 - 2 or 3 ga wire that was stubbed out for my shop. Is that big enough for an 80' run?

Does that 80' include the distance inside both buildings ? My SWAG is that it is 2-2-2-4 MHF, but you need to confirm it !

Do you plan on getting the electrical re-inspected when it is hooked up ? The inspector will tell you if you can run a 100A breaker in the main box or if you will have to downsize (70-80A?) in order to protect the wire.

Here is a list of the equipment I will be running. I am typically the only person working the shop so rarely will more than one piece of equipment be ran at a time.

Well that may save you ! Turning off the heat pump, air handler and heat strips for the few minutes you are running the plasma or the welder and you will probably be fine ! Remember, to run the plasma, you need air !


Oh yeah. Did you have a contract with written requirements with the original electrician ? If so he maybe be replacing that wire for you !

 

[BIMMERBOYZ]

If he wants only 100 amps, he must use the 60 degree column. If he goes above 100 amps he can use the 75 degree column. To size his sub panel wire.

 

[tlmartin84]

It is 2-2-2-4, I measured an individual strand and calculated the area.

I had a friend do my wiring, he is an electrician. I just didn't want to have to come out and look and he couldn't remember what he had installed off of the top of his head.

My house is close to 4000 sf with two heat pumps/AC and two air handlers with electric heat. I set the house up for 400 amp service because I needed it. I just hadn't planned on building a shop as big as I am now going to.

My disconnect box has a built in spot for 8 breakers (which were unused, I wanted all of my exterior stuff on the disconnect breakers, didn't work out that way) . Could I pull a separate set of lines from that and possibly place another small panel inside of the shop?

 

[2ManyProjects]

I have 400 amp service at my house, 300 dedicated to the house and 100 that I planned to run for my shop someday.

And how, exactly, are you making that "dedication"?

Electricity doesn't really work that way. Just because you have (for example) a 100A feeder to the shop sub-panel does NOT mean that suddenly 100A less is available for the house. It all depends on what loads are actually running at any given moment.

Well my plans have grown some. My shop is about 80' from my panel box. I had my electrician stub wire for a 100 amp service out of the house prior to doing any sidewalks.

I looked in my panel and it appears to be 3 - 1 or 2 ga aluminum wires and 1 - 2 or 3 ga wire that was stubbed out for my shop. Is that big enough for an 80' run?

Well first, we'd have to really KNOW what wire you're referring to (in terms of both AWG and material) in order to meaningfully answer that.

However, in this case, it's a lead-pipe-cinch that the run length is NOT the problem.

Here is a list of the equipment I will be running. I am typically the only person working the shop so rarely will more than one piece of equipment be ran at a time.

That will help, IF you can really count on this ALWAYS being the case. But this is usually not a very desirable assumption to make -- or at least, to be forced to rely on. It inherently implies that the electrical service to the shop is marginal at best; and "marginal at best" is never a good thing to aim for.

I would say the largest combo that could possibly run would be the Air handler/Heat strips/Air Compressor/Vent Fan/Paint lights.

And I'd say you're right -- and therein lies the problem. Per your list:

Air Compressor 220V 15 amp
Plasma 220v 40 amp
Welder 110/220V 30 amp
paint fan 110/220V 15 amp
Lathe 220V 30 Amp
Mill 220V 30 Amp
Paint Lights 110V 15 Amp
Shop Lights 110V 15 Amp
Various outlets 110V 20 Amp
Air Handler 220V 30 amp
Heat Strip 220V 60 amp
Heat Pump/AC 220V 30 amp
Lift 220V 30 amp

Just the heat strip and the air handler alone (which WILL be used concurrently) add up to 90 Amps, before you turn on a single light fixture or power tool. Notably, that is the absolute MAXIMUM limit for AL 2-2-2-4 MHF.

Further, some of the items on your list appear to be estimated far too low in terms of their current consumption. The air compressor in particular stands out here; even a relatively modest one (such as virtually any of these: http://www.aircompressorsdirect.com/quick_search.php?v=7980) will require at least a 25A circuit (30A being more typically used).

[While I'm picking nits, I'll also suggest that your shop lights be split onto TWO 15A circuits, and that at least two 20A circuits be used for your general-purpose 120V outlets.]

I really don't want to have to run another 200 amp service.............

You probably won't have to. But you probably WILL need to run a new (bigger) feeder to the shop's sub-panel.

It is 2-2-2-4, I measured an individual strand and calculated the area.

Assuming your assumption is correct eyecrazy, I cannot fathom how that is going to be sufficient for all the "stuff" you want to run.

I had a friend do my wiring,

Famous last words.

My house is close to 4000 sf with two heat pumps/AC and two air handlers with electric heat. I set the house up for 400 amp service because I needed it. I just hadn't planned on building a shop as big as I am now going to.

I still don't think the 400A service is going to be a problem. At least, it's definitely not the primary problem. But that shop IS going to need more than a 90A feeder.

My disconnect box has a built in spot for 8 breakers (which were unused, I wanted all of my exterior stuff on the disconnect breakers, didn't work out that way) . Could I pull a separate set of lines from that and possibly place another small panel inside of the shop?

You're going to need a sub-panel in the shop, regardless. It can be as (physically) large as it needs to be in order to provide sufficient branch-breaker slots. The electrical capacity of that subpanel will be determined by the breaker at the other end of the feeder cable.

I take it this "disconnect box" is on the exterior of the house, somewhere downstream of the meter pan? If so, I don't (currently) see any reason why you could not source the shop feeder there. How large a wire you could fit to it will be a function of the lugs on those breakers.

 

[BIMMERBOYZ]

What size wire do you have feeding your Main 400amp service?

 

[theoldwizard1]

Could I pull a separate set of lines from that and possibly place another small panel inside of the shop?

Possibly, depending on codes. It would be a good idea, even if you only ran the heat pump, heat strips and air handler off of this.

The real question is, is this cost effective ? A big part of the cost will be digging the trench and the wire. More 2-2-2-4 would cost about $1.50/foot. I can't find a price for 2/0-2/0-2/0-1 so we can not compare them here. The other question is what is the scrap/resell value of the old wire ? Maybe $0.50/ft ? $0.75/ ft ?

Either way, you won't be able to do what you want in the shop with the existing wire.

 

[theoldwizard1]

The electrical capacity of that subpanel will be determined by the breaker at the other end of the feeder cable.

I am not sure why people don't understand this concept !! Plus they have to understand that the breaker at the head of the feeder is sized to protect the wire, not the the subpanel.

Who cares if you ave a 200A subpanel if the feeder breaker is 100A ! It just means you will have a long way to walk if the feeder breaker trips before the main in the subpanel !

 

[wyliesdiesels]

If he wants only 100 amps, he must use the 60 degree column. If he goes above 100 amps he can use the 75 degree column. To size his sub panel wire.

No! U are misinterpreting that code!

It is 2-2-2-4, I measured an individual strand and calculated the area.

I had a friend do my wiring, he is an electrician. I just didn't want to have to come out and look and he couldn't remember what he had installed off of the top of his head.

My house is close to 4000 sf with two heat pumps/AC and two air handlers with electric heat. I set the house up for 400 amp service because I needed it. I just hadn't planned on building a shop as big as I am now going to.

My disconnect box has a built in spot for 8 breakers (which were unused, I wanted all of my exterior stuff on the disconnect breakers, didn't work out that way). Could I pull a separate set of lines from that and possibly place another small panel inside of the shop?

#2 AL has a MAX ampacity of 90a in this application!

And a detached structure can only have 1 service feed.

Possibly, depending on codes. It would be a good idea, even if you only ran the heat pump, heat strips and air handler off of this.

The real question is, is this cost effective ? A big part of the cost will be digging the trench and the wire. More 2-2-2-4 would cost about $1.50/foot. I can't find a price for 2/0-2/0-2/0-1 so we can not compare them here. The other question is what is the scrap/resell value of the old wire ? Maybe $0.50/ft ? $0.75/ ft ?

Either way, you won't be able to do what you want in the shop with the existing wire.

Read above. A building can only have one service feed.

 

[Aceman]

Well my plans have grown some. My shop is about 80' from my panel box. I had my electrician stub wire for a 100 amp service out of the house prior to doing any sidewalks.

I'd like to see how he stubbed out wire. I've stubbed out conduit for future runs to buildings, equipment, etc but they've never had wire installed in them until the conduit run was complete.

I would say the largest combo that could possibly run would be the Air handler/Heat strips/Air Compressor/Vent Fan/Paint lights.

I really don't want to have to run another 200 amp service.............

Air Compressor 220V 15 amp
Plasma 220v 40 amp
Welder 110/220V 30 amp
paint fan 110/220V 15 amp
Lathe 220V 30 Amp
Mill 220V 30 Amp
Paint Lights 110V 15 Amp
Shop Lights 110V 15 Amp
Various outlets 110V 20 Amp
Air Handler 220V 30 amp
Heat Strip 220V 60 amp
Heat Pump/AC 220V 30 amp
Lift 220V 30 amp

I'll do a rough calc of your load on one phase.

15+15+15+30+60=135 amps minimum.

I'm going to leave out shop lights and receps even though they would normally be included in the calc.

A 100 amp panel isn't going to cut it. Switch your HVAC over to propane or natural gas and you might have a chance.

 

[theoldwizard1]

Read above. A building can only have one service feed.

That is what I thought, but I was not certain !

For what he wants to run, he would needs a 200A panel, 4/0-4/0-4/0-4 MHF and feed from a 175A breaker.

 

[tlmartin84]

It sounds like 100 amp service isn't going to cut it then with the main heat source being electric. It is my fault for not requesting a larger stub out. Like I said the shop is now going to be bigger and have more equipment than I ever anticipated.

I have a 400 amp disconnect box outside the house. It feeds 2 - 200 amp panels in the house. One is loaded full. The other about half.

When I said 300 amps dedicated, I meant calculation wise. 2 heat strips and 2 air handlers in the house is 180 amps, add a well pump, water heater and range, with a few other small appliances and im nearing the 300 mark.

The 200 amp breaker box closest to where the building will be has a patio outside of it. I have no way to run wire after the fact. We ran conduit out beyond it and he placed some kind of under ground connection box. He is a certified electrician and does this everyday commercially so I am sure it was to code.

It was my fault for not sizing it bigger.

It sounds like I need to check my disconnect box and see if I have any terminals there I can get larger wire into, or go to an alternative heat source.

Thanks for the help.

 

[tlmartin84]

This building is right next to a pole so getting a new service is cheaper than running it from my house.

The only catch is there is a minimum usage requirement. I will have to check it and see what it is now. When I checked the last time I wouldn't have reached it (only working 3-4 days a month in the shop) which makes a new service a deterrent.

 

[James-W]

Personally, I think it would make more sense to have the power company run you a new 200 amp service right to the garage. Not sure what the power company does with regards to a new service where you are, but around where I live they will run up to 100ft for free. If the distance is over 100 feet they charge by the foot for whatever distance is over the 100ft, but the cost isn't all that much. If the power does the new service you will have the electrical power you need and it will be done in accordance with all applicable codes.

I am a firm believer in spending whatever the amount of money it takes to do the job right the first time. Having to re-do something usually ends up costing more money, not to mention all the inconvenience associated with it.

Anyway, that's my two cents worth.

PS = Thought I would add this. There is a cost for having the new service and the new meter. The cost is a little less than $10 per month whether I use any electrical power or not. But I use my garage quite a bit, all year around, so to me the $10 is of little or no consequence. The enjoyment I get from having a nice place to work on projects is infinitely more rewarding than the $10 "penalty" I have to pay each month.

 

[tlmartin84]

The intial hook-up cost is nothing other than me paying for the conduit and digging the ditch, the building is less than 40' away from the pole.

That cost is not the issue, it is the minimum usage fee that will get me. Especially during spring fall and summer months when we are not using heat.






Here is a picture of my disconnect box, can I pull another set of leads out of it??? Keep in mind it already has 2 sets coming out of it.

View media item 35654

 

[sberry]

If you want one bill its so much easier and eventually cheaper off of one meter, its why you got 400 in the first place? You can run all that from 2 and a 090 easy minus the heat. If you want the heat it really needs at least a size bigger wire. I think the panel takes a 125 breaker? If its 80 ft to house or 40 to the pole I would have to consider the house if I could just to manage 1 service. That's what that box is for, so you can add.

 

[BIMMERBOYZ]

Could you use the new meter to power the heat for the house? Using the wire that was intended for the garage?

 

[tlmartin84]

I don't think so, that would be 2 services to one building which is against code.

I guess these are my 3 options unless someone comes up with something else.


1. New 200 amp service, cheapest option now, subject to monthly penalty.

2. Live with the 100 amp service and switch to propane/natural gas.

3. Pull larger wires directly from my disconnect box. This is what I prefer, I just don't know if anything about the inside of that disconnect. Can lugs be added to it??

 

[theoldwizard1]

... or go to an alternative heat source.

This get my vote ! A propane furnace would eliminate the heat strips.

Depending on the size and layout of the building, you should look into a multiple outlet mini-split heat pump. Some provide heat down below freezing WITHOUT heat strips. Also with multiple zones you won't need that big air handler.

PS = Thought I would add this. There is a cost for having the new service and the new meter. The cost is a little less than $10 per month whether I use any electrical power or not. But I use my garage quite a bit, all year around, so to me the $10 is of little or no consequence. The enjoyment I get from having a nice place to work on projects is infinitely more rewarding than the $10 "penalty" I have to pay each month.

That is what I thought. $10-$15/month.

 

[theoldwizard1]

2. Live with the 100 amp service and switch to propane/natural gas.

Does that remove the "air handler" also ? Its a big power hog.

 

[tlmartin84]

I'm going to look into some mini splits, any recommendations? It gets pretty cold here 20's most of the time will a mini keep up??

 

[sberry]

I like LP due to the fact it can be used without power essentially. Takes all the major demand off the electric system.

 

[tlmartin84]

They make me a little nervous in a building with a paint booth.

 

[sberry]

The fire isn't sposed to be in the booth. I got a wood stove roaring when I am painting as well as an lp burner.

 

[tlmartin84]

Do any of you know anything about that diaconnect box as far as pulling another set of leads out of it goes.

I know you dont keep the flame in the paint booth. It is just the thought of it. Ive got some good wxplosion stories lol.

 

[theoldwizard1]

I'm going to look into some mini splits, any recommendations? It gets pretty cold here 20's most of the time will a mini keep up??

Mitsubishi seems to be the leader. No personal experience, but 20F should not be an issue.

I like LP due to the fact it can be used without power essentially. Takes all the major demand off the electric system.

Got to agree with you there. But if your going to have AC a heat pump is cheaper than a furnace, unless you can get by with just a wall furnace or one hung from a ceiling/

 

[tlmartin84]

That was one reason i wanted to keep an air handler. Easy a/c install later. And my buddy has two brand new trane air handlers with heat strips i can buy for half price.

 

[sberry]

I know this. A bud has a 30x40 him and a helper worked out of for 20 5 years fed with a number 2 aluminum wire and a 60A breaker. They didn't have heat pump or electric heat but 5 hp air comp and 20A @ 230 AC a few days a year. Never tripped a breaker. They had greedy lights for a long time too.

 

[BIMMERBOYZ]

I don't think so, that would be 2 services to one building which is against code.

There is exceptions to that code. 230.2 A-D

I am unsure if the AHJ, would recognize the exceptions, it was just a thought.

Can you explain on what the penalty is, for the minimum use violation you've
mentioned.

 

[tlmartin84]

I am not sure what the exact dollar amount is here. Some of the other guys have quoted 10-15$ a month.

This doesn't apply to all power companies, but I am pretty sure mine does this. I have to check to confirm but that is the rumor.

Essentially if you don't use a certain amount of kW per month they charge you a flat fee.

So lets say it is 15$ and you only use 5$ worth of electricity for that month they still charge you 15$. While not a big deal it still has the potential to add up over time. If I were to run a business out of it and was going to heat it year round, then a new service is the way to go. Right now with kids and a family I am lucky to be in mine 5-6 hours a week.

 

[jvitez]

I think the OP is making big decisions without the detailed calculations he needs.

tlmartin84: spend some time and determine the actual running power consumption of every piece of equipment, heater, air handler, light, etc., in wattage no amperage. Write down the actual watts used, not the circuit breaker rating of each circuit. I think you're calculations are overestimating your consumption!

Anything considered a continuous load (3 hours or more ) must have the wire and therefore the breaker upsized by 25%. So, your 60 amp heat strips (if 60 amps is actually the breaker rating not the true in-use consumption) would by code use 48 amps or less. That's why calculating with wattage is far more accurate.

Once you've obtained all the wattage consumption numbers, add up everything you could possible by using at the same time, in watts. Is this a one man shop? If so, you probably won't be using your lathe and mill at the same time. Will your paint fan and paint lights be on if you're using your welder? How do you plan on using your shop? Think about this for a bit and add up the numbers.

Now, divide the total wattage you could ever envisage using at the same by 240, not 220. That is the total load of your shop in amps. I bet it will be less your current calculations.

 

[tlmartin84]

OK,

http://www.homedepot.com/p/GE-10-Ga...er-Heater-GE10P06SAG/100133195#specifications

Look at these specs, it list this water heater as being 16.7 Amps. Then the wattage as being 2000 watts. 2000/240 is 8.33 amps.

Which do you use 16.7 or 8.3?

 

[tlmartin84]

Also here is a furnace tag with electric strip heat in it, is the 66.8 amp rating include the strip heat and motor?

View media item 35319
I am assuming it does....

4.3 amps on motor plus 15000/240 = 66.8amps That would be the true rating, the breaker then would be sized at 90 amps? Is that why I am seeing a 30 amp and 60 amp breaker in the panel for the heat unit?

 

[tlmartin84]

Based on Jvitez my maximum load comes in under 100 AMPS.

Air Compressor (5 HP). 15.5 Amps
Paint Fan 5.5 Amps
Paint Lights (12- 4 bulb T8 units) 6.4 Amps
Heat 67.0 Amps

TOTAL 94.4 Amps

 

[JakeKohl]

I'm going to look into some mini splits, any recommendations? It gets pretty cold here 20's most of the time will a mini keep up??

The leading mini-splits (Mitsu, LG, etc.) are good for heating with outdoor temps down to 5 degrees F. I'm astonished at the amount of heat mine put out when the outdoor temps are in the 20's (about as bad as it gets here). It qualifies as "hot" air. They put the 3 yr old heat pump in my house to shame.

However, I'm still not sure this solves your load problem. I'm not terribly experienced with the electrical...but couldn't you put a 200 (or 180) amp breaker in your 2nd (barely loaded) 200amp panel to feed the garage and re-run the service line? It seems like we're spending a lot of time talking about nothing but solutions that have compromises.