Question about power upgrades, 100 vs 200amp?

[sbd4de3]

First off, I'm not an electrician, nor am I versed in much when dealing with electricity.

I do know that I should turn off the main power when changing out receptacles and light switches!!

If any of you have read in one or two of my posts, you may recall that I'm going to be putting a building behind my house for garage/workshop needs.

I've been trying to find and read all of the threads dealing with new construction of buildings and have seen many of you saying that you're upgrading the house from 100amp to 200amp and running 100amp to your building...

If you've done this upgrade or know of somebody that has, could you answer the following questions for me please? Thanks, in advance!

1. What is the purpose for this upgrade in your case?

2. Was it recommended by the local electrician, a buddy of yours, was it read about on GJ and you just jumped on the bandwagon or was there actual need for you to upgrade?

3. How much does the upgrade from 100 to 200 cost on average or specifically in your case?

4. How would one find out what the amps are for your own house?

5. If I'm putting in a building that I'll be using a welder or two, a grinder and a chop-saw for metal as well as various wood working tools, should I upgrade my house to 200 and run 100 to my building?

I think that's all the questions I have, thank you for any responses I get and for hopefully helping me understand the necessity.

Also, if you know of any other areas of discussion related to this topic, please fill me in!

Love GJ, serious wealth of knowledge to be had by reading!!
Steve

 

[nadogail]

My house has been upgraded from 100 Amps to 200.

We replaced the electric coil burner cooktop with an induction cooktop. The old cooktop replaced an electric stove the house was originally built with. The stove drew 30 amps, the induction cooktop 60.

The stove had an oven, the wall oven we are now using draws 40 amps.

So our cooking appliances changed from 30 amps to 100.

We added central air conditioning, a 50 amp load.

We did eliminate the electric dryer, actually changed to a gas dryer, electric dryers draw 30 amps.

Our home office has three computers, a laser printer, and a shredder; all in what used to be a bedroom. This is a significant increase in electrical load in that one room. We added two 20 amp circuits.

The upgrade took a new service panel, including the mast and heavier wires from the pole.
The sub panel was also replaced. The 90 amp aluminum wire from the main panel to the sub panel was replaced with heavier copper.

I don't recall how much all of this cost, but the electrical labor and materials cost thousands, not hundreds.

Have an electrical contractor look at your specific project to make a proposal, because every job is different.

I shopped and got discounts because we are in the rental property business.

 

[tel0004]

How much you need really depends on what you do, and what might be running at the same time. 99% of the time 100 amps is plenty. But if the AC is on, a load of laundry is in the dryer, you have something in the oven, and you go to use the welder, you could hit your limit and trip the breaker.

What you are installing the the garage is somewhat irreverent. I'm assuming you will not be using both welders and the chop saw at the same time. The most powerful combination of tools that will be used at one time is whats important.

If you want to know how many amps you have, go to your breaker box. The main breaker (top center, or top left) will have an amperage listed on it.

For example, this house has 100 amp service:
http://www.callsouthernelectrictoday.com/wp-content/uploads/2012/10/breakerbox.jpg

How big is the workshop going to be, and how much future proofing do you want? If you run 20amps for lights, and 2 20 amp circuits you don't have a ton of room for expansion if it is a large shop. If its a smaller building with just a few tools, then you should be fine, but power could be limiting on a larger building if you need to expand.

To give an extreme example, my parents live in Montanna. They don't use the AC more than 1 week a year. Stove and Dryer are gas. They could build a shop draw lots of power and be fine since the house is drawing so little, so there is no easy answer without knowing what you want and how you would use it.

I would expect a conversion to cost around 2k-3k as a rough estimate.

 

[Slowgsr]

My house has 100a main, it feeds my shop with 100a main.
Electric dryer & spa. I can't be in two places at once

 

[woodzy]

It seem logical to say if you are going to add a workshop and that workshop will have some large motors running things like a cabinet saw, air compressor, welder, or other large load items, you would want a 100amp service there. That does not mean that you will use all of that but it leave your room for future upgrades. If you current house had a 100amp service, and you run a smaller service to the workshop, there is a good chance every time you turn on these high HP motors, the lights will dim in the house.

I am fortunate, my house and shop are about 350' apart and I have two 200 amp services both with their own 10K transformed off the main line. As the consumer power rep told me, I have more power available to me than anyone on the street. The next time I leave this property will be on a gurney so depending on how long you plan to be at your location, best to plan for the future and don't skimp.

 

[pattenp]

Well without a whole lot of detail of what's in the house using power and what you'll be using in the shop all at once it's hard to say what you need to do. A suggestion is if you have space in your current 100A house panel is to add a double pole 60A breaker. Run 2-2-2-4 aluminum MHF with a combination of 2-2-2-4 SER if you can't get conduit to the panels. Put in a 100A main breaker panel in the shop. Try it with the 60A feed and see how it goes. If you find you have no issues with power shortage or tripping back at the house then you're good to go. You can then push the 60A up to 80A or 90A and see how it goes. If you have problems back at the house then upgrade the house service to 200A. The 2-2-2-4 aluminum feeder will take up to 90 amps and most likely will be all you need unless you plan on putting in HVAC system in the shop. This is the cheapest thing to try before upgrading the service. A service/panel upgrade may be in the range of $1800 to more than $2000.

 

[wyliesdiesels]

The only way to know if u need a service upgrade is by doing load calcs.

 

[trainer]

When I built my garage, I put a new 200 amp service in the garage that feeds the existing 100a panel in the house. I saved on labour because the existing panel stayed intact and I have lots of power available in the shop.

 

[Hpozzuoli]

Load calc needs to be done

Wife is running dryer while making dinner using microwave and electric stove with most of the lights on in the house. You then go to the shop and try to weld something. Lots of darkness to follow. Add window AC units in the summer and you will see why a second service is needed.

 

[theoldwizard1]

1. What is the purpose for this upgrade in your case?

The only way to know if u need a service upgrade is by doing load calcs.

In many (probably most) cases and upgrade to your load center (breaker box) is required because of a lack of open breaker slot cause by some other remodeling project and not because you load requirements have gone up.

A typical kitchen remodel from a pre-1980s kitchen might require 4-6 ADDITIONAL circuits. Any load center from a house built in that time frame is likely to have no empty slots in the load center. Most 24+(?) slot load centers are set up with a 200A main and changing the meter base and entrance cable are NOT that much additional money.

 

[DonPowers]

I have a 100 amp panel in the house and a 200 amp panel in the garage. For me, it isn't about how much power I will use at any given time but the number of circuits that are available.

My house panel has slots for 16 circuits and to add more I replaced some breakers with minis, which have two breakers in one slot. The garage panel has 40 spaces, which leaves me with room to add more circuits , if needed.

To upgrade the house, I have to change out everything from the mast to the panel, including the meter box. Or, I could install a sub panel or two. Don't have a cost for this.

 

[tel0004]

In many (probably most) cases and upgrade to your load center (breaker box) is required because of a lack of open breaker slot cause by some other remodeling project and not because you load requirements have gone up.

A typical kitchen remodel from a pre-1980s kitchen might require 4-6 ADDITIONAL circuits. Any load center from a house built in that time frame is likely to have no empty slots in the load center. Most 24+(?) slot load centers are set up with a 200A main and changing the meter base and entrance cable are NOT that much additional money.

I agree, although you can get around it by using tandem brekers (legal in some boxes, not all). If need 10 more breakers, replace it. If you need 1 or 2 more, ask an electrician if you can install tandem breakers.

 

[Autorotica]

I had a 200 amp service (meter base) on my home and upgraded it to a 400 (320) when I built my shed. My home had and continues to have a 40 space 200A load center and now the Shed does too.

I had an early version of a "Total Energy Detective" (Google it) in my home so I could see the amount of power consumption I used for about 2 years before we built the shed...

Do I need 200 amps in either building? Not yet, but if I do, I don't have to do a thing.

Another thought.
With a single meter, I am billed at a residential rate. If I had a separate meter, I was told that would be commercial.

Chris

 

[sbd4de3]

You guys are awesome!! Thanks for replying, I now have some ideas to speak to the boss about, and then the electrician. I will mostly be in the shop while the wife(boss) is in the house like Hpozzuoli said, but, I am the one that makes dinner and such, so like Slowgsr said, I can't be in two places at once...

So, I think the best route would be to run another 100 or possibly 200a to the shop to enable running grinders, welders and such without affecting the house power. It's dark now, and cold out, so I don't really want to go outside and check the meter.

 

[Nhrafan26]

I had a 200 amp service (meter base) on my home and upgraded it to a 400 (320) when I built my shed. My home had and continues to have a 40 space 200A load center and now the Shed does too.

I had an early version of a "Total Energy Detective" (Google it) in my home so I could see the amount of power consumption I used for about 2 years before we built the shed...

Do I need 200 amps in either building? Not yet, but if I do, I don't have to do a thing.

Another thought.
With a single meter, I am billed at a residential rate. If I had a separate meter, I was told that would be commercial.

Chris

Glad I just stumbled on this thread because i was going to ask anyone in PA if they added power to a separate building and if so were they able to use a second meter or not? I thought I had heard about them wanting to charge a commercial rate but didn't ask someone who actually had that told to them.
Who is your powerco? PP&L by chance?
I am going to be getting new power installed in mine shortly but have yet to have powerco come out and run through my options.
I will be building a new house on the property and moving the power pole at that time so I'm hoping they let me put a main with meter on the corner of the pole building and then feed the existing set up from there. That way I can put a 200A service in the pole building and run the necessary 100A to the existing pole until we move forward with the house plans.
Do you have a double tap meter or a sub-panel set up?

 

[Pwrgeek]

Adding a second meter is going to cost you. Most likely the power company is going to make you pay the full cost because that meter won't see much load over time. Then there is the monthly service charge. Here's what I did.

My current house panel is a 200A
I added my shop and put in a 200A panel with 3" conduit back to my house panel.
Currently I have a 100A feeder in that conduit fed from a breaker in the house panel.
If I ever start tripping (which I don't think I will) that or add significant load to the shop then I will take the time to get a disconnect from the power company and move the feed from the shop to be tapped along with the feed to the house on the bottom side of my meter. Note that this is legal and allows by the power company here but is not everywhere. Both panels are service entrance rated so I'm good on that and what I would essentially have is two services on one meter.


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[theoldwizard1]

Adding a separate meter to an "out building" depends first on the POCO and second on your "situation". Most POCOs will charge a monthly fee for the meter and the second bill. My friend got a break on the rate because he has "livestock" (3 horse) although most of the barn is for equipment storage and hay.

 

[APEowner]

If you put you location in your profile then some members may have some local specific input. GJ is an international community and electrical advice from our Australian members may not be helpful for someone in Canada.

 

[sberry]

You don't have to strike an arc while the comp is running. Small welders really don't add much to the load, the modern 200 class mig is almost nothing as is a hoist. Even in my shop most tools are ran 1 at a time. Shop loads are very similar to kitchen with electric water heater.
I have put a lot of stuff on a 100A service during a season of changeover. 2 welding machines, 50A plasma, 5 hp air comp, 3 well, 5 hp pressure washer and about 20 people living in 3 units, with fridges and noraml electric appliances, coffee makers microwaves, some skillets etc. laundry, old lights with people had no interest in cost savings. Had 6 men working at the time.
When I hooked it up the insp said,,, bet you trip, never did. I had it fairly well balanced, wasn't air sanding and welding and pressure wash was frequent but normally wasn't welding at 50A when that happen but my well needs 20A service.

 

[sberry]

It would have been a poster place for a demand study. There was enough people and connected equipment to get a feel for some averaging.
I have also wired a couple dozen garages. A couple were active, 1 a bud ran auto repair out of for a career with a number 2 alum connected to his house thru a 60 and a 5 hp comp used daily, 1 helper. On occasion 20A of air cond and some greedy lights. Never a trip.

 

[sberry]

I have seen overloaded 60A service but not on a garage.

 

[sberry]

In most cases unless there is highly specialized continuous load a garage isn't even much a demand factor. A lot of the applied loads are offset by the fact you are not doing something else.

 

[sberry]

We have a lot more air comps in the world but the duty cycle is low and many are at 22A vs near 30. The real 3 hp 2 stage used to be more common. It was a nice niche unit, ran at 18 and didn't dim the lights while giving adequate service for most chore jobs.
This is a problem with the tankless water heater, got to make provisions for it or use gas but even though there are a crapload more welders today so many are at 20A than 40, right below a common water heater or cloths dryer and way more intermittent.
Its a little like more low flow shower heads, reducing the demand over the same time frame and a pipe will serve more people.

 

[exranger06]

We have a lot more air comps in the world but the duty cycle is low and many are at 22A vs near 30. The real 3 hp 2 stage used to be more common. It was a nice niche unit, ran at 18 and didn't dim the lights while giving adequate service for most chore jobs.
This is a problem with the tankless water heater, got to make provisions for it or use gas but even though there are a crapload more welders today so many are at 20A than 40, right below a common water heater or cloths dryer and way more intermittent.
Its a little like more low flow shower heads, reducing the demand over the same time frame and a pipe will serve more people.

You do realize you can go back and edit your posts, right? There's no need to make 5 different replies in a row.

 

[bczygan]

You do realize you can go back and edit your posts, right? There's no need to make 5 different replies in a row.

He does.

But that's how he talks.

Stream of consciousness.

Bill

 

[bczygan]

It's also why he has 16,200 posts and you have 144 (And I have 10,384!).

Bill

 

[myredracer]

Without doing a proper load cal. as per code, you are flying blind. Should be done from scratch including everything in the existing house. Should be the first question for the electrician. If it were me, I'd be talking to more than one electrician.

If upgrading from 100 to 200 amps, your utility company may want to upgrade the incoming drop and meter base regardless?

Not sure how the NEC treats home shops. Percentage of the feeder/overcurrent size to the shop or based on a basic per sq. ft. load plus equip. and electric heating (if so equipped)? If a one-man hobby shop, what is going to be the highest load? Take breaker size for largest motor (compressor?) and add FLA of largest equip. that *might* be running at same time (plasma cutter, stick welder, etc.) and add lighting, heating/AC, etc.? For a 5 HP compressor and plasma cutter, that can be 60 amp min. right there and then considering everything else, a 100 amp panel is likely the choice. You can have lots of outlets for various equip., but diversity comes into play

Perhaps you can buy an old analogue type utility company meter as there's gotta be a lot of surplus ones around now! You can't charge for power based on KWH, but you can apportion a monthly bill based on KWH readings of 2 meters, however the trick is to read your meter the same day as the power co.

FWIW, "my" attached shop has a 100 amp panel that also has a 60 amp sub-feed to an in-law suite above. Have a 5 HP compressor, plasma cutter, MIG welder and other stuff plus lighting (no electric heat) and has never been a problem. Basically, my shop has a 40 amp service, but diversity comes into play as the suite will never be running to the max. This was all squeezed to the limit per code. House has a 200 amp service and my shop and suite were part of original load calc. (CEC).

 

[Pwrgeek]

Home shops are kind of a red headed step child in the NEC. They are not commercial so don't require and engineered load calculation, but are also not "Occupiable space" so no base kVA load or load calculation methodology is provided. The best way to go is to estimate the appliance loads and then add lighting and some basic outlet load in.

 

[Autorotica]

Glad I just stumbled on this thread because i was going to ask anyone in PA if they added power to a separate building and if so were they able to use a second meter or not?

I thought I had heard about them wanting to charge a commercial rate but didn't ask someone who actually had that told to them.

Who is your powerco? PP&L by chance?

Do you have a double tap meter or a sub-panel set up?

Yes, PPL is my power company.

I used a 320A (RMS sometimes called 400A peak) meter base with dual load lugs. You are required to have a disconnect within X number of feet of the meter on both loads. The panel disconnect on the house panel is within acceptable distance to acts as the disconnect for the house. There is a separate disconnect on the side of the house for the "Shed" power before it goes gopher.

There were several reasons why I wanted to keep all my power on 1 meter. First, PPL only pays for the first transformer and wiring. More is on you.
2nd is the more attractive residential vs low usage commercial rate charges, not to mention all the taxes. Why pay them twice?
3rd, In the event of a significant power outage, I COULD feed the house from a generator in my shed all illegal and like. Yes, I will pull the meter.
Lastly, if some day down the road I decided to go solar to generate electricity, panels mounted on my "shed" roof will make KW credits for my house too (since they share a meter). I have more "shed" roof than I do house...

Watch who you talk to at PPL. First lady engineer we talked to told us we couldnt do anything we did. I had an electrician from my work help me with mine. He knew she didnt know what she was talking about and offered to send her some more information on what we were wanted to do so she could look it over.

Hope this helps!
Chris

 

[Nhrafan26]

Yes, PPL is my power company.

I used a 320A (RMS sometimes called 400A peak) meter base with dual load lugs. You are required to have a disconnect within X number of feet of the meter on both loads. The panel disconnect on the house panel is within acceptable distance to acts as the disconnect for the house. There is a separate disconnect on the side of the house for the "Shed" power before it goes gopher.

There were several reasons why I wanted to keep all my power on 1 meter. First, PPL only pays for the first transformer and wiring. More is on you.
2nd is the more attractive residential vs low usage commercial rate charges, not to mention all the taxes. Why pay them twice?
3rd, In the event of a significant power outage, I COULD feed the house from a generator in my shed all illegal and like. Yes, I will pull the meter.

Watch who you talk to at PPL. First lady engineer we talked to told us we couldnt do anything we did. I had an electrician from my work help me with mine. He knew she didnt know what she was talking about and offered to send her some more information on what we were wanted to do so she could look it over.

Hope this helps!
Chris

Thanks Chris! That does help.
Couple more questions.
Did you install the meter box, disconnects and everything after that yourself and just have them come and hook up power? I'm seriously considering this is what I will do if so.
I assume they supply the meter and the lock device on it but can you supply and preconnect your own meter base and just tell them you now want 200-400A service connected to it?

I was afraid of talking to a ******* there as I've already have numerous dealings with less than intelligent people there.

 

[myredracer]

I assume they supply the meter and the lock device on it but can you supply and preconnect your own meter base and just tell them you now want 200-400A service connected to it?

If you want a single 400 amp service (not multi-unit building), an ordinary meter base is only good up to 200 amps. After that, you need CT (current transformer) metering which entails a separate cabinet for the CT and conductors and then a standard meter base running off the output of the CT. Adds a lot of cost and if you don't absolutely need it is better to avoid it.

I did it in a previous acreage we owned. Had 400 amps in the 2K square foot workshop (was closet to the street) and then ran 200 amps to the house underground. Did it all myself (am an EE). It raised a red flag with our power co. as it is very unusual to have 400 amps in a residential property, esp. in a secluded and heavily treed rural area. They came out and inspected and tested everything to see if something illegal was going on and found nothing... It was overkill and added a LOT of cost up front and would not do again.

 

[Nhrafan26]

If you want a single 400 amp service (not multi-unit building), an ordinary meter base is only good up to 200 amps. After that, you need CT (current transformer) metering which entails a separate cabinet for the CT and conductors and then a standard meter base running off the output of the CT. Adds a lot of cost and if you don't absolutely need it is better to avoid it.

I did it in a previous acreage we owned. Had 400 amps in the 2K square foot workshop (was closet to the street) and then ran 200 amps to the house underground. Did it all myself (am an EE). It raised a red flag with our power co. as it is very unusual to have 400 amps in a residential property, esp. in a secluded and heavily treed rural area. They came out and inspected and tested everything to see if something illegal was going on and found nothing... It was overkill and added a LOT of cost up front and would not do again.

Ok, so same question eliminating the reference to 400A...
I always tend to think big and overbuild, something taught to me by someone a long time ago. I guarantee with what i'm doing in the garage 100A at a time will more than suffice. Also the size of the house will be fine with 200A service. No kids, just the GF and I so even if she's doing some heavy cooking, laundry at the same time, every light in the house on and me in the garage running the air compressor with the plasma, stereo blasting, A/C running, exhaust fan and lights on... I doubt we'll kill 200A.

 

[wyliesdiesels]

If you want a single 400 amp service (not multi-unit building), an ordinary meter base is only good up to 200 amps. After that, you need CT (current transformer) metering which entails a separate cabinet for the CT and conductors and then a standard meter base running off the output of the CT. Adds a lot of cost and if you don't absolutely need it is better to avoid it.

I did it in a previous acreage we owned. Had 400 amps in the 2K square foot workshop (was closet to the street) and then ran 200 amps to the house underground. Did it all myself (am an EE). It raised a red flag with our power co. as it is very unusual to have 400 amps in a residential property, esp. in a secluded and heavily treed rural area. They came out and inspected and tested everything to see if something illegal was going on and found nothing... It was overkill and added a LOT of cost up front and would not do again.

Not true.

Maybe your PoCo does CTs on a 400a(320a continous) but most others dont.

There is 400a pass through meters.

 

[Autorotica]

Thanks Chris! That does help.
Couple more questions.
Did you install the meter box, disconnects and everything after that yourself and just have them come and hook up power? I'm seriously considering this is what I will do if so.
I assume they supply the meter and the lock device on it but can you supply and preconnect your own meter base and just tell them you now want 200-400A service connected to it?

I was afraid of talking to a ******* there as I've already have numerous dealings with less than intelligent people there.

We changed the 200A meter base on the house to the 320/400 in a few hours. Pesky thing about living in the house when you are doing this work to it. You need it back on quick.

Before PPL showed up to disconnect power, we had the trench dug, conduit in, wire strung. Everything was inspected and backfilled all but the last 6' at the house. The 200A panel was hung in the shed and feeder wire hooked to the main breaker in the shed.

The linemen showed up at 8am and killed the power to the house. We had to cut the siding, mount the new meter base, re-feed the house. Mount the shed disconnect, Run wire and PVC to the shed disconnect and run the trench wire and PVC into the disconnect.

We had an appointment with the electrical inspection at 1pm. He wanted a separate bonding wire from all the new work connected to the original bonding wire. No problem, I will run and get the connector you are recommending to do that right now...

Around 3:30 the linemen showed back up and hung a new digital meter and lock that the POCO provides... and had a beautiful 000000 set of numbers on the display once they flipped the juice back on.

It was a very good day
Chris

P.s. Check out the linky's on the left side of this page... https://www.pplelectric.com/at-your-service/for-contractors-and-builders.aspx

 

[Pwrgeek]

Not true.



Maybe your PoCo does CTs on a 400a(320a continous) but most others dont.



There is 400a pass through meters.

We do pass through meters up to 600A here. 400A is the largest single phase service we offer though.


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[wyliesdiesels]

600a? Never seen a 600a class feed through.

 

[Pwrgeek]

They exist in three phase. Generally at 277/480 for a 100kVA service such as a large restaurant or medium sized commercial.


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[wyliesdiesels]

They exist in three phase. Generally at 277/480 for a 100kVA service such as a large restaurant or medium sized commercial.


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Never done bigger than a 400a 480Y/277v feed through. Past that its CTS.

480v feed through meters are dangerous. Seen quite a few blow up at pumping stations. I prefer CTS for 480v services but those arent typically done for small and medium pumping stations.

 

[Pwrgeek]

Never done bigger than a 400a 480Y/277v feed through. Past that its CTS.

480v feed through meters are dangerous. Seen quite a few blow up at pumping stations. I prefer CTS for 480v services but those arent typically done for small and medium pumping stations.

Yeah if it were me installing it I'd go with an IT meter install at those levels, but they cost more. As the rep on the utility side I don't care because our guys don't do live meter pulls on three phase meters anymore.

 

[CJ7VFR]

....A suggestion is if you have space in your current 100A house panel is to add a double pole 60A breaker. Run 2-2-2-4 aluminum MHF with a combination of 2-2-2-4 SER if you can't get conduit to the panels. Put in a 100A main breaker panel in the shop. Try it with the 60A feed and see how it goes. If you find you have no issues with power shortage or tripping back at the house then you're good to go....

This is exactly what I have in my garage from the house main panel! 60A double pole breaker that feeds the 100A sub-panel in the garage. Sub-panel has about 10 breakers in it for lights, garage door openers, outlets and a few spares.

I have 150 Amp service in my home, and the above setup has been plenty for the items I run in the garage, such as my MIG welder, grinders, lights, and all the other stuff.

This was installed in my house before I bought it, and there was even a hot tub the previous owners had hooked up to the garage sub-panel. The double pole breaker for the hot tub is still in the sub-panel as well as the run of heavy gauge wire coming off of it and going to back of the garage if I ever want to install a 240V outlet for a bigger welder or whatever.

Jim