Replacing Main Panel

I am starting renovations of my shop, which is an outbuilding with power from its own meter, to include a new roof, heat pump, insulation and additional wiring. I currently have 100 AMP service with a Cutler Hammer CH Main Panel. I was going to install a sub panel but Lowe's has a 200 AMP Cutler Hammer CH Main service panel on sale for only a little more than a 60 AMP panel.

My thinking is that I have the power company turn off the power and I replace the current 100 AMP main panel with the new 200 AMP panel. I take the main breaker from the old panel and put it in the new one (it is compatible) which will derate it back to 100 AMPS. I then have the utility company turn the power back on.

If I ever run out of power I simply upgrade service to 200 AMPS and have an electrician run the new power to the main breaker which I change to 200 AMPS. Any problems with this?

Why change the main breaker? Just leave it in. Electric company will just come out and pull the meter head. They may let you reinstall the meter head if you talk nicely to the tech.

Sounds like a deal to me. But why not just put the 200 amp breaker in there now? Wiring from the pole to the meter won't change. You would have to look and see if the wiring from the meter to the box would be sufficient or not. If not, even with a 100 amp main in it, it may have to be rated for 200 since that is what the box is set up for. Not likely you will need more than 100 amps in a one man shop, even with a big cyclone, TS and modest A/C-Heat you should be ok. But it's not going to hurt anything to have it set up for 200. That way, if you needed it, you wouldn't have the down time to change over. May not have any extra expense if the wiring from the meter to the box doesn't have to change. When I did the electrical on my detached shop with it's own meter, I just set up for 200 amp. I'll never use that, even with the planned (sometime in the distant future) PTAC unit installed. I needed the extra circuits, not the power it was capable of. Jim.

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Originally Posted by Tom Rossman

I am starting renovations of my shop, which is an outbuilding with power from its own meter, to include a new roof, heat pump, insulation and additional wiring. I currently have 100 AMP service with a Cutler Hammer CH Main Panel. I was going to install a sub panel but Lowe's has a 200 AMP Cutler Hammer CH Main service panel on sale for only a little more than a 60 AMP panel.

My thinking is that I have the power company turn off the power and I replace the current 100 AMP main panel with the new 200 AMP panel. I take the main breaker from the old panel and put it in the new one (it is compatible) which will derate it back to 100 AMPS. I then have the utility company turn the power back on.

If I ever run out of power I simply upgrade service to 200 AMPS and have an electrician run the new power to the main breaker which I change to 200 AMPS. Any problems with this?

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Check with your local codes. When I replaced my main panel I also had to add an exterior cutoff (fire reasons) which IIRC the power company supplied. HOWEVER, they required a licensed electrician to perform the install.

You are correct that you'll need to keep the 100A breaker until the exterior line is upgraded.

What is the service entrance wire size, 1/0 or 2/0? If it's 2/0 then you are good to go with the 200 amp panel. If it's 1/0, then stick with the 100 amp breaker.

Do you think you will exceed 100 amps in your shop? It may just be cheaper in the long run to add the sub panel.

I'll have to check the wire size from the meter. I may never need more than 100 AMPS, but this is a farm and there are times when a welder would come in handy. My reason for keeping the 100 AMPS for now is that I have no immediate need and I can wire the panel myself, but if I upgrade the service I will incur the cost of an electrician.

Upgrade to 200 amps now when you replace the panel. Do it once and get it over with. You will likely either have to have have a licensed electrician do this part or you will have to take a test to prove that you understand the electrical code before you will be allowed to do it yourself. If you just go with 100 amp now you will need to do it all over again when you decide to go with 200 amps. Welders require anywhere from 20 to 100 amps at 240 volts depending on what you buy. For farm use you will likely need one that draws 50-100 amps. You won't likely be using power tools with one hand and welding with the other, but having 200 amps available is just a really good idea long term.

Charley

Most utilities around here require that a new panel be inspected before they will energize it. That will likely mean getting a permit and a licensed electrician to sign off on the installation. If this is a major remodel, I'd probably go with the 200 A service, even if the service entrance conductors need to replaced. But on the other hand, a 100 A service can handle quite a bit of woodworking equipment.

When we upgraded our electrical service from 100 amps to 200 amps, our meter had to be replaced. That meant a new meter pan. Most folks use aluminum for the service feeder conductors from the meter to the main panelboard. You'd need 4/0 for 200 amps. It will most likely need to be inspected. In my jurisdiction, I could do all the work myself if I wanted to because it's my house - I would not be required to hire an electrician. One thing you may run into is the need to drive ground rods if you don't have 2 now.

I ditto every that Rob said. Everything he did I had to do back in April during my upgrade. Electric company disconnected, I replaced the meter pan and wire to the panel and the panel itself. Code enforcement inspection and sign-off was required before the electric company would come back and upgrade the weatherhead-to-meter wire and connect back to the grid. I feel lucky as the electric company did not charge me for any of their time or materials (including the meter pan).

Ditto on the ground rods.

FWIW, the wire from the pole to the weather is generally the same for 100 and 200 amps, but from the weatherhead to the meter pan is different (4/0 Al SEU vs 2 Al SEU).

In my county their are no permits required for any work on agricultural buildings on farms. If it was my residence a permit and inspection would be required. I haven't yet determined what my electric company will require. Thanks to all of you for your input. Lots of good experience again here at the Creek.

When we built in 2002, the Electrician installed Square-D QO series. It was the only brand he would use.

For the house we have 400 Amp service consisting of 2 200 amp main panels. The two panels are fed from a single buss which in turn is fed from a 'pole pig' across the driveway.

For the shop there is a separate meter that feeds a 200 amp main, and another 100 amp sub-panel. Both panels are nearly full.

Tom, Before you buy something on sale, check out a quality panel, Square-D. ( skip their Homeline series. QO is much better) As I recall, Home Depot handles Square-D.

Buy quality and spend your money once.

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Originally Posted by Rob Russell

One thing you may run into is the need to drive ground rods if you don't have 2 now.

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Be sure to check your local codes, as in my jurisdiction (Alaska), multiple independant ground rods are not permitted.

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Originally Posted by Jim Neeley

Be sure to check your local codes, as in my jurisdiction (Alaska), multiple independant ground rods are not permitted.

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Be sure to check the NEC, 2 ground rods 6 feet apart are now required for each service tie panel. I have seen local codes go above and beyond, but not under the NEC. But I'm not saying one doesn't.

Lowe's also carries Square-D (I love them and swapped one for another). Also check out superbreakers.net, they were about 15-25% cheaper than the borg for the same stuff (QO140M200 panel with cover; Lowe's $212, HD $199, Superbreakers $170) They have (as of today) free shipping on orders over $100.